Definitions and Pronunciation of Medical Terminology

Author: Disabled World
Published: 2009/01/11 - Updated: 2023/07/15
Publication Type: Glossaries / Definitions / Acronyms - Peer-Reviewed: N/A
Contents: Summary - Main - Related Publications

Synopsis: A to Z list of definitions relating to primary medical, disability, and health condition terms includes English pronunciation of various medical conditions and medications. Medical Terminology often uses words created using prefixes and suffixes in Latin and Ancient Greek. Greek prefixes go with Greek suffixes, and Latin Prefixes with Latin Suffixes. Prefix: Added in front of the term to modify the word root by giving additional information about the location of an organ, the number of parts, or the time involved.

Main Digest

This document provides an alphabetical glossary of definitions of medical terms including pronunciation of various diseases and health conditions. Medical terminology is a language used to accurately describe the human body and associated components, conditions, processes, and procedures in a science-based manner.

A medical dictionary is a lexicon for medical words. In medical dictionaries, definitions should, to the greatest extent possible, be:

Basic Medical Terminology List

Medical Terminology

Medical Terminology often uses words created using prefixes and suffixes in Latin and Ancient Greek. Greek prefixes go with Greek suffixes, and Latin Prefixes with Latin Suffixes.

Prefix: Added in front of the term to modify the word root by giving additional information about the location of an organ, the number of parts, or the time involved. Examples of medical terminology prefixes include:

  • Brachi/o - Arm
  • Cardi/o - Heart
  • Cyt/o - Cell
  • Derm/a, derm/o, dermat/o - Skin
  • Encephal/o - Brain
  • Gastr/o - Stomach
  • Hemat/o - Blood
  • Hist/o, histi/o - Tissue
  • Intestin/o - Intestine
  • Lapar/o - Abdomen, loin or flank
  • My/o - Muscle
  • Neur/o - Nerve
  • Ocul/o - Eye
  • Ophthalm/o - Eyes
  • Or/o - Mouth
  • Ot/o - Ear
  • Pulmon/o - Lungs

Suffix: Attached to the end of a word root to add meaning, such as condition, disease process, or procedure. Examples of medical terminology suffixes include:

  • A breaking down is -lysis
  • Blood terms end in -emia
  • Breathing terms end with -pnea
  • Inflammation is -itis
  • Pain terms end with -algia
  • Relating to disease is -opathy

Alphabetical Glossary and Definitions of Medical Terms

A B C D E F G HI L M N O PQ R S T U V W

A

4-Amino-Pyridine (4-AP)
An experimental drug that eases symptoms for some with MS, particularly if you are more Heat Sensitive. 4-AP is a Potassium Channel Blocker that improves the Conduction of Nerve Impulses through Axons with or without Demyelination. Its use may cause Seizure, Convulsion, or Dizziness.
Abatement
A reduction in the severity of symptoms.
Abiotic
Not related to living organisms.
Abortive
Cutting short the course of a disease.
Abrasion
Friction wearing away of the top layer of skin.
Abruption
A sudden breaking away or breaking off.
Accessory
Extra or supplementary to the main element.
Acetylcholine
An excitatory Neuro-Transmitter that is produced and used by Cholinergic Neurons to communicate with each other.
ACTH
Abbreviation for Adrenocorticotrophic Hormone, a Steroid produced by the Anterior Pituitary Gland, it stimulates the Adrenal Cortex to release several Hormones including Cortisol.
Acne
The commonly used name for pores clogged by sebum (also known as whiteheads and blackheads), pimples, nodules or cysts that can appear on the face, neck, shoulders, chest, back, upper arms and upper legs.
Acuity, Visual - Clarity of vision
Visual acuity is expressed as a fraction of normal vision. 20/400 means an Eye that sees at 20 feet what an average Eye sees at 400 feet.
Addiction
(say: uh-dik-shun) - This is a condition where you become dependent on, or can't do without physical substances or an activity to the point that stopping it is very hard and causes severe physical and mental reactions. Substances you can become addicted to include tobacco, alcohol, and drugs (both illegal and prescription drugs). Activities that can be addicting include lying, stealing, and gambling. Addiction can be treated with counseling and, in some cases, medication.
Adolescence
(say: add-ul-ess-ence) - The period of life from puberty to adulthood when a young person "grows up."
Adrenal glands
(say: a-dree-nal) - A pair of small glands, each of which sits on of the kidneys. These glands produce hormones that help control the body's heart rate, blood pressure, food use, and other functions. They make the hormone adrenaline, which the body releases in response to stress.
AIDS
(say: ayds) - This disease hurts the immune system (the body's way of protecting itself) so that it becomes easy to get dangerous infections and cancers. It is caused by the HIV infection.
Albinism
(say: al-byn-is-em) - A group of conditions that cause a problem with your body's ability to make melanin, which is the pigment (color) of your skin, hair, and eyes. This can make the skin and hair look very white.
Allergies
(say: al-ur-jee) - When someone has an allergic reaction to something, the body's immune system (which protects the body from outside substances), gives off a much bigger response than it normally would. The result is to have a reaction, such as sneezing or trouble breathing, to things that are usually not harmful, such as certain foods or animals.
Ambulatory
Ability to walk.
Amenorrhea
(say: uh-men-or-ee-uh) - When a woman does not have periods, either ever (after age 16), or they are a result of pregnancy, too much exercise, extreme obesity or not enough body fat, or emotional distress.
Amines
Are derived from the Amino Acid Tyrosine and are secreted from the Thyroid and the Adrenal Medulla.
Amino Acids
Chemical substances (building blocks of Protein) the body obtains from food. Essential Amino Acids (Only obtained from food) Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan and Valine - Non-Essential Amino Acids - (Body Can derive them) - Alanine, Argine, Asparagine, Aspartic Acid, Cysteine, Glutamic Acid, Glutamine, Glycine, Proline, Serine, Taurine and Tyrosine.
Analgesia
Loss of pain where the pain would normally be evident without loss of consciousness.
Anesthesia
Loss of feeling (Pain and Touch Perception) over part or all of the body.
Analgesics
(say: ah-nuhl-jee-zicks) - Analgesics are meant to relieve pain. These pain relievers don't get rid of what causes your pain; rather, they block the nerve pathways that send pain signals from the body part to the brain so that you don't hurt as much.
Anemia
(say: uh-nee-mee-uh) - When there are fewer red blood cells in the blood, it can cause health problems. This is measured by a decrease in hemoglobin, which provides the red color and moves oxygen through the body. There are many different types of anemia.
Anorexia nervosa
(say: an-or-eck-see-uh nur-vo-suh) - An eating disorder causes people to refuse to stay at a healthy body weight by not eating. People with anorexia have a fear of gaining weight and a picture of what their body looks like in their mind that is not what it is.
Anoxia
A condition or state that exists, when there is not enough Oxygen for tissue Oxygenation.
Antibiotic
(say: an-ty-by-ah-tiks) - Antibiotics fight bacterial infections by killing bacteria or stopping it from growing. Antibiotics can help your body's immune system fight off infections. Your doctor probably gave you an antibiotic if you have had strep throat.
Antibodies
(say: an-ty-bod-eez) - Proteins produced by white blood cells to fight bacteria, viruses, and other foreign substances.
Anterior Horn
Nerve Ganglia in the Gray Matter of the Spinal Cord containing Motor Neurons. The Posterior Horn (top) contains Sensory Neurons, which directly command Skeletal Muscles to perform quick or repetitive movements and are the final target of most Neural activity. Lesions in the Cerebrum, Basal Ganglia, Cerebellum, or Pyramidal Tracts affect their function. Example: Unstable gait or In-coordinate fingers. Anterior Horn Cell (Anterior Horn Neuron) - A Motor Neuron in the Anterior Horn Gray Matter. These cells innervate Muscle Fibers directly to move body parts.
Anti-Bodies
Are complex Glycoproteins (Immuno-Globulins) having a destructive impact on specific Antigens (i.e., Germs, Parasites, Bacteria, and other foreign substances) that stimulated their formation, conferring Immunity against exactly that Antigen. They are produced by Plasma Cells (B-Cells that have differentiated) in direct response to an Antigen's presence.
Antigen
A molecular protein or carbohydrate substance (Virus, Toxin, or Enzyme) which stimulates an "Immune Response." Any substance that triggers the Immune System to produce an antibody.
Antigen-Presenting Cell (APC)
A specialized type of Leukocyte, bearing cell surface Class II MHC (Major Histocompatibility Complex) molecules. APCs process and present Antigens to an Inducer, T-Cell, or Helper T-Cell. Examples: Macrophage, Neutrophil, Dendrite, and B-Cell
Anti-Inflammatory Drugs
Over-the-counter and prescription medications (Steroids) that are sometimes recommended to decrease inflammation. Aspirin and Ibuprofen are types of over-the-counter anti-inflammatory medications.
Aphasia
Loss of Speech expression or comprehension.
Apoptosis
Biologically programmed cell death - self-destruction (Cell Suicide).
Arteries
(say: ar-tuh-reez) - Thick-walled blood vessels that carry blood away from the heart to other parts of the body.
Asphyxiation
(say: as-fix-eeh-ay-shun) - Suffocation or smothering.
Aspiration
Inhaling food particles or fluids into the lungs. Asthma (say: az-muh) - When your airways are inflamed, causing you to gasp, feel shortness of breath, cough, and feel a tightness in your chest.
Asymmetry
Unequal or out of balance. Not the same on the two sides of the body.
Ataxia
The inability to maintain balance, while walking. The failure of muscular coordination, poorly coordinated gait, or limb movements. Ataxia is seen as a reeling, wide-based Gait. It is one of the most obvious signs of damage to the Cerebellum or its connecting Neural Pathways.
Attention Deficit Disorder
(say: A-D-H-D) - A behavioral condition that makes it hard for people to pay attention and concentrate.
Atrophy
A loss of substance refers to the loss of bulk in a Muscle, Nerve, or a shrunken Organ (Atrophied) from less than normal usage or from previous damage.
Atrophy, Optic
Pallor and loss of Blood Vessels on the Optic Nerve Head, as seen through the Ophthalmoscope. The loss of Myelin causes this or of Optic Nerve Fibers and Blood Vessels in the Optic Nerve.
Autism
(say: ah-tiz-em) - Disorder in the brain that affects both verbal and nonverbal communication (speaking and non-speaking) skills.
Autoimmune Disease
A process in which the body's Immune System causes illness by attacking elements, such as particular cells or materials, that are normal and essential for health. The Immune System is the body's defense against abnormal substances (such as Viruses or Bacteria) in the body. In autoimmune disorders, the Immune System attacks substances that are needed by (versus harmful to) the body.
Autonomic Nervous System
Regulates In-Voluntary (Unconscious) body functions, such as the activity of the Cardiac Muscle; Smooth Muscles (Example: Stomach and in the Skin); controls the secretions of internal Glands (Hormones); and the functions of the Respiratory, Circulatory, Digestive, and Urogenital Systems. Its two divisions counter-act each other to achieve the appropriate response: The Sympathetic Division accelerates the Heartbeat, constricts and dilatates Blood Vessels, dilates the Bronchi, and inhibits the Digestive System. It is most active under all conditions of Stress - it prepares the body for physical action (survival).
Axons
Are elongated Processes (Nerve Fibers) of Neurons. They enhance the speed of transmitting Nerve Impulses (Conduction) from one Neuron to another due to the combined benefits of their large diameters, Nodes Of Ranvier, and Myelin wraps.
Axonal damage
(Wallerian Degeneration), loss, or Atrophy are the cause of permanent MS Disability. Axons have been simplistically compared to electric wires; however, Axons are part of Neurons that actively generate electric current (Action Potential), while wires passively conduct current. (Also See MS Lesions & Axons and Disability)

