972
GLOSSARY
skeletal muscle
(skel
′
e
˘-tal mus
′
l)
Type
of voluntary muscle tissue in
muscles attached to bones. p. 14
sliding f
lament model
(slı¯
′
ding F l
′
eh-
ment ma
′
dul)
Muscles contract
when the thin (actin) and thick
(myosin) F
laments move past each
other, shortening the skeletal muscle
cells. p. 291
small intestine
(smawl in-tes
′
tin)
Part
of the digestive tract extending from
the stomach to the cecum; consisting
of the duodenum, jejunum, and
ileum. p. 678
smooth muscle
(smoo-th mus
′
l)
Type
of involuntary muscle tissue in the
walls of hollow viscera; visceral
muscle. p. 163
sodium pump
(so
′
de-um pump)
Active transport mechanism that
concentrates sodium ions outside a
cell membrane. p. 365
solute
(sol
′
u
¯t)
Chemical dissolved in a
solution. p. 92
solution
(so-lu
′
shun)
Homogenous
mixture of chemicals (solutes) in a
dissolving medium (solvent). p. 92
solvent
(sol
′
vent)
Liquid portion of
a solution in which a solute is
dissolved. p. 92
somatic cell
(so-mat
′
ik sel)
Any cell of
the body other than the sex cells.
p. 100
somatic nervous system
(so-mat
′
-ik
ner
′
vus sis
′
tem)
Motor pathways
of the peripheral nervous system
that lead to the skin and skeletal
muscles. p. 411
somatostatin
(so-mat
′
o-sta
′
tin)
Hormone secreted by the pancreatic
islets that inhibits the release of
growth hormone. p. 511
somatotropin
(so
″
mah-to-tro
′
pin)
Growth hormone. p. 494
special sense
(spesh
′
al sens)
Sense
that stems from receptors
associated with specialized sensory
organs, such as the eyes and ears.
p. 438
species resistance
(spe
′
se
¯z re-zis
′
tans)
Natural ability of one type of
organism to resist infection by
pathogens that cause disease in
another type of organism. p. 626
spermatic cord
(sper-mat
′
ik kord)
Structure consisting of blood vessels,
nerves, the ductus deferens, and other
vessels extending from the abdominal
inguinal ring to the testis. p. 835
spermatid
(sper
′
mah-tid)
Intermediate
stage in sperm cell formation. p. 836
spermatocyte
(sper-mat
′
o-sı¯t)
Early
stage in sperm cell formation.
p. 836
serotonin
(se
″
ro-to
′
nin)
Vasoconstrictor
that blood platelets release when
blood vessels break, controlling
bleeding. Also a neurotransmitter.
p. 443
serous cell
(se
′
rus sel)
Glandular cell
that secretes a watery fl
uid (serous
fl
uid) with a high enzyme content.
p. 152
serous fl
uid
(se
′
rus fl
oo
′
id)
Secretion of
a serous membrane. p. 152
serous membrane
(se
′
rus mem
′
bra
¯n)
Membrane that lines a cavity
without an opening to the outside of
the body. p. 12
serum
(se
′
rum)
±luid portion of
coagulated blood. p. 541
sesamoid bone
(ses
′
ah-moid bo
¯n)
Round bone within tendons adjacent
to joints. p. 193
set point
(set point)
Target value of a
physiological measure maintained
automatically in the body. p. 9
sex chromosome
(seks kro
′
mo-so
¯m)
Chromosome that carries genes
responsible for the development
of characteristics associated with
maleness or femaleness; an X or Y
chromosome. p. 919
sex-infl
uenced inheritance
(seks-in
′
fl oo-
enst in-her
′
ı˘-tens)
Transmission
of a trait dominant in one sex but
recessive in the other. p. 928
sex-limited inheritance
(seks
′
-lim
′
it-ed
in-her
′
ı˘-tens)
Transmission of a trait
expressed in one sex only. p. 928
sexually transmitted inFection
(sek
′
shoo-
ah-le trans-mi
′
ted in-fek
′
shun)
Infection transmitted from one
individual to another by direct
contact during sexual activity. p. 867
sigmoid colon
(sig
′
moid ko
′
lon)
S
-shaped part of the large intestine
between the descending colon and
the rectum. p. 687
signal transduction
(sig
′
nahl trans-
duk
′
shun)
Series of biochemical
reactions that allows cells to receive
and respond to messages coming in
through the cell membrane. p. 79
simple sugar
(sim
′
pl shoog
′
ar)
Monosaccharide. p. 62
single nucleotide polymorphism
(sing
′
el
nu
′
kle-o-tı¯d pol
″
e-mor
′
F z-em)
A
variant base at a particular place in
the genome that occurs in at least
1% of a population. p. 135
sinoatrial node
(si
″
no-a
′
tre-al no
¯d)
Specialized tissue in the wall of the
right atrium that initiates cardiac
cycles; the pacemaker; SA node.
p. 565
sinus
(si
′
nus)
Cavity or space in a bone
or other body part. p. 738
secretin
(se-kre
′
tin)
Hormone from the
small intestine that stimulates the
pancreas to release pancreatic juice.
p. 672
secretion
(se-kre
′
shun)
Substance
produced in and released from a
gland cell. p. 150
segmentation
(seg
′′
men-ta
′
shun)
Alternating contraction and
relaxation of circular muscle F
bers
that propels chyme through the
intestines. p. 654
selectively permeable
(se-le
˘k
′
tiv-le
per
′
me-ah-b
′
l)
Membrane that
allows some types of molecules
through but not others. p. 79
semen
(se
′
men)
±luid containing sperm
cells and secretions discharged
from the male reproductive tract at
ejaculation. p. 841
semicircular canal
(sem
″
ı˘-ser
′
ku-lar
kah-nal
′
)
Tubular structure in the
inner ear that contains the receptors
providing the sense of dynamic
equilibrium. p. 453
seminal vesicle
(sem
″
ı˘-nal ves
′
ı˘-kel)
One of a pair of pouches that adds
fructose and prostaglandins to sperm
as semen forms. p. 840
seminiFerous tubule
(sem
″
ı˘-nif
′
er-us
tu
′
bu
¯l)
Tubule within the testes
where sperm cells form. p. 835
senescence
(se
˘-nes
′
ens)
Aging. p. 907
sensation
(sen-sa
′
shun)
A feeling
resulting from the brain
′
s
interpretation of sensory nerve
impulses. p. 438
sensory adaptation
(sen
′
so-re ad
″
ap-
ta
′
shun)
Sensory receptors
becoming unresponsive or inhibition
along the CNS pathways leading
to sensory regions of the cerebral
cortex after constant repeated
stimulation. p. 440
sensory area
(sen
′
so-re a
′
re-ah)
Part of
the cerebral cortex that receives and
interprets sensory nerve impulses.
p. 401
sensory nerve
(sen
′
so-re nerv)
Nerve
composed of sensory nerve F
bers.
p. 412
sensory neuron
(sen
′
so-re nu
′
ron)
Neuron that transmits an impulse
from a receptor to the central
nervous system. p. 360
sensory receptor
(sen
′
so-re re
″
sep
′
tor)
Specialized structure associated
with the peripheral end of a
sensory neuron speciF
c to
detecting a particular sensation
and triggering a nerve impulse in
response. p. 355
serosa
(se
¯r-o
′
sah)
Outer covering of the
alimentary canal. p. 654
