tubules branched and flattened sacs; two typcs are
distinguished: rough, wit\ ribosomcs attached, and
*nooth, which is smooth-surfaced (docs not contain
ribosomes)
cndooome (EN-doh-some) inttacellular vesicles
and tubular clements betwcen Golgi apparatus
and plasma membranel sorts and distributes vesicles
during endocytosis and exocltosis
cndotheltal cell sae endothelium
cndothelln-l (ET-f) (en-doh-THEEJin) one
mcmber of a family of peptides secreted by many
tissues that can act as a paracrinc or honnonal
signal; one major action is vasoconstriction
endothelium (en-doh-THEE-lee-um ) thin layer of
cells that lines heart cavities and blood vcssels
endothellum-derived daxing factor
(EDRF) nitric oxidc and possibly other substancesl
secretcd by vascular endothelium, it relaxes vascular
smooth muscle and causes arteriolar dilation
endothenn an animal that generatcs its own
internal body heat without having to rely on the
envifonment
end.plate pnftential (EPP) depolarization of motor
end plate ofskeletal muscle fiber in response to
acetylcholine; initiates action potential in muscle
plasma membrane
end-product lnhibition inhibition of a metabolic
pathway by final product's action upon allosteric site
on an enzyme (usually the rate-limiting enzyme) in
the pathway
end.syetolic volume (ESVI (sis-TAH-lik) amount
ofblood remaining in ventricle aftcr ejection
enkqrhalin (en-IGF-ah-lin) peptide neurotransmitter
at some synapsee activated by opiate drugs; an
cndogenous opioid
entef,lc nr:vous system (en-TAIR-ik) ncural network
residing in and inncrvating walls ofgastrointestinal
trAct
ntcrochromaffn-ttke (ECL) ccll histaminesecreting ccll ofthe stomach
enteroendocrlne cell cell locatcd in thc gastric gland
in thc stomach; sccretes gastritl
cnterogastrons (en-ter-oh-GAS-troncs) collective
term fbr hormones released by intestinal tlact;
inhibit stomach activity
nterchE adc c&culadon (en-tcr-oh-hih-PAT-ik)
reabsorption ofbile salts (and othcr substanccs)
tiom intestines, passage to liver (via hepatic portal
vcin), and secrction back to intestines (via bilc)
cnteroklnace (cn-ter-oh-I(fE-naoc) enzymc in
luminal plasma membranc of intestinal epithelial
cells; convcrts pancreatic trypsinogcn to trlpsin
cntralnment (cn-TRAIN-ment) adjusting biological
rhythrn to environmental cue$
cnz,yme (EN-zirne) protein catalyst that accelerates
specific chemical reactions but does not itself
undergo net chemical change during thc reaction
enzymc acdvlty rate at which snzymc converts
reactant to product; may be nreasure ofthe
properties ot'cnzl,me's activc sitc as altercd by
allostctic or covalent modulation; affccts rate of
enzyme-mediated reaction
eoslnophll (ee-oh-SIN-oh-fiI) polyrnorphonuclear
granulocytic leukocl'te whosc granules take up
red dye eosin; involved in parasite destruction and
allergic tesponses
ependymal cell (ep-END-ih-mel) rype of glial cell
that lines intcrnal cavities ofthe brain and produccs
cerebrospinal fluid
epicardium (cpp-ee-KAR-dee-um) layer of connectivc
tissue closely affixcd to outer surface ofthe heart
epidfdymte (cp-ih-DID-eh-mus) portion of
male reproductive duct system located between
seminiferous tubules and vas defbrcns
G.8
epiglottis (ep-ih-GlOT-iss) thin cartilage flap that
folds down, covering trachea, during swallowing
qfnqhrine (ep-ih-NEF-rin) aminc hormone
secreted by adrenal mcdulla and involved in
regulation of organic metabolism; a biogenic amine
(catecholamine) neuroffansmitter; also called
adrenaline
epiphyseal dosure (ep-ih-FlZ-ee-al) conversion of
epiphyseal growth plate to bone
epiphyseal growth plate actively proliferating
cartilage near bone ends; region ofbone growth
epiphysis (eh-PlF-ih-sis) end oflong bone
epithalamus a small portion of the dorsal posterior
diencephalon containing the pincal gland
qridrelial cell (ep-ih-THBE-lee-al) cell at surfhce
ofbody or hollow organ; specialized to secrete
or absorb ions and organic molecules; with other
epithelial cells, forms an epitheliwrn
qrithelial tieeue one of tJrc four major tissue rypes in
thc body, comprised ofaggregates ofcpithelial cells
epithellum (ep-ih-THEEJee-um) tissue that covers
all body surfaccs, lines all body cavities, and furms
mo$t glands
Eitolre (EP-ih-topc) antigenic portion of a moleculc
complexed to the MHC protein and presented to
tlre T cell; also called an d.ntiganic detarmi,nant
equitibdum (ce-quah-LlB -ree-um) no net change
occurs in a system; requircs no energy