B

B-Cell
A White Blood Cell (Lymphocyte) that makes Proteins known as Immuno-Globulins. A type of White Blood Cell that matures into Antibody producing cells (Plasma Cells) when exposed to specific stimuli (Antigen).
Babinski's Sign
When the sole of the foot is scratched, the big toe goes up instead of down. This indicates a Lesion (Plaque) somewhere between the Motor Cortex, on the Opposite side of the Brain, and the Lower Spinal Cord Neuron (Anterior Horn Neuron). This is a hallmark sign of Pyramidal Tract Disease (Spasticity).
Baclofen (Lioresal)
A prescription medication that relieves muscle Spasticity. Baclofen is an Antispasticity drug that interferes with the Spinal Cord activity, producing Increased Muscle Tone (Spasticity) in the Body's Smooth Muscles (For example Legs, Arms and Bladder). Baclofen is chemically related to the Neurotransmitter Gamma-Aminobutyric Acid (GABA), and it decreases the electrical activity of some Spinal Nerves by blocking GABA's receptor sites. It inhibits Reflex Spinal Nerve Centers that initiate muscle contractions, and its long-term use leads to increased muscle weakness.
Basal Ganglia
Are a group of Functionally Related Nuclei located bilaterally in the interior of the inferior aspect of the Cerebrum, the Mid-Brain, and the Diencephalon. They are the Largest Nuclei of the Brain and play an important role in Planning and Coordinating Motor Movements and Posture. Exert their influence over the networks that link the Motor Cortex to other Cortical Areas. The Basal Ganglia behave as a variable filter ensuring smooth Muscle Movements.
Benign
An abnormal growth that is not life-threatening.
Blood-Brain Barrier
A semi-permeable cell layer of Endothelial Cells (interior walls) within Capillaries of the Central Nervous System (CNS). The Blood-Brain Barrier prevents large molecules, Immune Cells, potentially damaging substances and foreign organisms (e.g., Viruses) from passing out of the bloodstream and into the CNS (Brain and Spinal Cord). A dysfunction in the Blood-Brain Barrier may underlie the disease process in MS.
Blood pressure
(say: blud presh-er) - As blood is pumped from your heart through your body, the blood exerts force or pressure against the blood vessel walls. Your blood pressure reading is a measure of this pressure. When that reading goes above a certain point, it is called high blood pressure or hypertension, which can be lowered and controlled with medication and changes in lifestyle and diet.
Bone marrow
(say: bone mair-oh) - Soft tissue found inside bones from which blood cells are produced and released into the bloodstream.
Brainstem
That portion of the Brain that connects the two Cerebral Hemispheres with the Spinal Cord. It has three major divisions: Midbrain, Pons, and Medulla Oblongata. This is the oldest part of the Brain, where most involuntary functions are controlled from. The area of Nerve Cells and Nerve Fibers at the base of the Brain is still within the Skull that connects to the Spinal Cord. The Medulla Oblongata, Pons, and Midbrain constitute the Brainstem. It connects the Spinal Cord's Axons to the remainder of the Brain and is responsible for many essential functions. All but two of the 12 Cranial Nerves enter or exit the Brain through the brain stem.
Brainstem Auditory Evoked Response (BAER)
A painless, diagnostic test in which electrical impulses from the base of the Brain are recorded in response to repeated clicks during Electroencephalography.
Bulimia nervosa
(say: buh-lee-mee-uh nur-vo-suh) - An illness defined by uncontrollable overeating, usually followed by making oneself throw up or purge (get rid of food) in other ways.

C

Cancer
(say: kan-ser) - When cells that are not normal develop and multiply. There are at least 200 kinds of cancers, which can grow in almost any body organ.
Capillaries
(say: kap-il-air-eez) - Tiny blood vessels that branch through body tissues to deliver oxygen and nutrients and carry away waste products.
Carbon dioxide
(say: kar-bun dy-ocks-ide) - A body waste product that is a colorless gas.
CAT (or CT) Scan
A diagnostic, computerized imaging system that uses X rays to determine the density of different spots in the body. A CT scan discloses normal and abnormal structures by producing a picture of the densities at thousands of spots in the Brain. However, all MR techniques provide superior imaging resolutions.
Cavity
Hollow space in the body containing one organ or more.
CD4+
A specific, Genetically determined type of T-Cell, that is thought to play a primary role in MS & EAE. It is also known as a " Helper T-Cell"; because it activates all Acquired Immune Responses only if it recognizes the presented MHC Class II complex.
Celiac disease
(say: see-lee-ack diz-eez) - When the small intestine is hurt from eating gluten and other substances like it (gluten intolerance). Glutens are found in wheat, rye, oats, barley, and other grains.
Cell
The body is made up almost entirely of many different kinds of Cells. Each Cell has a discrete inner core called the Nucleus, surrounded by Cytoplasm, and is encased in a Membrane separating it from other Cells.
Cell Membrane
The thin layer made of Proteins, Fats, and Carbohydrates, which form the capsule of a Cell, and is its outside "Skin."
Cellular Immunology
Also called Adaptive or Acquired Immunity, it is one part of the body's Immune System. Its chief component is the Cytotoxic T-Cell, which recognizes and destroys any Cell infected with a Virus or a Bacteria. It can directly kill Tumor Cells.
Central Nervous System
The part of the Nervous System covered by the Meninges. It includes the Brain, Spinal Cord, and Optic Nerves. The Nervous System comprises the Brain and Nerves: Afferent Nerves (from the Latin: ad = towards; ferro = I carry), which carry Sensory impulses from all parts of the Body to the Brain. Efferent Nerves (ex = from; ferro = I carry) through which "Messages" are conducted from the Brain to the Muscles and all of the Organs of the Body - The Somatic part of the Nervous System has Sensory components which convey Sensations from the Eyes, the Nose and other Sensory Organs to the Brain, and Motor components transmitting impulses to the Skeletal Muscles in the Limbs and Trunk permitting Voluntary control of Movements.
Centrocecal Scotoma
A Blind Spot that interferes with Central Vision because part of what you should see does not register - due to Demyelination along the Optic Nerve.
Cerebellum
Part of the Brain, located above and behind the Brainstem, it regulates Balance and Coordination of Movements. It has no direct connection to any specific movement. Example: Posture Imbalance. The Cerebellum cannot learn; hence once damaged, it will continue to malfunction - Cerebellar disease is evidenced as Complex Motor Dysfunctions: Changes in Speed and Cadence of Speech (Scanning Speech); Willed Movements resemble Tremor; and Eye Movement abnormalities (Nystagmus, Oscillopsia).

Cerebellar Function Disorders: The severity of symptoms is directly proportional to the amount of tissue destroyed - NOT to the specific location of the damage.

Asthenia: A lack of muscular strength, either during Voluntary Muscle Contraction or in Holding Posture.

Ataxia: In-coordination of muscular activity involving Tremor, failure of progression, and failure accurately to perform rapid alternating movements, such as tapping a finger. A swaying, unsteady, and wide-based gait is often the most obvious sign.

Dysmetria: Is difficulty measuring. Dysmetria is the failure to stop a motion at the intended point, with overshoot occurring (Example: The finger-to-nose test). This Cerebellar miscalculation is either from output failures or faulty inputs.

Fatigability: Muscles on the same side, where Cerebellar damage has occurred, tire more easily and have slower than normal contraction and relaxation times, producing slowed movements.

Hypotonia: The muscles feel flabby and offer less resistance to passive displacement. This may be from a lack of response to Spinal Tract input.

Mild Cerebellar Dysfunction: The inability to judge the range of limb movements without watching them.

Severe Cerebellar Dysfunction: The inability to perform limb movements smoothly and efficiently, even while watching them.

