Biology of Disease

Cofactor proteins Those that bind tozymogensand their

protease products and increase the specificity and

speed of the activation of the zymogen.

Colitis Aninflammationof the colon.

Compensation In acid–base disorders, the physiologi-

cal mechanisms that attempt to return the pH of the

blood to values within the reference range.

Conjugate vaccines These are those formed when a rela-

tively poorly immunogenic material is attached to a

protein that is much more immunogenic.

Contact allergies Reactions produced by a number of

chemicals that directly affect the skin leading to a

delayed typehypersensitivity.

Control samples Samples that are identical in composi-

tion to test samples except that they contain known

concentrations of the testanalyte.

Corneal arcus Opaque fatty deposits around the

periphery of the cornea that occur in familial

hypercholesterolemia.

Cretinism A congenital condition in which a child suffers

from mental retardation, muscle weakness, short stat-

ure, neurological signs and is often dumb and mute

because of the failure of the thyroid gland to develop

normally during embryonic growth.

Cytogenetics The microscopic study of chromosomes.

Cytokines A general name given to a large family of pro-

teins which resemble hormones in being secreted

by cells and stimulating activities in other cells after

binding to receptors on their surfaces.

Cytotoxic cells White blood cells that directly destroy

infected cellsin cell-mediated immunity.

Cytotoxic T lymphocytes They develop from TCcells,

which have been stimulated by animmunogen.

Debridement The surgical removal of infected or necrotic

tissue.

Degenerative diseases Diseases involving the progressive

loss of body tissues and impairment of their functions:

usually associated with aging.

Dehydration This occurs when water loss from the body

exceeds intake (compare withoverhydrated).

Diarrhea The frequent passage of feces that are larger in

volume and more fluid than normal. It is not a dis-

ease but a symptom of an underlying condition that

increases intestinal movements, accelerating the pas-

sage of the contents through the gastrointestinal tract

leaving insufficient time for fluid reabsorption.

Diastole Relaxation of the heart’s ventricles.

Dietary reference values Guidance values as to the

amounts of nutrients that should be ingested, rather

than exact recommendations.

Diploid The presence of pairs of chromosomes in a cell.

Normal human somatic (body) cells contain 23 pairs

of chromosomes (compare withhaploid).

Dissection (with respect to arteries) The separation of the

layers of the wall of an artery.

Dominant Genetically controlled factors that are express-

ed phenotypically in both thehomozygousandhet-

erozygousconditions (seerecessive).

Dysmorphic Features that differ from the ones generally

accepted in appearance.

Dystonia A neurological disorder associated with muscu-

lar spasms.

Edema An excessive accumulation of water in the inter-

cellular spaces.

Electrocardiogram (ECG) The record of the electrical

potentials associated with the spread of depolariza-

tion and repolarization through the muscle mass of

the heart during its beat cycle.

Emesis Seevomiting.

Endocardium The layer of smooth tissue lining the inside

of the chambers of the heart.

Endocrine diseases Diseases that arise from the over- or

under-production of hormones, or from resistance of

a target tissue to a particular hormone.

Endogenous A general term meaning originating from

within the body (compare withexogenous).

Envelope The lipid membrane that some viral particles

acquire as the viral particle leaves its host cell.

Enzyme immunohistochemistry The use of antibod-

ies labeled with an enzyme, such as horseradish

peroxidase or alkaline phosphatase. The binding of

theantibodyto itsantigencan be localized in cells

as the enzyme converts a colorless substrate into an

insoluble, colored compound that can be seen under

the microscope.

Eosinophil One of the three types ofpolymorphonuclear

leukocyte(seebasophilandneutrophil).

Epitopes Small regions of immunogenic molecules that

are specifically recognized by components of the

immune system.

Erythrocytes Red blood cells; anucleate cells rich in

hemoglobin that transport oxygen around the body.

Essential Nutrients that the body cannot make from

other compounds and must therefore be supplied in

GLOSSARY

mm^^ W^dad\nd[Y^hZVhZ