equilibrium potendal gradicnt voltage across a
membrane that is equal in force but opposite in
directiou to concentration force affecting a givcn
ion species
erecdon penis or clitoris becoming stiffdue to
vascular congestion
erTthrccyt (eh-RlTH-roh-site) red blood cell
erythropoteste (eh-rith-roh-poy-EB-sis) erlthrocytc
production
erydroeotedn (eh-rith-roh-POY-ih-tin) peptide
hormone secreted mainly by kidney cells; stimuiates
red blood cell production; one ofthe hematopoietic
growth factors
esophaguc (eh-SOF-uh-gus) portion of digestive
tract that connects tfuoat (pharynx) and stomach
ecoential rmino acid amino acid that cannot be
formed by the body at all (or at a rate adequate
to meet metabolic requirements) and so must be
obtained from diet
essential nutrient substance required for normal or
optimal body firnction but synthesized by the body
either not at all or in amounts inadequate to prevent
disease
estradiol (es-tra-DYE-ol) steroid hormone of
estrogen family; major female sex hormone
estriol (ES-tree-ol) estrogen present in pregnancy;
excltatolT amino acid amino acid that
excitatorT 1rostsynaptic potential (EPSP) (postsin-NAP-tic) depolarizing graded potential in
postsl'naptic neuron in response to activation of
excitatory synapse
excitatory oynapse (SIN-aps) synapse that, when
activated, increases likelihood that postsynaptic
neuron will undergo action potentials or increases
flequency of existing action potentials
excitotodcity (cggs-SYE-toe-tocks-ih-city)
reproductive tract
eetrogen priming increase in responsiveness to
progcsterone caused by prior exposure to estrogcn
(e.9., in the uterus)
ectrone estrogen that is less prominent than estradiol
eukarTodc cell cell containing a membrane-enclosed
nucleus with genetic material; plant and animal cclls
eustachian tube (yoo-SMY-shce-an) duct
connecting thc middle ear with the nasopharytu
erraporation the loss ofbody water by pcrspiration,
resulting in cooling
exctabtltty ability to produce electrical signals
excitable membrane mcmbrane capable of
producin g action potentials
excitation *ontracdon coupllng in muscle fibcrs,
mechanism linking plasma membrane stimulation
with cross-bridgc force generation
spreading
damage to brain cells due to relcase ofglutamate
from ruptwed neurons
exocrine gland (BX-oh-krin) cluster of epithelial cells
specialized for secretion and having ducts that lcad
to an epithelial surflce
exocytoele (ex-oh-sye-TOH-sis ) process in which
intrace[ular vesiclc fuses with plasma membranc,
vesicle opens, and its contents are liberated into
extracellular fluid
exon (EX-on) DNA gene region containing code
words for a part ofthc amino acid sequence ofa
protein
eq'lradon (cx-pur-AY-shun)
movement of air out
oflungs
explratory rceerve volume (ERV) (excc) volume ofair that can be exhaled by
maxi
contraction ofexpiratory muscles after normal
resting expiration
extcnelon straightening a joint
external and sphlncter ring ofskeletal musdc
around lower end ofrectum
extemal audltoqf cand outer canal of the eu
between the pinna and the tympanic membranc
exter:nal envlronment environment
external surfhce ofan organism
external uretlual ephincter ring ofskeletal
tllat surrounds the urethra at base ofbladdcr
external work movemcnt ofexternal objects
skcletal muscle contraction
extracelftrlar fluld fluid outside cell;
and plasma
ext:acellular matrix (MAY-trix)
a complcx
consisting of a mixture of proteins (and, in
cases, minerals) interspersed with
ertrafrrsal fibet primary muscle fiber in
muscle, as opposed to modified (intafiud)
muscle spindle
extapyramidal system Jrt brainstcm
extdnslc pathway formation of fibrin
clots
pathway using tissue factor on cells in
once activated, it also recruits thc inffinric
pathway beyond factor XII
produced primarily by thc placenta
estrogen (ES-troh-jcn ) group of steroid hormones
that have effects similar to estradiol on female
acts as an
excitatory (depolarizing) neurotransmitter in the
nervous system
F
facilltated diffirsion
(
using a transporter to move moleculcs
to low concentration actoss a
requircd
F.actin the polymcrized form of actin
filaments
FAD flavin adenine dinucleotidc,
a
derived from the B-vitamin riboflavin
participates in transfer of hydrogen
metabolism
falloplan tube one oftwo tubes that
ovary to uterus
faet f,bcr skcletal muscle fiber that
hnving high AIPase activity
faet,glycolydc ffbet qpe of
skeletal
has high intrinsic contraction specd