Cerebral Palsy
Say: se-reeb-rul pahl-zee. When injuries to the brain cause damage to the nerves and loss of movement. The injuries happen while a baby is growing in the womb or near the time the baby is born.
Cerebrospinal Fluid (CSF)
The fluid surrounding the Brain and the Spinal Cord, containing Glucose (sugar), Proteins, and other substances that are also found in Blood. However, it does not normally contain Red or many White Cells. CSF is filtered from the blood supply and secreted by a vascular membrane (Choroid Plexus) within the Brain's Lateral, Third, and Fourth Ventricles.
Cerebrum
Forms the great bulk of the Brain and consists of two Hemispheres, which occupy the entire vault of the Cranium and are incompletely separated from each other by a deep median cleft, The Longitudinal Cerebral Fissure. Cervix (say: sur-vicks) - The narrow entryway between the vagina and the uterus. The cervix muscles are flexible to expand to let a baby pass through when they are being born.
Chemokines - See
Cytokines
Chemokinesis
Indicates general movement, of many different cell types.
Chemotaxis
Literally means directed locomotion. It refers to the trail of secreted Cytokines that lead various Leukocytes to a site of Inflammation.
Chemotherapy
(say: key-mo-ther-uh-pee) - Chemotherapy (pronounced: kee-mo-ther-uh-pee), which is often known as chemo, is a term used for medications to treat cancer. Cancer happens when cells in the body develop wrong and grow in an uncontrolled way. Since cancer cells tend to divide very fast, chemotherapy works by getting in the way of these cells dividing and trying to stop cancer from spreading. Sometimes chemo can cure the disease by helping to get rid of all the cancer cells in the body.
Chlamydia
(say: kluh-mid-ee-uh) - The most common sexually transmitted (passed) disease in the U.S. Many women do not have symptoms of chlamydia. Untreated chlamydia can lead to pelvic infection and infertility (inability to become pregnant). People who are sexually active and who have multiple sexual partners are at the highest risk of getting chlamydia. A doctor can test and treat people for chlamydia.
Chronic Fatigue Syndrome
(say: kron-ick fah-teeg) - A very severe and long-term feeling of weakness and being tired, even after getting rest.
Circulatory system
(say: sur-kue-la-tor-ee sis-tem) - The heart, the blood, and the system of blood vessels that moves blood through the body.
Circumduction
A pattern of moving the Legs in which the person swings the upper Leg widely at the Hip. It is usually caused by partial Paralysis or Spasticity of the Limb.
Cleft lip and palate
(say: kleft lip and pal-it) - Abnormal growth of the lip and or roof of the mouth that happens before a baby is born. This can affect the lip's appearance and cause problems feeding as an infant and learning to speak.
Clinical depression
(say: klin-i-kul dee-presh-un) - Clinical, or major, depression is an illness that involves the body, mood, and thoughts. It affects how a person functions, eats and sleeps, feels about herself, and thinks about things. Depression is not the same as a passing "down" mood. It is not a sign of personal weakness or a condition that can be willed or wished away. This condition can be treated with medication and counseling.
Clonus
Involuntary movement of rapidly alternating contraction and relaxation of a muscle. Ankle Clonus is the most common form of Clonus. Reflexive Spasms in the Calf Muscles cause the Foot and Leg to bounce up and down when the Knee is bent and the toes are on the floor. Clonus is a hallmark sign of Spasticity - (Also See: Neurological Examination).
Clotting
(say: klod-ing) - The process by which the body forms a plug to seal damaged blood vessels and s bleeding.
Cognition- High-level functions carried out by the human brain, including
Comprehension and use of Speech, Visual Perception and Construction, Calculation Ability, Attention (information processing), Memory, and Executive Functions such as Planning, Problem-Solving, and Self-Monitoring.
Complement
Nine Serum proteins activated in sequence by an Antigen, forming Antigen-Antibody-Compound. (Symbol 'C'). It is part of the Non-Specific Immune System that generally deals with Bacteria infections - Complement upregulates Macrophage Cells, aiding their ability to find and digest foreign cells. It also calls Neutrophil Cells to the scene, which can kill Bacteria by producing Peroxide. (Also See: Complement System Products
Compression
To apply pressure to stop bleeding or prevent further injury.
Computed Tomography - See
CAT scan.
Coordination
An organized working together of muscles and groups of muscles aimed at bringing about a purposeful movement, such as walking or standing.
Corpus Callosum
Is a thick band of more than 200 million Myelinated transverse Nerve fibers. The Corpus Callosum is the largest and most important Commissural Fiber interconnecting the two Cerebral Hemispheres. It lies at the bottom of the Longitudinal Cerebral Fissure and is a general site for MS lesions - Its underside forms the roof of the two Lateral Ventricles; the front terminates in the Frontal Lobe and is named the Forceps Anterior or (Minor). The rear portion (the Forceps Posterior or Major) connects to the Temporal and Occipital Lobes and the Hippocampus Bands - Peduncles of the Corpus Callosum.
Cortex
Is the outer layer of any organ. Cortex, Cerebral - The outer layer of Nerve Cells that covers the entire surface of the Cerebral Hemispheres. Thinking and other Complex Neuronal Activity occur in the Cerebral Cortex - A 2.5 to 4.0 mm. thick layer of Neurons containing Gray Matter.
Cortex, Association
The Cortex is immediately adjacent to and closely connected to The Primary Sensory Cortex. Association Cortex gives form and meaning to raw Sensory messages received at the Primary Sensory Cortex through widespread connections to many parts of both sides of the Brain.
Corticospinal Tract - See
Pyramidal Tract
Corticotrophin - See
ACTH
Cortisone
A Steroid Hormone recommended to some people with Multiple Sclerosis, to reduce acute inflammations in the CNS. Cortisone treatments carry significant risks and should NOT be used for long-term treatment.
Cystic Fibrosis
(say: sis-tick fy-broh-sis) - A disease that causes both breathing and digesting problems. Cystic fibrosis runs in the family.
Cytokines
are proteins (usually Glycoproteins) of relatively low molecular mass and often consisting of just a single chain. They are chemicals secreted by various Leukocytes to activate other cells, coordinate, and regulate all important biological processes: Cell Growth, Immunity, Cell Activation, Inflammation, Tissue Repair, Fibrosis, and Morphogenesis - Cytokine Mechanisms: Autocrine - affects only the producing cell Endocrine - travel through the bloodstream, acting on numerous distant cell. Paracrine - act locally on target cells adjacent to the producing cell - Some Cytokines (i.e., IL-8) are also Chemotactic for specific cell types and are now called Chemokines. Although Cytokines are considered a Family, this is a Functional rather than a Structural concept; these Proteins are not all chemically related. (Example: Interferons, Tumor Necrosis Factor, and Interleukins).

D

Dantrolene Sodium (Dantrium)
An Antispasticity medication.
Deep Tendon Reflexes
The involuntary muscle jerks that are normally produced when the tendon is tapped at certain spots on a limb with a hammer. In MS, the tone of these Reflexes is heightened by lack of Cortical inhibition (Spasticity).
Decompostion of Movement
inability to sequence properly fine, coordinated acts.
Decubitus
An Ulcer (Sore) of the Skin resulting from pressure and lack of movement, such as occurs when a person is mostly in a bed or a wheelchair. The Ulcers occur most frequently in areas where the bone lies directly under the skin, such as the Elbow, Hip, or Tailbone.
Dementia
A generally profound and progressive loss of intellectual function, sometimes associated with personality change, that results from loss of Brain substance, and is sufficient to interfere with a person's normal functional activities.
Demyelination
The destruction, loss, or removal of the Myelin Sheath, which normally insulates some Axons, by a disease process. Multiple Sclerosis is a Chronic CNS Disease that results in Demyelination (Lesion or Plaque) following damage to Axons, Myelin, Oligodendrocytes, or Neurons.
Dendrite
The thin, afferent Process of a Neuron that carries newly received Nerve Impulses towards the Cell Body.
Dendrite Cell
A Phagocyte, these Leukocytes are found in the Spleen and other Lymphoid Organs; they typically use threadlike tentacles to enmesh Antigen, which they present to T-Cells.
Diabetes
(say: dy-uh-bee-teez) - When there is too much sugar in your blood. It can be caused by not having enough of the chemical that monitors blood sugar, called insulin, or by having resistance in your body to insulin.
Diagnosis
The art or act of identifying a disease from its Signs and Symptoms. The MS diagnosis requires clinical evidence (a positive, objective finding) on Neurological Examination of two or more CNS White Matter lesions in a person between 10 - 60 years old that occurred at two separate and distinct periods and of whom no other medical explanation exists ("Poser Criteria").
Diencephalon
The part of the Brain between the Brainstem and the Cerebrum. Its main components are the Thalamus, Subthalamus, Hypothalamus, and Epithalamus.
Diplopia
Double Vision, or the simultaneous awareness of two images of the same object that results from the failure of the two Eyes to work in a coordinated fashion. Covering one Eye will eliminate Double Vision by erasing one of the images. (Also See: Fasciculus, Medial Longitudinal Disability - A disability (resulting from an Impairment) is a restriction or lack of ability to perform an activity in the manner or within the range considered normal for a human being. Permanent MS disability results from Axons that have been severed and Atrophied; the temporary dysfunction experienced during an exacerbation is short-term, resolving after the Inflammation clears. (See: Normal-Appearing White Matter & Axons & Disability)
Disseminated
Scattered or distributed (Multiple).
Dizziness
A feeling of internal uneasiness, confusion, or light-headiness (passing out). Dizzy is commonly confused with Vertigo (a sensation your surroundings are spinning). While the feeling that you are spinning, not your surroundings, is Dizziness caused by Demyelination within the Cerebellum or its Nerve Pathways.
Douching
(say: doo-shing) - Douching is rinsing or cleaning out the vagina, usually with a prepackaged mix of fluids. The water or solutions are held in a bottle and squirted into the vagina through the tubing and a nozzle. Healthcare providers do not suggest douching to clean the vagina. Douching changes the delicate chemical balance in the vagina, which can make a woman more prone to bacterial infections.
Down Syndrome
(say: down sin-drohm) - When an extra copy of a chromosome is present when a baby develops. (A chromosome holds a cell's genetic information for a person.) The extra chromosome usually causes mental and physical abnormalities.
Drug dependence
(say: drug dee-pend-ins) - An addiction to drugs, or the inability to stop using harmful substances despite the harmful problems they cause.
Dysarthria
Slurring, inappropriate phrasing, and lack of modulation in Speech volume. Slurred and Scanning Speech are prevalent types of Moto dysarthria. They are generally a result of Lesions (Demyelination) in the Brainstem or within its connecting Nerve pathways - Poorly articulated Speech resulting from Neural dysfunction of the Muscles controlling Speech. The content and meaning of the spoken words remain normal.
Dysdiadochokinesia
Inability to perform rapid alternating movements, such as the nose-to-finger Neurological Test.
Dysesthesia
Distorted or Unpleasant Sensations experienced by a person when the Skin is touched. It is often referred to as an unpleasant ''Burning'' Sensation.
Dyskinesia
Are stereotypical, involuntary movements that affect muscle groups in varying combinations. Myoclonus and Dystonia are the most common forms of Dyskinesia seen in MS.
Dysmetria
Inability to control range of movements. Lesions cause a disturbance of coordination in the Cerebellum. A tendency to over or underestimate the extent of motion needed to place an arm or leg in a certain position.
Dysmenorrhea
(say: dis-men-or-ee-uh) - Painful menstrual periods that can also go along with nausea and vomiting, and either constipation or diarrhea. Dysmenorrhea is common among adolescents.
Dyspepsia
Indigestion, a feeling of being overstuffed.
Dysphagia
Difficulty in swallowing either solids, liquids, or both. It causes aspiration (food or saliva enters the airway), choking, and slow swallowing (possibly leading to inadequate nutrition). MS may cause Dysphagia if Lesions develop in the Brainstem or along its connecting Nerve pathways, disrupting the sequencing and control of motor programs that govern muscles regulating swallowing (Mouth, Pharynx, and Esophagus).
Dysphonia
Disorders of voice quality (including poor pitch control, hoarseness, breathless, and hypernasality) caused by spasticity, weakness, and in-coordination of muscles in the throat and mouth.
Dystonia
movement disorders where sustained muscle contractions cause twisting and repetitive movements or abnormal postures. The movements are involuntary and sometimes painful; they may affect a single muscle, a group of muscles such as those in the arms, legs, or neck, or the entire body - Dystonia results from an abnormality in the Basal Ganglia, where some of the messages that initiate muscle contractions are processed. Scientists suspect a defect in the body's ability to process these Neuro-Transmitters prevents Neurons from communicating with each other. Some of these include: GABA (Gamma-Aminobutyric Acid), which is inhibitory Dopamine is inhibitory Acetylcholine is excitatory - In movement, Acetylcholine released at Nerve endings causes muscle contraction. Norepinephrine and Serotonin are inhibitory Neuro-Transmitters that help to regulate Acetylcholine.

