in the diet (seeessential fatty acids, compare with
non-essential).Essential fatty acids Fatty acids that must be supplied in
the diet since humans lack the enzymes necessary to
produce them.
Estimated average requirement (EAR) The mean daily
amount of nutrient (or energy) thought to be needed
by a population (compare with lower reference
nutrient intake,reference nutrient intakeandsafe
intake).
Euploidy The situation in which the number of chromo-
somes is an exact multiple of thehaploidnumber (see
aneuploidy,polyploidy).
Exogenous A general term meaning originating outside
the body (compare withendogenous).
Exons Coding sequences of bases found within a gene that
are separated by intervening noncoding sequences
called introns.
Exophthalmos Protruding eyeballs.
Extended spectrum A-lactamases (ESBLs) Enzymes pro-
duced by certain bacteria, for exampleKlebsiellaspp,
E. coli, that can hydrolyze extended spectrum cepha-
losporins (antibiotics).
Extractable nuclear antigens (ENA) Antigens that lead
to the formationof autoantibodies in certain diseases
such as rheumatoid arthritis and systemic lupus ery-
thematosus (seeantinuclear factors).
Extravascular hemolysis The uptake and subsequent
destruction of antibody-coated erythrocytes in the
spleen and liver (see alsoimmune adherence).
Fainting Common term forsyncope.
Familial hypercholesterolemia An autosomaldominant
condition with a frequency of 1 in 500 that affects
heterozygotes; associated with defective receptors for
LDL on the liver cells.
Favism The hemolytic crisis brought on by the consump-
tion of fava or broad beans (Vicia fava) in persons
with G6PDH deficiency.
Fistula An abnormal passage from a cavity or tube to
another cavity or free surface.
Fluorosis The mottling of the teeth as they form in the
jaws caused by fluoride in drinking water at concen-
trations greater than 12 ppm.
Fragile sites Particular regions of chromosomes that are
susceptible to breakage when the cells are cultured in
the absence of certain chemicals such as folic acid.
Fulminant cholera The massive leakage of intracel-
lular water into the gastrointestinal tract and the
subsequentdiarrheafollowing infection withVibrio
cholerae.Galactorrhea An inappropriate secretion of milk.See also
amenorrheaandoligomenorrhea.Gene mutation theory of aging This suggests that an
accumulation of mutations during the course of life
leads ultimately to tissue and organ malfunctions and
eventually death.Genetic diseases Diseases that arise due to defects in the
genes or chromosomes.Genetic imprinting A condition that depends upon
whether paternal or maternal inheritance of a trait
has occurred.Genotype The genetic or hereditary constitution of an
individual. The term can also be applied to any par-
ticular pair of alleles that an individual possesses at
a specific locus on a chromosome (contrast with
phenotype).Glossitis Inflammationof the tongue.Graft versus host disease (GVHD) The condition associ-
ated with the transfusion of whole blood, blood prod-
ucts or bone marrow particularly to an immunode-
ficient patient, which contain residual lymphocytes.
Thesmall lymphocytespresent in the donated blood
recognize theimmunogensof the recipient as foreign
and mount an immune response. The donor lym-
phocytes proliferate in the patient and attack tissues.Gummas Tumor-like growths of a rubbery consistency
that some patients develop in benign late syphilis.Gynecomastia The development of enlarged breasts in
males.Haploid (N) The presence of half thediploidnumber of
chromosome (compare withdiploid).Health The state of physical, mental and social well-being;
not merely the absence of disease.Heart attack Seemyocardial infarction.Helminths Parasitic worms such as nematodes, cestodes
and trematodes.Helper T lymphocytes SeeTH cells.Hematemesis The presence of blood in vomit.Hematology The study of blood and its disorders.Hemoglobinopathies Clinical conditions that result from
mutations in the genes for globin molecules.Hemolysis The rupture or lysis of erythrocytes and
release of their hemoglobin.GLOSSARYCZhhVg6]bZY!BVjgZZc9Vlhdc!8]g^hHb^i]:YLddY mm^^^