Endocrine gland (EN-do-krin) A gland that secretes hormones into
interstitial fluid and then the blood; a ductless gland.
Endocrinology (en'-do-kri-NOL-o-je) The science concerned with the
structure and functions of endocrine glands and the diagnosis
and treatment of disorders of the endocrine system.
Endocytosis (en'-do-sT-TO-sis) The uptake into a cell of large mol-
ecules and particles in which a segment of plasma membrane
surrounds the substance, encloses it, and brings it in; includes
phagocytosis, bulk phase endocytosis, and receptor-mediated
Endoderm (EN-do-derm) A primary germ layer of the developing
embryo; gives rise to the gastrointestinal tract, urinary bladder,
urethra, and respiratory tract.
Endodontics (en'-do-DON-tiks) The branch of dentistry concerned
with the prevention, diagnosis, and treatment of diseases that
affect the pulp, root, periodontal ligament, and alveolar bone.
Endogenous (en-DOJ-e-nus) Growing from or beginning within the
Endolymph (EN-do-limf') The fluid within the membranous labyrinth
of the internal ear.
Endometrium (en'-do-MT-tre-um) The mucous membrane lining the
Endoplasmic reticulum (ER) (en'-do-PLAZ-mik re-TIK-u-lum) A network
of channels running through the cytoplasm of a cell that serves
in intracellular transportation, support, storage, synthesis, and
packaging of molecules. Portions of ER where ribosomes are
attached to the outer surface are called rough ER; portions that
have no ribosomes are called smooth ER.
Endorphin (en-DOR-fin) A neuropeptide in the central nervous sys-
tem that acts as a painkiller.
Endosteum (en-DOS-te-um) The membrane that lines the medullary
(marrow) cavity of bones, consisting of osteogenic cells and scat-
Endothelium (en'-do-THT-le-um) The layer of simple squamous
epithelium that lines the cavities of the heart, blood vessels, and
Energy The capacity to do work.
Enkephalin (en-KEF-a-lin) A peptide found in the central nervous
system that acts as a painkiller.
Enteric nervous system (EN-ter-ik) The part of the nervous system
that is embedded in the submucosa and muscularis of the gastro-
intestinal (GI) tract; governs motility and secretions of the GI tract.
Enzyme (EN-zTm) A substance that accelerates chemical reactions,
usually a protein.
Eosinophil (e'-o-SIN-o-fil) A type of white blood cell characterized by
granules that stain red or pink with acid dyes.
Ependymal cells (e-PEN-de-mal) Neuroglial cell that cover choroid
plexuses and produce cerebrospinal fluid (CSF); they also line the
ventricles of the brain and probably assist in the circulation of
Epicardium (ep'-i-KAR-de-um) The thin outer layer of the heart wall,
composed of serous tissue and mesothelium. Also called the
Epidemiology (ep'-i-de-me-OL-o-je) Study of the occurrence and
distribution of diseases and disorders in human populations.
Epidermis (ep-i-DERM-is) The superficial, thinner layer of skin, com-
posed of keratinized stratified squamous epithelium.
Epididymis (ep'-i-DID-i-mis) A comma-shaped organ that lies along
the posterior border of the testis and contains the ductus epi-
didymis, in which sperm undergo maturation.
P lu r a l is
Epidural space (ep'-i-DOO-ral) A space between the spinal dura
mater and the vertebral canal, containing areolar connective tis-
sue and a plexus of veins.
Epiglottis (ep'-i-GLOT-is) A large, leaf-shaped piece of elastic carti-
lage lying on top of the larynx, attached to the thyroid cartilage
and its unattached portion is free to move up and down to cover
the glottis (vocal folds and rima glottidis) during swallowing.
Epinephrine (ep-e-NEF-rin) Hormone secreted by the adrenal
medulla that produces actions similar to those that result from
sympathetic stimulation. Also called adrenaline (a-DREN-a-lin).
Epineurium (ep'-i-NOO-re-um) The superficial connective tissue
covering around an entire nerve.
Epiphyseal line (ep'-i-FIZ-e-al) The remnant of the epiphyseal plate in
the metaphysis of a long bone.
Epiphyseal plate (ep'-i-FIZ-e-al) The hyaline cartilage plate in the
metaphysis of a long bone; site of lengthwise growth of long
Epiphysis (e-PIF-i-sis) The end of a long bone, usually larger in diam-
eter than the shaft (diaphysis).
Episiotomy (e-piz'-e-OT-o-me) A cut made with surgical scissors to
avoid tearing of the perineum at the end of the second stage of
Epistaxis (ep'-i-STAK-sis) Loss of blood from the nose due to trauma,
infection, allergy, neoplasm, and bleeding disorders. Also called
Epithelial tissue (ep'-i-THE-le-al) The tissue that forms innermost and
outermost surfaces of body structures and forms the secreting
portion of glands.
Erectile dysfunction Failure to maintain an erection long enough for
sexual intercourse. Also known as impotence (IM-po-tens).
Erection (e-REK-shun) The enlarged and stiff state of the penis or
clitoris resulting from the engorgement of the spongy erectile
tissue with blood.
Erythema (er'-i-THE-ma) Skin redness usually caused by dilation of
Erythrocyte (e-RITH-ro-sTt) A mature red blood cell.
Erythropoiesis (e-rith'-ro-poy-E-sis) The process by which red blood
cells are formed.
Erythropoietin (e-rith'-ro-POY-e-tin) A hormone released by the
kidneys that stimulates red blood cell production.
Esophagus (e-SOF-a-gus) The hollow muscular tube that connects
the pharynx and the stomach.
Essential amino acids Those 10 amino acids that cannot be synthe-
sized by the human body at an adequate rate to meet its needs
and therefore must be obtained from the diet.