E

EAE (Experimental Allergic Encephalomyelitis)
A disease induced in lab animals that is similar to what is seen in humans with MS.
Edema
Swelling in the Brain or elsewhere caused by the abnormal accumulation of fluid.
Eating disorders
An eating disorder is a severe illness that requires help from a healthcare provider; the sooner, the better. Bulimia nervosa is an eating disorder where a person binges, eats a large amount of food all at once, then purges or forces themselves to vomit, and takes laxatives or diuretics (water pills). Starving yourself by eating very little or nothing at all is another eating disorder called anorexia nervosa. People who have this condition can have a strong fear of body fat and weight gain. Binge eating disorder happens when a person cannot control her desire to overeat and often keeps the extreme eating a secret. Unlike bulimia, with a binge eating disorder, a person does not purge her food. Extreme exercise to control weight is also a type of eating disorder.
Electroencephalography (EEC)
A painless diagnostic technique that records electrical activity in the Brain. (See: Evoked Potential Tests)
Emboli
Are small particles that Occlude (Block) the circulation of smaller Blood Vessels (Micro-Circulation).
Embolization
Is the process of Occlusion by Emboli.
Encephalitis
Inflammation of the Brain, sometimes called "sleeping sickness" caused by Viruses and other Microscopic organisms.
Endometriosis
(say: en-doh-mee-tree-oh-sis) - A condition where tissue that normally lines the uterus grows in other areas of the body. This can cause pain, irregular menstrual bleeding, and infertility for some women.
Endometrium
(say: en-doh-mee-tree-um) - The lining of the uterus.
Epilepsy
(say: ep-il-ep-see) - A brain disorder that causes seizures, which are uncontrollable body movements.
Epidemiology
The science concerned with the cause, frequency, and distribution of an infectious process or a physiological state in a human community.
Epitope
A single Antigenic Determinant that functionally is the portion of an Antigen which combines with an antibody. Epitopes are surface markers (Glycoproteins) present on all cells, consisting of different combinations of Amino Acids - Only this molecular configuration is recognized and bound by an antibody or T-Cell. Each Antigen normally displays more than one Epitope, and each one may attract a different Immune member. (See: Glycoproteins)
Erythrocytes
(say: er-ith-roh-syts) - Red-blood cells.
Estrogen
(say: es-tro-jin) - A female hormone produced by the ovaries. Estrogen plays important roles in puberty, the menstrual cycle, and in reproduction.
Etiology
The study of all factors that may be involved in the development of a disease, including the patient's susceptibility, the nature of the disease-causing agent, and how the person's body is invaded by the agent.
Evoked Potentials
Electrical signals recorded from the CNS in response to repetitive stimuli, such as a clicking noise (Hearing), flashing light (Vision), or a slight electrical shock (Sensory). Evoked Potentials utilize Electroencephalography to record how long the message takes to reach the Brain. - This test is useful in diagnosing MS because it can confirm the presence of a suspected lesion, which was not shown by an MRI scan, or identify the existence of an unsuspected lesion (Clinically Silent) that has not produced any symptoms.
Exacerbation
An increase in the severity of symptoms. Exacerbations of MS usually involve an increase in definite symptoms, lasting weeks or months. During the attack, numerous individual symptoms may come and go in succession. Acute attacks are usually followed by complete or partial remission (the reduction or diminution of symptoms) - A worsening or flare-up of Neurologic Signs and symptoms (such as Numbness, Weakness, or Lost Vision), usually associated with Inflammation and Demyelination in the Brain or Spinal Cord. The opposite of exacerbation is remittance - The appearance of new symptoms or the aggravation of old ones, lasting at least 24 hours. (Poser's Criteria)

F

Fallopian tubes
(say: fa-lo-pee-in) - The organs that connect the ovaries to the uterus. There is a fallopian tube on each side of the uterus. When one of the ovaries releases an egg, it travels through the fallopian tube toward the uterus. Fertilization (when a man's sperm and a woman's egg join together) usually happens in the fallopian tube.
Fasciculus, Medial Longitudinal (MLF)
A Nerve Tract in the Brainstem carrying instructions that coordinate horizontal Eye movements. The MLF coordinates the two Eyes when they look to the left or the right. A lesion in the MLF interrupts that coordination and the Eyes do not simultaneously turn in the same direction. Thereby producing two images in the Brain of the same scene - Diplopia (Double Vision).
Fatigue (Lassitude)
Is a debilitating kind of overall weariness, which is unpredictable and out of proportion to the activity. Any increase in body temperature will temporarily worsen fatigue; conversely, air-conditioning or a cool drink will lower your temperature, enabling you to feel better and continue.
Fecal Incontinence
Loss of control of bowel movements.
Flare-up - See
exacerbation.
Focal
A specific defined location or structure: of, relating to, being, or having a focus.
Focal Deficits
Impaired strength or Sensation over part of the body.
Footdrop
Impaired or Absent Voluntary Dorsiflexion of the foot - The normal Heel-Toe pattern of Walking (Gait) is disturbed, causing the toes to touch the ground before the Heel, resulting in tripping and loss of balance.
Frontal Lobes
The largest Lobes of the Cerebrum. The Anterior (Front) part of each Cerebral hemisphere is the control center for Learning, Behavior, Judgment, and Personality. The back part of the Frontal Lobe is the Motor Cortex which controls Voluntary Movements.

G

Gadolinium
A chemical compound that can be administered to a person undergoing an MRI procedure to enhance the distinction between new vs. old lesions. It also increases the scan's sensitivity, enabling imaging of lesions that would be missed on unenhanced T1 and T2 scans.
Gait Ataxia
Broad-based, staggering patterns of walking are usually a sign of Cerebellar damage, causing poor coordination of the Limbs.
Gamma Globulin (Immunoglobulin)
A protein fraction of Blood Serum that contains many different Antibodies. Increased percentages of Immunoglobulin and Ig Clonal Bands are characteristic of MSers' Cerebrospinal Fluid. Still, they are not conclusive proof you have MS
Ganglia
Are collections of Nerve Fibers and Neuron Cell Bodies. Neurons are large cells with appropriately large nuclei. Patches of Basophilic material and pigment are often seen in Ganglion Cell Cytoplasm.
Gene
The biological unit of Heredity. Genes determine the structure and function of all proteins in the body. In turn, these proteins govern body shape and function.
Genes
(say: jeans) - Genes come from both parents and are responsible for inherited characteristics, such as eye and hair color. Genes are in all body cells.
Genital region
(say: jen-i-tul) - The external reproductive or sex organs (sometimes referred to as a person's private parts).
Genetic Determinant
The unique Antigens that identify all Cells as Self, due to Heredity, i.e., HLA, to the Immune System.
Gingivitis
(say: jin-jih-vyt-is) - Inflammation of the gums, the first stage of gum disease. Gingivitis is caused by plaque deposits comprising bacteria, mucus, and food debris. Injury to the gums from harsh brushing or flossing can also cause inflammation.
Girdle Sensation (MS Hug)
A sensation of feeling a tight band (like wearing an overly tight girdle or corset) around your trunk that is experienced by some MSers, who have a lesion (old or new) on the Spinal Cord. Suppose it prevents you from taking in a full breath. In that case, it is best to treat with a course of IV Methylprednisolone -This Hug is usually the first indication of a new exacerbation when the inflammation is primarily centered around the Spinal Cord. Alternately, MS Hug can also be brought on by an increase in temperature (body core or ambient); if you have a pre-existing Spinal lesion. (Also See: Transverse Myelitis)
Glands
(say: glanz) - A collection of Cells specialized to secrete materials unrelated to their everyday needs. For instance, the Salivary Gland is a collection of Cells that secrete Saliva. Those Cells have no use for the product, which aids digestion in the Mouth and Stomach.
Glia Cells
outnumber Neurons by about five to one in the Nervous System; they have processes but do not form or conduct Action Potentials and retain the capacity to divide throughout life.
Gliosis (Glial)
Scars that are produced by enlargement of Astrocyte processes. When a portion of the CNS is damaged (Neuron or Axon), the Astrocyte processes enlarge and replace the damaged tissue. This process is called Gliosis, while the resulting permanent scar tissue is called Plaque (Sclerosis).
Glucocorticoid Hormones (Steroids)
Hormones that the Adrenal Glands produce in response to stimulation by Adrenocorticotropic Hormone (ACTH) from the Pituitary Gland. These Steroids (Prednisone, Prednisolone, Methylprednisolone, Betamethasone, Dexamethasone), which can also be manufactured synthetically, are artificially increased to serve both an Immuno-Suppressive and an Anti-Inflammation role in the treatment of acute MS exacerbations.
Granulocytes
(say: gran-you-lo-syts) - A subset of Leukocytes (Polymorphonuclear Leukocytes) that are part of the Adaptive Immune System and includes Neutrophils, Eosinophils, and Basophils.
Gray Matter
Portions of the CNS where Nerve Cell Bodies are concentrated. The cortex is Gray Matter. So are the Anterior and Posterior Horns of the Spinal Cord and more.

H

Halitosis
(say: hal-i-toe-sis) - Offensive or bad breath.
Heat Sensitivity
Causes a transient worsening of symptoms and may make vision blurry (Uhthoff's Syndrome). Bodily functions return to normal when the body cools off. The Neuron can resume transmitting Nerve Impulses - Without its Myelin coating, all CNS tissue is more sensitive to heat and prone to stop transmitting electrical signals (Conduction Block) when the body's core temperature is increased by just 0.5 degrees C.
Hematemesis
Blood in vomit.
Hemianopsia
One-sided Visual Field loss.
Hemiparesis
Sensory loss or weakness of the face, Arm, and Leg on one side of the body.
Hemiplegia
Paralysis of one side of the body, including one Arm and one Leg.
Hemoglobin
(say: heem-oh-glo-bin) - Substance containing iron found in red blood cells, which helps the blood carry and deliver oxygen to body tissues.
Hemophilia
(say: heem-o-feel-ee-ah) - A disease that makes it difficult for the blood to clot, which is how the blood sticks together to s flowing. Without clots, a simple cut can cause someone to lose a dangerous amount of blood. This disease affects mostly boys.
Hepatitis
(say: hep-uh-tyt-is) - Inflammation of the liver, caused by infections from bacteria, viruses, or toxins such as alcohol or drugs. There are different types of hepatitis, including Hepatitis A, B, C, and autoimmune hepatitis.
Herbal supplements
(say: er-bul sup-le-ments) - Herbal supplements are different types of medicines that come in a variety forms, such as teas, vitamin pills, or creams. There has not been a lot of research done on herbal supplements to know how well they work or how safe they are, so you must ask your doctor before taking anything that they have not given you.
Histamine
A chemical present in cells (Mast Cells) throughout the body. Its release opens Endothelial Cell junctions in the Venules' Blood-Brain Barrier and upregulates Adhesion Molecules. It is one of the substances responsible for Inflammation, stimulates the production of Stomach Acid, and narrows the Bronchi in the Lungs.
Histocompatibility Genes
Are a category of DNA Genes called Class II Major Histocompatibility complex Genes. They create the HLA Antigens by which the Immune System recognizes the self.
HIV
(say: H-I-V) - HIV stands for the human immunodeficiency virus, which destroys the immune system that protects the body. This makes it hard to fight infections. People with HIV may not have symptoms for up to 10 years but can give it to others through unprotected sex and sharing drug needles. HIV leads to full-blown AIDS.
Hodgkin's lymphoma
(say: hodj-kinz limf-oh-muh) - A type of cancer that affects the tissue found in lymph nodes (glands that protect the fluids in your body), the spleen, the liver, and bone marrow.
Homicide
(say: HOM-uh-side) - The killing of one person by another. Homicide is not legal and is a punishable crime.
Hormone
(say: HOR-moan) - A substance secreted in the body and carried through the Blood-Stream to organs and tissues, where it serves a regulatory function (Hormones travel in the blood and can act, far from the site of secretion). (Also See: Glucocorticoid Hormones & Pituitary Hormones)
Human Leukocyte Antigen (HLA)
The Self-Made-Antigen (Major Histocompatibility Gene) displayed on the surface of all cells that identifies them to the Immune System, as belonging to self. These Antigens must be presented with Antigenic Peptides for T-Cells to begin an Immune Response.
HPV
(say: H-P-V) - A sexually transmitted disease that can cause wart-like growths on the genitals. There are many types of HPV, but some do not cause growth. Regular pap tests or HPV tests can catch the virus. HPV can lead to pre-cancerous cell changes in the cervix, so detection and treatment are important.
Human T-Cell Lymphotropic Virus type 1 (HTLV-1)
A Retrovirus currently being studied that operates in human T-Cells and causes a disease called Tropical Spastic Paraparesis.
Hypoxia
Indicates a severe Oxygen shortage in tissue.

I

Iatrogenic
A condition that appears as a result of treatment of another condition.
Idiopathic
Of unknown cause.
Immune System
(say: im-yoon) - The Immune System is a collection of Cells and Proteins that works to protect the body from potentially harmful infectious Microorganisms (microscopic life-forms), such as Bacteria, Viruses, and Fungi - It is a defense mechanism characterized by recognition of Non-self, Specificity, and Memory. It has two basic components: Innate Immunity and Acquired
Immunity
The Immune System plays a role in the control of Cancer and other diseases but also is the culprit in the phenomena of Allergies, Hypersensitivity, the rejection of Transplanted Organs, Autoimmune Diseases, and Medical Implants. Having protection or resistance to a particular disease or poison, i.e., Gamma Globulin.
Immunoglobulin
A group of Glycoproteins (Antibodies), present in Serum and tissue fluids that recognize and bind to Antigens. They are produced by Plasma Cells and are integral in Adaptive Immune Responses. There are five classes of Immuno-Globulins (Ig): IgG, IgA, IgM, IgD, and IgE.
Immunizations
(say: im-you-niz-a-shuns) -Immunizations keep people from getting sick by immunizing, or protecting, the body against certain infectious diseases. Vaccines contain parts or products of infectious organisms or whole germs that have been changed or killed. A vaccine prepares the body's immune system to fight off infection by that germ. Most immunizations that prevent you from catching diseases like measles, whooping cough, and chicken pox are given by a shot.
Immunosuppression
Any form of treatment or drug which slows or inhibits the body's usual Immune Responses. Some examples used to treat MS are Cyclosporine, Methotrexate, and Azathioprine. Impairment - Any loss or abnormality of Psychological, Physiological, or Anatomical structure or function. It is a deviation from the person's normal biomedical state. An impairment is thus any loss of function directly resulting from injury or disease.
Impotence
Poor or Absent erection of the Penis.
Incidence
The number of new cases of a disease in a specified population over a defined period.
Incontinence
The inability to hold urine or stool until urination or defecation is intended.
Inflammation
A tissue's Immunological response to injury, characterized by mobilization of White Blood Cells and Antibodies, Swelling, and Fluid Accumulation.
Infratentorial
Interior Cerebral areas (Diencephalon), along the Ventricles, just below the under-surface of the Temporal and Occipital Lobes. Most common Infratentorial MS lesion sites: The Floor of the Fourth Ventricle - The Cerebellar Peduncles - The Surface of the Pons
Insulin
One of many Hormones which helps the body, change the food we eat into energy; Insulin helps us store energy for later use. After we eat, it causes sugar (Glucose) to leave the blood and enter the body's cells - to make fat, sugar, and protein. Between meals, it aids in utilizing stored fat, sugar, and protein.
Interferon
An interfering Protein that neutralizes Viruses Cytotoxic T-Cells of the Immune System produce it in response to foreign Nucleic Acids (produced by Viruses and Bacteria), thereby protecting uninfected cells - Interferon-alpha () and Interferon-beta, form the Type 1 class of Interferons. At the same time, Interferon-gamma () is a Type 2 Interferon. These Proteins are Anti-Viral Cytokines and potent Immune Regulators and Growth Factors.
Interleukins (IL-1 to IL-18)
A well-characterized group of Cytokines, mainly produced by Leukocytes, which mostly act upon other Leukocytes. Their main action targets vary from T-Cells and B-Cells to Fibroblasts and Endothelium. They have a broad spectrum of functional activities that regulate the activities and capabilities of many cell types and regulate Inflammation and Immune Responses.
Intractable
Difficult to cure or alleviate.
Intrathecal
Occurring in the space under the Arachnoid membrane, which surrounds the Brain and Spinal Cord (generally within the Cerebrospinal Fluid).
Ischemia
Is an insufficient Blood Supply to an Organ or Tissue.

L

Lateral Spinothalamic Tract
A Sensory Nerve Tract in the Anterior-Lateral (Front-Side) portion of the Spinal Cord. Interruption of the LST results in loss of Pain and Temperature sensations below the level of the lesion on the Opposite Side of the body.
Lesion
Any damage to tissue structure or function. A Scar is a Lesion. So is Cancer, an MS Plaque, a Stomach Ulcer, or a Pimple. On T2 MRI scans, old lesions register as *Black Holes- Hyperintense (less tissue) areas. New inflammatory lesions are seen as *Bright Spots- Hyperintense (higher fluid content) areas. - MS lesions on conventional MRIs [T2] first appear as small, Ovid-shaped, focal bright spots having discrete borders. Cerebral lesions are located centrally, near the Midline, asymmetrically arrayed, deep within the White Matter, and always surround a blood vessel (Venule) that is near the Cerebrospinal Fluid (Ventricles, or Spinal Cord).
Leukocytes
(say: loo-ko-syts) - Any of the colorless blood cells, lack Hemoglobin, and contain a Nucleus (also called White Blood Corpuscle).
Lhermitte's Sign
An electrical sensation (Shock, Lightning Bolt) that some MSers experience when flexing the neck, tilting, or lowering the head towards the chest. It begins at the base of the skull and runs down the Spine and into the limbs before exiting through the hands or feet. (Also See: Tic-Douloureux)
Ligand
A Molecule or Ion that can bind another Molecule.
Lobe (Of The Brain)
A major division of the Cerebral Hemisphere. Each Cerebral Hemisphere is divided into the Frontal Lobe, Parietal Lobe, Occipital Lobe, Temporal Lobe, and Limbic Lobe.
Lupus
(say: loo-pus) - One of the diseases that cause the immune system, which normally protects the body, actually to attack it. Lupus can cause problems with the skin, joints, and organs inside the body.
Lymphocytes
(say: limf-oh-syts) - A variety of White Blood Cells (Leukocytes), which are part of the body's Cellular Immune System - White Blood Cells play a large role in the Immune System, by responding to Antigens and triggering reactions in other cells. They are produced by Bone Marrow Stem Cells, and depending on their site of subsequent maturation, they develop into either: B or T-Cells.
B-Cells
are responsible for Humoral Immune Responses; they produce Immuno-Globulins (Antibodies) to fight Extracellular infections (Bacteria, Fungus, etc.).
T-Cells
are responsible for Cell-Mediated Immune Responses (Cellular Immunology) including both effector and regulatory cells. Helper T-Cells prime both Antibody-mediated and Cell-mediated effectors for the attack, while Suppressors await the signal to change, slow, or end the assault.
Natural Killer Cells (NK)
recognize classes of cells and destroy tumor cells on contact without needing a co-stimulator signal.
Cytotoxic T-Cells (CD8+)
handle the destruction of host cells that have become infected by Viruses or other Intracellular Pathogens.
Helper T-Cells (CD4+)
heighten the production of antibodies by B-Cells and regulate the activities of all effector cells. A functional subclass of T-Cells that helps to generate CD8+ Cells and cooperate with B-Cells in the production of Antibody-mediated responses - CD4+ Cells only recognize Antigens that are presented in association with MHC Class II molecules.
Suppressor T-Cells
suppress B-Cell activity and seem to be in short supply during an MS attack (exacerbation). - A functionally defined population of T-Cells, which reduce the Immune Responses of other T-Cells or B-Cells, or switch the response onto a different pathway.

M

Macrophage
Develop from Monocytes, a Phagocyte Cell that helps initiate and is involved in all stages of Immune Responses. It recognizes and can digest (Phagocytize) all foreign Antigens (i.e., Bacteria, Viruses) and Cell Debris. Macrophages are also an integral part of Demyelination and participate in tissue repairs. In the CNS, they are called Microglia Cells and Kupffer Cells in the Liver, where they Phagocytize Bacteria, other Pathogens, and old red blood cells.
Macrophage-Activating Factor (MAF)
Actually, several Cytokines, including Interferon, released by activated T-Cells, which together induce activation of Macrophages, making them more efficient in Phagocytosis and Cytotoxicity.
Mast Cells
Develop from Basophil Cells (Polymorphonuclear Leukocytes), they reside in tissues, regulating Vascular Permeability (Blood-Brain Barrier) and Smooth Muscles. They possess IgE receptors, participating in immediate hypersensitivity reactions by de-granulation (Release) of Heparin, Serotonin, Histamine, and other Vasoactive Amines.
Medulla Oblongata
The lowest major segment of the Brainstem.
Memory
(See: Cognition)
Menarche
(say: men-r-kee) - The first menstrual period or beginning of menstruation.
Menopause
(say: MEN-o-pawz) - The last menstrual period or end of menstruation. The average age of menopause is 50. After menopause, a woman can no longer become pregnant.
Meningitis
(say: men-in-jyt-is) - A dangerous infection that affects the brain and spinal cord.
Menstruation
(say: men-stroo-ay-shun) - The monthly period or menstrual bleeding. During menstruation, the extra blood and tissue that build up inside the uterus during the menstrual cycle are expelled through the vagina, usually over 3-7 days.
Muscular Dystrophy
(say: mus-kew-lar dis-trof-ee) - A group of disorders that causes muscles to be weak and causes loss of muscle tissue.
Microemboli
Refers to any small Emboli that predominantly Occlude (Block) the Microcirculation.
Microglia
(See: Glia Cells - Microglia)
Monoclonal Antibodies
Are laboratory-produced antibodies, which can be programmed to react against a specific Antigen, to suppress the Immune Response.
Monocyte Cells
Develop from Stem Cells, are effective Antigen Presenting Cells, and patrol the bloodstream, searching for Antigens. In time, Monocytes migrate into tissue and develop into Macrophages.
MR or MRI
(See: Nuclear Magnetic Resonance).
Multiple Sclerosis
Is a Chronic Neurologic Disease of the Central Nervous System (CNS), occurring only in humans. MS is classified as both a Demyelinating and an Axonal Disease.(See: Multiple Sclerosis as a Neuronal Disease)- Although increasing evidence points to an Autoimmune aspect, no single Antigen or Immune System Dysfunction has been identified, so the cause of MS remains unknown. (See: Multiple Sclerosis - The range of MS disease patterns, stages, and symptoms, explaining today's standard diagnostic tests.)
Myelin
A fatty (Lipid) substance forming a multi-layered sheath around some Nerve Fibers (Axons) in the Central, Autonomic, and Peripheral Nervous Systems. Within the CNS, Myelin is formed by Oligodendrocytes and consists of their Cell Membranes (Cytoplasmic Extensions), which wrap themselves around Axons - This Myelin Sheath covers and insulates sections (Internodes) of CNS Axons, thereby reducing the electrical Capacitance between a Neuron's negatively charged Axonal Membrane (Internodal Axolemma) and the surrounding positively charged Extracellular Fluid - Myelin greatly increases the conducting velocity of an Action Potential; while expending much less energy than an Un-Myelinated Axon would require, to send an identical Action Potential, along the same distance.
Myelin Basic Protein
One of the components of Myelin, which may be increased in the Cerebrospinal Fluid of some - but not all MSers - following a Demyelinating episode.
Myelitis
An inflammatory disease of the Spinal Cord. In Transverse Myelitis, the inflammation spreads across the Spinal Cord, resulting in a loss of its normal function to transmit Nerve impulses up and down, as though the Spinal Cord had been severed.
MyxoVirus
A Virus that causes disease in Mucous Tissue such as the Throat, Mouth, or Lung. Example: (Influenza) See: Virus

N

Necrosis
Is tissue decomposition resulting from the loss of its Blood and Oxygen supply, Burns, or other severe injuries. It can also be caused by some medications commonly used to treat MS - skin necrosis occurs after a subcutaneous injection when the body is intolerant to the medication. Necrosis of the hip and shoulder joints is caused by the long-term use of steroids. (See: Steroids)
Nerve Fibers
(Axons) - Are long, sparsely branched Processes, having non-changing diameters that extend from a Neuron's Cell Body and connect another Neuron's Axon, Dendrite, or Cell Body and bodily organs that compose their Neural Network - A bundle of Nerve Fibers (Axons). The Fibers are either: Afferent - leading towards the higher Brain (CNS) and serving in the Perception of Sensory stimuli of the Skin, Joints, Muscles, and Inner Organs; Efferent - leading away from the higher Brain and Mediating contractions and relaxations of Muscles or Organs.
Nerve Impulse
The electrochemical charge (Action Potential) carried by an Axon.
Neurologic Disease
Any disorder of the Nervous System. There are many different neurologic diseases, among which is Multiple Sclerosis.
Neuron
An individual Nerve Cell and the key data-processing cell of the Nervous System. Each has a Nucleus within a Cell Body and one or more Processes (Extensions) called Dendrites and Axons. Neurotransmitters - These are chemicals (Small Molecules or Hormones) stored in small Synaptic Vesicles clustered at the tip of the Axon (terminal buttons) - When a Nerve Impulse arrives for transmission to the next Neuron, they cross the Synapse enabling message transmission to another Neuron or the Stimulation of an Effector Cell (Muscle or Gland) - When a Neurotransmitter is received, it either Excites (Depolarizes) or Inhibits (Hyperpolarizes) the Postsynaptic Neuron. More than 100 organic molecules are thought to act as Neurotransmitters - Some examples are Acetylcholine, Norepinephrine, GABA, Serotonin, and Dopamine, although each acts in different responses. Some are Excitory, such as Acetylcholine, Serotonin, Norepinephrine, and Dopamine. Some are associated with Relaxation, such as Dopamine and Serotonin.
Neutrophils
A Phagocyte member of Leukocyte Cells, they are the Adaptive Immune System's first line of defense against Bacterial infections. After leaving nearby Blood Vessels, these cells follow chemicals produced by Bacteria in a cut or scratch and proceed to locate and eliminate the invader.
Nodes Of Ranvier
Are the only gaps between Myelin sections (Internodes) along Myelinated Axons, where Sodium (Na+) and Potassium (K+) can be exchanged (Salatory Conduction); hence, continuing the Nerve signal's rapid transmission, to its target. They are crucial electrical refresher sites where Action Potentials are restored.
Nuclear Magnetic Resonance (MRI, MR, NMR)
A diagnostic test that uses the magnetic properties of different substances in a Magnetic Field to produce images of the Brain, Spinal Cord, and other soft tissues of the Body. An MRI shows areas of Sclerosis (Lesion, Plaque) when they are larger than 2mm (Macroscopic Lesions). Scans can NOT show Microscopic Lesions, as they are too small for current imaging resolutions, but are included in your Lesion Load and Atrophy totals.
Nocturia
Inability to hold urine while sleeping, resulting in bed-wetting and disrupted sleep, due to repeated bathroom trips. (See: Neurogenic Bladder, Urgency with Hesitancy)
Nystagmus
A back and-forth twitching Eye movement (Rhythmical jerking movements), with the fast component maximal, towards the side of the Cerebellar Lesion. Characterized by rapid, involuntary Eye movements in the horizontal or, occasionally, the vertical direction. (Also See: Oscillopsia; Optic Neuritis; Retrobulbar Neuritis)

O

Oligoclonal Bands (Gamma Globulin Bands)
A positive finding from the chemical analysis of Immunoglobulin (IgG) found in Cerebrospinal Fluid. IgG Banding indicates an Intrathecal production of Antibodies, commonly found during a current or very recent exacerbation, in 90% of MSers undergoing Diagnosis.
Oligodendrocyte
(See: Glia Cells - Oligodendrocyte)
Optic Atrophy
Degeneration of the Optic Nerve, due to Demyelination and loss of Blood Vessels on the Optic Nerve Head, seen as pallor through the Ophthalmoscope.
Optic Nerve
The bundle of Nerve Fibers formed by the light-sensitive Retina of the Eye that extends from the Eye and connects to the Brain.
Optic Neuritis
Inflammation of the Optic Nerve (behind the Eye), causing Blurred Vision, Transient or Permanent Loss of Vision and is often associated with Pain in or behind the Eye when Vision deteriorates. Episodes may come and go but usually peak in a few days and rec; everyone takes six weeks to six months - with or without any particular treatment. Optic Neuritis is very common in many, but not all MSers and usually occurs in only one Eye. It is one of the first diagnosable signs that you may have Multiple Sclerosis. Although Optic Neuritis is very upsetting and scary, it is considered a good indication of having a milder MS course when it is the presenting symptom - When the inflammation involves the first part of the Nerve and can be seen at the Optic Disk, usually during an Eye Examination, it is called Optic Papillitis. This may cause colors to appear washed out or faded, and bright lights generally make seeing difficult, even with good color contrasts. Wearing yellow-tinted sunglasses or adding a light photo-ray tint to your eyeglass prescription will greatly relieve the glare of bright lights.
Organelle (Little Organ)
Particles within Cells that are covered with their membrane. Many different kinds of Organelle occur within Cells, each with a special function.
Oscillopsia
Continuous, Involuntary, and Chaotic Eye movements that result in a Visual Disturbance in which objects appear to be Jumping or Bouncing. (Also See: Nystagmus)
Orthotic
A mechanical appliance such as a Leg brace or Shoe inserts that are specially designed to Control, Correct, or Compensate for impaired limb function. Ovulation (say: ov-yoo-lay-shun) - When the ovaries release an egg, about once each month, as part of the menstrual cycle.
Ovaries
(say: o-var-eez) - Two organs (about the size of an almond or grape), one on each side of the uterus, in the pelvis of a female. The ovaries contain eggs (ova) and make female hormones. When one of the ovaries releases an egg about once each month as part of the menstrual cycle, it is called ovulation.
Over-the-Counter
Over-the-counter medicines are medicines you can buy at a pharmacy or store without a prescription, or an order from your doctor. Examples include cold medicine, medicines for stomach pain, or pain relievers.

P

Paralysis
Inability to move a part of the body.
Paraparesis
A weakness but not total paralysis of the lower extremities (legs).
Paresis
Partial or incomplete paralysis of a part of the body.
Paresthesias
(Gr.- para = abnormal, aisthesis = sensation) Sensations of Burning, Prickling, Creeping on the Skin, or "Pins-and-Needles" that develop with damage to a Pain Pathway (Nerve or Axon). This may or may not be associated with any physical findings on Neurological Examination - Lesions or damage in the Dorsal Columns (Spinal Cord) often register as tingling and numbness due to irritation of Sensory Nerve fibers as they die. These sensations range from merely annoying to severe pain. Sometimes, even the light touch of clothing can be painful.
Paroxysmal Symptom
Any one of several symptoms which have a Sudden Onset, apparently in response to some movement or Sensory Stimulation, last for a few moments, and then subside. They are thought to be caused by the short-circuiting of electrical impulses along Demyelinated Axons.
Pelvic Inflammatory Disease (PID)
(say: P-I-D) - A general term for infection of the lining of the uterus, fallopian tubes, or the ovaries. Most cases of PID are caused by bacteria that cause STDs, such as chlamydia and gonorrhea. The most common symptoms include abnormal vaginal discharge (fluid), lower stomach pain, and sometimes fever.
Peptides
Short strings (groups) of Amino Acids, which Immune Cells (Leukocytes) use to identify Cells as belonging to Self or Antigen.
Nervous Peripheral System
All the Nerves and Nerve Cells outside the Central Nervous System.
Periventricular Region
The area surrounding the four fluid-filled cavities (Ventricles) within the Brain. MS plaques are commonly found within this region.
Phagocyte
A Polymorphonuclear Leukocyte that consumes cellular debris and invading microorganisms. Neutrophils, Dendrites, and Macrophages are Phagocytes or eating cells (phago = "eating," cyte = "cell") - These APCs present Antigens on their cell surfaces that are the chemical remains (Peptide) of the Organism. Antigens presented in this way activate specific responses and destroy the invading Organism.
Phagocytosis
The engulfment, digestion, and subsequent processing of debris or a Microorganism by Antigen Presenting Cells.
Phospholipids
Are fatty substances that are a major component of Myelin.
Pituitary Gland
(often called the master gland) is located in a small bony cavity at the base of the Brain; it has two Lobes: The Anterior and Posterior Lobes - The Anterior Pituitary is Glandular. A stalk links the Pituitary to the Hypothalamus, which controls the release of Pituitary Hormones. The Posterior Pituitary is used to store Hormones until they are needed. Also, See Glucocorticoid Hormones.
Placebo Effect
The beneficial result of a medication or other therapy that has no proven value or effect in the management of a medical problem. The apparent benefits occur because of an individual's expectation that the therapy will help. Some people respond to the placebo or sham treatment simply because they are convinced that they have been given the real treatment and may even have a real physical reaction to the placebo.
Plantar Reflex
A Reflex Response obtained by drawing a pointed object along the outer border of the sole from the Heel to the little Toe. The normal Flexor Response is a bunching and downward movement of the Toes. An upward movement of the big Toe is called an Extensor Response, or Babinski's Sign, which is a sensitive indicator of disease (Spasticity) in the Brain or Spinal Cord.
Plasma
(say: plaz-muh) - The liquid part of blood, which contains nutrients, proteins, minerals, and dissolved waste products.
Platelets
(say: playt-lats) - Small cells floating in the blood that play a key role in blood clotting.
Plaque
The Scarring of Neural tissue that develops after Demyelination and Lesions.
Polycystic Ovarian Syndrome
(say: P-C-O-S) - PCOS is a mild hormonal imbalance that can cause irregular periods, unwanted hair growth, weight gain, and acne. This is a common condition that begins during the teenage years.
Prednisone
A Steroid drug related chemically and therapeutically to the Steroid Hormones normally made in the Adrenal Glands. Prednisone and other Steroid medications carry significant Long-Term Risks.
Pons
The portion of the Brainstem, just Superior to the Medulla Oblongata, is about 2.5cm. in length. It contains the Respiratory Center, which controls the mechanism that permits the Outflow of air from the Lungs.
Posterior Column
Bundle of Axons in the Posterior part of the Spinal Cord. Interruption of this column on one side of the Spinal Cord causes loss of Position Sense below the level of the interruption on the Same Side of the body.
Prevalence
The number of all new and old cases of a disease in a defined population at a particular point in time.
Primary/Progressive MS
A clinical course of MS characterized from the beginning by progressive Disability, with no plateaus or remissions or an occasional plateau and very short-lived, minor improvements.
Proactol
Herbal Weight loss supplement made with Neopuntia. Proactol
Progressive/Relapsing MS
A rare type of MS that shows disease progression (increased Disability) from the onset but with clear, acute relapses, with or without full recovery after each relapse.
Prospective Memory
The ability to remember an event or commitment planned for the future. Thus, a person who agrees to meet or call someone at a given time on the following day must remember the appointment when the time comes. Both Prospective and Recent Memory are frequently major Cognitive problems for MSers.
Proteins
A group of complex organic compounds, composed of Amino Acids, with defined three-dimensional structures (encoded in DNA) that controls its particular function. Proteins are responsible for all reactions and activities of Cells.
Pseudo-Exacerbation
A temporary aggravation of disease symptoms resulting from an elevation in body temperature or another stressor (ex., an infection, fatigue, heat, or constipation), that disappears once the stressor is removed. A pseudo-exacerbation involves only pre-existing symptoms (flare-ups) rather than new disease activity or progression.
Puberty
(say: pyro-bur-tee) - The process of developing from a child to sexual maturity, when a person becomes capable of having children. In a girl, puberty includes a growth spurt, the development of breasts and hips, the growth of body hair, and the beginning of menstruation (having periods).
Pyramidal Tract (Corticospinal)
One of the major Motor Tracts from the Brain to the Spinal Cord. The Pyramidal System is specialized for making discrete movements; its Axons fibers form the Pyramids of the Medulla Oblongata. It originates in the Cortex of the Frontal Lobe. It communicates directly with Motor Neurons in the Spinal Cord to activate Fine Motor Control. Example: tying shoelaces, writing, etc. It orchestrates the Motor Response and helps to Specify Body Posture at all levels of the Spinal Cord. It Adjusts Muscle Tone to counter the changing centers of gravity Plaque here causes the symptoms of Spasticity: Muscle Tightness, Ankle Clonus, Flexor Spasms, Exhaustion, Loss Of Muscle Power, and Paralysis

Q

Quadriplegia
The paralysis of both arms and both legs - Quadriplegia and Paraplegia Difference

R

Recent Memory
The ability to remember events, conversations, the content of reading material, or television programs from a short time ago (i.e., an hour or two ago, or last night). MSers with MS-related memory impairment typically experience the greatest difficulty remembering these things from the recent past.
Red blood cells
(say: red blud sels) - Small, hemoglobin-filled blood cells that carry oxygen to the body's tissues.
Referred pain
Pain that is felt in another area to the source of this pain.
Reflex
An involuntary response of the Nervous System to a stimulus, such as the Stretch Reflex, which is elicited by tapping a Tendon with a reflex hammer; or Absent Reflexes can be indicative of Neurological damage, including MS, and are therefore tested during the standard Neurological Exam - An unconscious muscle tightening that is mediated by Anterior Horn Neurons, in the Spinal Cord. Increased muscle tone (tightness, spasticity) is normally an early finding in Multiple Sclerosis.
Reflux
Going in a backward direction.
Relapsing/Remitting MS
A clinical phase having distinct relapses (also called acute attacks or exacerbations), with either full recovery (no disability), or partial recovery and lasting disability. There is no visible disease progression (worsening) between attacks. Still, stable periods, span, mask, and the continuing sub-clinical disease process - Relapsing forms of MS are the most common beginning types, comprising 85% of the total. However, 50% of cases will progress within 10 - 15 years, and an additional 40% within 25 years of onset, as the disease evolves into the Secondary/Progressive phase.
Relaxation techniques
These are techniques, or things that you can do, to help you relax. They are often used for reducing stress. Relaxation techniques include meditation (sitting still, breathing slowly, and clearing your mind), yoga, deep breathing, and visualization (closing your eyes and seeing a scene that relaxes you, such as a beach or a mountain lake).
Remission
A decrease in the severity or number of MS symptoms and signs, or their temporary disappearance. The opposite of remission is exacerbation.
Remote Memory
The ability to remember people or events from the distant past. MSers tend to experience few if any, problems with their remote memory.
ReMyelination
The repair or replacement of damaged Myelin, which usually occurs spontaneously in the early course of MS, but is a prolonged process. Early MS damage (Lesion) is repaired (Remyelinated) by Oligodendrocytes extending new cytoplasmic extensions that spiral around (rewrap) Axons to form new Myelin sections (Internodes).
Reproductive organs
(say: ree-pro-duck-tiv) - The parts of the body involved in reproduction (producing a baby). In a female, they include the uterus, ovaries, fallopian tubes, and vagina.
Reticular Formation
A vital part of the Autonomic Nervous System, which is scattered like a cloud throughout most of the length of the Brainstem. These nuclei receive Nerves innervating the Face and play an important role in Arousing and Maintaining Consciousness. Visual or Acoustical Stimuli and Mental Activities can stimulate this system to maintain Attention and Alertness.
Retrobulbar Neuritis
Inflammation of the second part of the Optic Nerve (behind the Eye), which an Eye Examination cannot see. It is one of the most common beginning symptoms of Multiple Sclerosis. Still, it can also occur as an isolated Neurological Lesion incident, with full recovery of Vision and no further progression to Clinically Definite MS. (Also See: Optic Neuritis)
Retrovirus
A type of Virus named for its ability to convert RNA to DNA and thus use Genetic material to make the proteins it needs to survive and reproduce itself, causing several diseases in the process. Rheumatoid Arthritis (say: roo-much-toid arth-rytis) - A painful disease that causes joints, tissues, and sometimes other parts of your body to swell.
Romberg's Sign
Loss of Position Sense indicated by the inability to remain immobile (without swaying) while standing with Feet together and Eyes closed. (Also See: Babinski's Sign)
Romberg Test
An examination by a physician during which your positional sense of balance is tested. It entails you standing with feet together, arms outstretched in front, and eyes open and closed.

S

Scanning Speech
Un-natural Speech characterized by Staccato-like Articulation, that sounds clipped because the person unintentionally pauses between syllables and skips some of their sounds.
Sclerosis
Hardening of tissue. In MS, sclerosis is the body's replacement of lost Myelin around CNS Axons with scar tissue. Early Lesions are usually Remyelinated, and functions return. However, suppose Astrocytes make Sclerosis (Gliosis). In that case, Myelin can NOT be repaired, and the damage is permanent.
Scoliosis
(say: sko-lee-oh-sis) - When the spine curves either away from the middle of the body or to the side.
Scotoma
A Gap or Blind Spot in the Visual Field. (Also See: Centrocecal Scotoma)
Secondary/Progressive MS
A clinical course of MS which initially relapses/Remitting and then becomes progressive at a variable rate, possibly with an occasional relapse and minor remission - MS that begins with a pattern of clear-cut relapses and recovery but becomes steadily progressive over time with continued worsening between occasional acute attacks. (Also See: Types of MS)
Segment, Spinal Cord
One defined portion of the Spinal Cord, which is - Eight Cervical Segments (Neck & Upper Extremities); Twelve Thoracic Segments (Chest); Five Lumbar Segments (Lower Trunk & Lower Extremities); and Five Sacral Segments (Buttocks, Bowel, Bladder, and Sexual Function).
Self-esteem
How you feel about yourself - how you feel about who you are, the way you act, and how you look. When a person does not think too highly of themselves, she is said to have low self-esteem.
Sensory
Receptor mechanisms monitoring changes in both external and internal environment and convey this data to the CNS. Such as Pain, Smell, Taste, Temperature, Vision, Hearing, Touch, and Proprioception (Acceleration and Position In Space). This awareness enables the coordination and quick implementation of survival reactions.
Sensory Cortex
The network of Neurons located along the Cerebral Parietal Lobe's surface.
Sensory Input
Stimuli that the Nervous System receives from the external or internal environment: Includes Pressure, Taste, Odor, Sound, Light, and Blood ph.
Sensory Neurons
The Cell-Bodies of Axons carrying signals from receptors that transmit information about the environment, to processing centers in the Brain and Spinal Cord. Spinal Cord Neurons processing messages from peripheral receptors are sometimes called Afferent Neurons or inter-neurons.
Sensory Pathways (Afferent)
Axons carrying information from organs and tissues to Cortical control centers (Thalamus, Parietal Lobe).
Sequela
A condition following or caused by a previous disease; an after effect of illness.
Sign, Neurologic
An objective physical problem or abnormality identified by a doctor during the Neurological Examination. Neurological signs may differ significantly from the symptoms reported by the patient because they are identifiable only with specific tests and may cause no noticeable symptoms - Any evidence of malfunction perceived by a physician. (Also See: Babinski's Sign And Romberg's Sign)
Somatosensory Evoked Potentials
A painless test that records nerve message transmission times within the Brain in response to repeated electrical shocks applied to a Peripheral Nerve. Slower response times are typically present in early MS, especially the Nerves of the legs and feet - Normally, Brain's reaction to such stimuli is almost instantaneous. Demyelination or a Lesion in the Nerve Pathway causes a delay so that reception time will be significantly slower than normal. (Also See: Evoked Potentials)
Spasticity
CNS damage caused by Multiple Sclerosis prevents Nerve messages from reaching Brain's higher control area (Cerebellum); thus, it is unable to inhibit the reflex orders (Muscle Contracting) initiated in the Spinal Cord - Muscle groups normally work together, when one is flexed, its opposing muscle is relaxed. MS disrupts this communication causing muscles to stay tight or contract needlessly. This increased muscle tone is called Spasticity. Increased Muscle Tone - Tightness or Stiff Muscles, usually around a Joint - Increased resistance to movement. It refers to the stiffness in the Limb, usually in the Leg. Spasticity often accompanies Weakness, but it is possible to have Spasticity without Weakness and to have Weakness without Spasticity - Spasticity tends to occur most frequently in a specific group of muscles that are responsible for maintaining our upright posture, referred to as Anti-Gravity or Postural Muscles. These include the Calf (Gastrocnemius), Thigh (Quadriceps), Buttock (Gluteus Maximus), Groin (Adductor), and occasionally the Back (Erector Spinae) Muscles.
Spina Bifida
(say: spyna bif-id-uh). This congenital disability stops the bones of the spine from finishing forming right. It can cause the legs to be paralyzed (unable to move) and cause loss of control over the bladder.
Spinal Cord
is the communication link between the Brain and the Peripheral Nervous System (PNS) inferior to the head; it integrates incoming Nerve impulses and produces responses through Reflex mechanisms - The cord extends from the Foramen Magnum to the level of the 2nd Lumbar Vertebra. It comprises Cervical, Thoracic, Lumbar, and Sacral Segments, which are named according to the area of the Vertebra Column from which their Nerves enter and exit. Thirty-one pairs of Spinal Nerves exit the Spinal Cord and pass out of the vertebral column through the Intervertebral Foramina. Nerves to the extremities enter and leave through: The Cervical Enlargement - in the inferior Cervical region corresponds to the location at which Nerves that supply the upper limbs enter or exit the cord. The Lumbosacral Enlargement - in the inferior Thoracic and superior Lumbar regions is the site at which the Nerves that supply the lower limbs enter or exit - In cross-section, the Spinal Cord consists of a central Gray portion and a peripheral White portion. The White Matter consists of Nerve Tracts, and the Gray Matter consists of Nerve Cell Bodies and Dendrites. An Anterior median Fissure and a Posterior median Sulcus are deep clefts partially separating the two halves of the Cord. Splenium - the rear portion of the Corpus Callosum, above the Pineal Gland.
Steroids
(See: Glucocorticoid Hormones)
Stimulus
Elicits a physiological response.
Subcutaneous
Just beneath the skin
Suppressor T-Lymphocytes
White Blood Cells (Lymphocytes) which inhibit or stop certain Immune activity, and which may be in short supply during an MS exacerbation.
Symptom
Any report of malfunction perceived by a patient. Common symptoms of MS include Visual Problems, Fatigue, Sensory Changes, Weakness or Paralysis of Limbs, Tremors, Lack of Coordination, Poor Balance, Bladder or Bowel Changes, and Cognitive Changes.
Synapse
The specialized junction between Neurons; there is no anatomical continuity between them. Instead, the gap is crossed by, Neurotransmitters that diffuse across the Synapse, completing the connection from the end branch of a Presynaptic Axon to the Dendrite, Cell Body, or Axon of a Postsynaptic Neuron.
Syndrome
A set of symptoms that indicate towards a certain condition, disease or abnormality.

T

T-Cell
A type of white blood cell (Leukocyte), whose activities are influenced by their development in the Thymus Gland - Are responsible for Cell-Mediated Immune Responses - used to fight viral infections. (See: Lymphocytes) - A white blood cell (Lymphocyte) that dominates the Cellular Immune response to an Antigen.
Tandem Gait
A test of balance and coordination that involves alternately placing the Heel of one foot directly in front of the Toes of the other Foot.
Thalamus
Most Sensory Input initially projects to the Thalamus, where Afferent Neurons synapse with Thalamic Neurons, which send projections from the Thalamus to the Cerebral Cortex. The Thalamus also has other functions, such as influencing Mood and General Body Movements associated with Strong Emotions such as Fear or Rage.
Thrombocytes
(say: throm-boh-syts) - Platelets, which are in your blood.
Thymus
A small Gland in the Chest above the Heart. The Thymus influences the behavior of White Blood Cells and other elements of the body's Immune System.
Tic-Douloureux
See Trigeminal Neuralgia.
Titer
A level or strength of a substance such as Antibodies in Serum.
Tolerance
The T-cells inability or diminished sensitivity to an Antigen.
Toxic Shock Syndrome
(say: T-S-S) - A sporadic but dangerous illness that affects the whole body. TSS is caused by bacteria that make toxins (poisons) in the body. Tampon use can make it easier for bacteria to enter the body. Symptoms include high fever that comes on suddenly, dizziness, rash, and feelings of confusion.
Tract
A bundle of Axons traveling together. In most cases, the Origin and Destination of Axons in a Tract are quite similar.
Transverse Myelitis
Inflammation in the Spinal Cord interfering with Nerve function below the level of the inflammation. (Also See: MS Hug) - An acute attack of inflammatory Demyelination involving a Spinal Cord section. Paralysis and Numbness are experienced in the Legs and Trunk below the level of inflammation. (Also See: Spinal Cord Segment)
Tremor
Either with Intention or Sustention indicates Cerebellar damage (Muscle In-Coordination). Intentional Tremor becomes shakier, directly correlating to your increased concentration to reach, grasp, or do something.
Trigeminal Neuralgia (Tic-Douloureux)
Pain in the Face that comes on abruptly that sometimes develops with Multiple Sclerosis. Lightening-like, acute pain in the face caused by Demyelination of Nerve Fibers, where the Trigeminal Nerve's Sensory Root for that part of the Face enters the Brainstem - Tic (sudden jerk) Douloureux (caused by pain) most commonly strikes inside and outside of the cheek, back across the face towards the ear, and the upper teeth. The Anticonvulsants [Tegretol (Carbamazepine); Dilantin (Phenytoin); Neurontin (Gabapentin)] effectively relieve the pain of Trigeminal Neuralgia.
Tumor Necrosis Factor (TNF)
A Cytokine released by activated Macrophages, similar to Lymphotoxin that activated T-Cells secrete. It enhances the activation of T-Cells, and induces the proliferation of T-Cells and B-Cells - TNF also attracts additional Macrophages and Granulocytes to the site. This prompts Macrophage and other Immune Cells to release tissue-damaging, Oxygen-containing substances and Prostaglandins to promote Inflammation.

U

Uhthoff's Syndrome
A metabolic by-product of exercise, or an increase in body temperature causes a Reversible Conduction Block in a Demyelinated Optic Nerve, resulting in the temporary loss or blurriness of Vision - Uhthoff's Symptom (temporary Visual Loss with exercise), is an indication of Optic Neuritis and a major risk factor for the recurrence of Optic Neuritis and the further development of Multiple Sclerosis.
Urinary Retention
Involuntary accumulations of excessive Urine in the Bladder.
Urinary Tract Infection
(say: yoor-in-ar-ee trakt in-feck-shun or U-T-I) - An infection that happens in the bladder or tube leading to the bladder. A type of bacteria usually causes it.
Uterus
(say: yoo-ter-us) - Also called the womb. The uterus is a pear-shaped, hollow organ in a female's pelvis where a baby develops during pregnancy. The uterus comprises muscle with an inside lining called the endometrium. The endometrium builds up and thickens during the menstrual cycle to prepare for a possible pregnancy each month. But if no pregnancy occurs, the extra tissue and blood are shed during menstruation.
Uveitis
Inflammation within the middle layer of the Eye (the Uvea) between the Sclera and Retina, affecting any of the three parts of the Uvea: The Iris - the colored part of the Eye. The Ciliary Body - behind the Iris, which makes the fluid inside the Eye. The Choroid - a Vascular lining beneath the Retina.

V

Vagina
(say: vah-jye-na) - Sometimes called the birth canal. The vagina is a muscular passage that leads down from the cervix (the lower part of the uterus) to the outside of a female's body. During menstruation, menstrual blood flows from the uterus through the cervix and out of the body through the vagina.
Veins
(say: vayns) - Thin-walled blood vessels that receive blood from capillaries and return it to the heart.
Ventricles
The four cavities in the CNS that contain the Vascular membrane (Choroid Plexus), which secrete Cerebrospinal Fluid. There are two Lateral Ventricles (one in each Hemisphere); they connect with the Third Ventricle in the Diencephalon - In the Midbrain, the Cerebral Aqueduct connects with the Fourth Ventricle (located between the Pons, Cerebellum, and Medulla Oblongata). Which joins the Central Canal of the Spinal Cord and the Subarachnoid space which surrounds the Central Nervous System. (Also See: Ventricular System)
Vertigo
A feeling of internal uneasiness, confusion, or light-headiness (passing out). The term Dizzy is commonly confused with Vertigo (a sensation your surroundings are spinning) - While the feeling that you are off-balance, vaguely out-of-sorts, and spinning (not your surroundings) is Dizziness. Demyelination within the Cerebellum or its Nerve Pathways may cause Dizziness. (Also See: Vertigo/Dizziness)
Virus
A living agent, the smallest and simplest form of life, which depends on other living cells to reproduce itself. The first known Virus was discovered in 1898.
Visual Evoked Potentials
A diagnostic technique for recording electrical response times in the CNS to repeated visual stimuli. This is a very sensitive way of detecting Optic Neuritis - Evoked Potential Tests can confirm the presence of a suspected Lesion and identify an unsuspected Lesion (Clinically Silent) that has produced no symptoms. They are instrumental in diagnosing MS, and VEPs are abnormal in approximately 90% of MS cases.
Vitamins
(say: vy-tuh-mins) - Vitamins and minerals are drugs that replace or fix low levels of important natural substances in your body. You get vitamins and minerals from food. Some types of food have more of these good substances than others. If you need extra vitamins and minerals, you may have to take pills that have them.
Vulva
(say: vul-vuh) - The vulva covers the entrance to the vagina and has five parts: Mons pubis, labia, clitoris, urinary tract opening, and vaginal opening.

W

Wallerian Degeneration
Is Axonal Degeneration without local Inflammation and before local Demyelination that results from a distal injury to the same Axon. Wallerian Degeneration commonly occurs sometime after a distant Axonal part has been severed.
White blood cells
(say: white blud sels) - Blood cells that are involved in fighting infection and helping to heal wounds.
White Matter
The common term for Myelin and the Medullary Body and consists of: Myelinated Axons and supporting cells (Astrocytes). The Medullary Body is the Cerebrum's deep interior (includes the Corpus Callosum, surrounds the Basal Ganglia, and parts of the Ventricles) - Various other Nerve Pathways (i.e., Cerebral Peduncles, Corticospinal Tract, and Medial Fasciculus Longitudinal) interconnect the entire Brain to the Spinal Cord). White Matter constitutes a larger percentage of the Central Nervous System (CNS) than Neurons (Gray Matter) and Demyelination, damage to Neurons, their Axons, or Myelin cause MS Symptoms.

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