Glossary
G-17
Parkinson’s disease
Neurodegenerative disorder of the basal nuclei due
to insufficient secretion of the neurotransmitter dopamine; symptoms
include tremor and rigid movement.
Partial pressure
Te pressure exerted by a single component of a mix-
ture of gases.
Parturition
(par
0
tu-rish
9
un) Culmination of pregnancy; giving birth.
Passive immunity
Short-lived immunity resulting from the introduc-
tion of “borrowed antibodies” obtained from an immune animal or hu-
man donor; immunological memory is not established.
Passive (transport) processes
Membrane transport processes that do
not require cellular energy (A±P), e.g., diffusion, which is driven by ki-
netic energy.
Pathogen
(path
9
o-jen) Disease-causing organism.
Pectoral
(pek
9
tor-al) Pertaining to the chest.
Pectoral (shoulder) girdle
Bones that attach the upper limbs to the axial
skeleton; includes the clavicle and scapula.
Pedigree
±races a particular genetic trait through several generations
and helps predict the genotype of future offspring.
Pelvic girdle (hip girdle)
Consists of the paired coxal bones and sacrum
that attach the lower limbs to the axial skeleton.
Pelvis
(pel
9
vis) (1) Basin-shaped bony structure composed of the pelvic
girdle, sacrum, and coccyx; (2) funnel-shaped tube within the kidney
continuous with the ureter.
Penis
(pe
9
nis) Male organ of copulation and urination.
Pepsin
Enzyme capable of digesting proteins in an acid pH.
Peptide bond
(pep
9
tīd) Bond joining the amine group of one amino acid
to the acid carboxyl group of a second amino acid with the loss of a water
molecule.
Perforating canals
Canals that run at right angles to the long axis of the
bone, connecting the vascular and nerve supplies of the periosteum to
those of the central canals and medullary cavity; also called Volkmann’s
canals.
Pericardium
(per
0
ĭ-kar
9
de-um) Double-layered sac enclosing the heart
and forming its superficial layer; has fibrous and serous layers.
Perichondrium
(per
0
ĭ-kon
9
dre-um) Fibrous, connective-tissue mem-
brane covering the external surface of cartilaginous structures.
Perimysium
(per
0
ĭ-mis
9
e-um) Connective tissue that bundles muscle
fibers into fascicles.
Perineum
(per
0
ĭ-ne
9
um) Tat region of the body spanning the region
between the ischial tuberosities and extending from the pubic arch to the
coccyx.
Periosteum
(per
0
e-os
9
te-um) Double-layered connective tissue that cov-
ers and nourishes the bone.
Peripheral congestion
Condition caused by failure of the right side of
the heart; results in edema in the extremities.
Peripheral nervous system (PNS)
Portion of the nervous system con-
sisting of nerves and ganglia that lie outside of the brain and spinal cord.
Peripheral resistance
A measure of the amount of friction encountered
by blood as it flows through the blood vessels.
Peristalsis
(per
0
ĭ-stal
9
sis) Progressive, wavelike contractions that move
foodstuffs through the alimentary tube organs (or that move other sub-
stances through other hollow body organs).
Peritoneum
(per
0
ĭ-to-ne
9
um) Serous membrane lining the interior of
the abdominal cavity and covering the surfaces of abdominal organs.
Peritonitis
(per
0
ĭ-to-ni
9
tis) Inflammation of the peritoneum.
Osteoid
(os
9
te-oid) Unmineralized bone matrix.
Osteomalacia
(os
0
te-o-mah-la
9
she-ah) Disorder in which bones are in-
adequately mineralized; so² bones.
Osteon
(os
9
te-on) System of interconnecting canals in the microscopic
structure of adult compact bone; unit of bone; also called Haversian system.
Osteoporosis
(os
0
te-o-po-ro
9
sis) Decreased density and strength of bone
resulting from a gradual decrease in rate of bone formation.
Ovarian cycle
(o-vayr
9
e-an) Monthly cycle of follicle development, ovu-
lation, and corpus luteum formation in an ovary.
Ovary
(o
9
var-e) Female reproductive organ in which ova (eggs) are pro-
duced; female gonad.
Ovulation
(ov
0
u-la
9
shun) Ejection of an immature egg (oocyte) from the
ovary.
Ovum
(o
9
vum) Female gamete; egg.
Oxidases
Enzymes that catalyze the transfer of oxygen in oxidation-
reduction reactions.
Oxidation
(oks
9
ĭ-da
0
shun) Process of substances combining with oxy-
gen or the removal of hydrogen.
Oxidation-reduction (redox) reaction
A reaction that couples the
oxidation (loss of electrons) of one substance with the reduction (gain of
electrons) of another substance.
Oxidative phosphorylation
(ok
9
sĭ-da
0
tiv fos
0
for-ĭ-la
9
shun) Process of
A±P synthesis during which an inorganic phosphate group is attached to
ADP; occurs via the electron transport chain within the mitochondria.
Oxyhemoglobin
(ok
0
sĭ-he
0
mo-glo
9
bin) Oxygen-bound form of
hemoglobin.
Oxytocin
(ok
0
sĭ-to
9
sin) Hormone synthesized in the hypothalamus and
secreted by the posterior pituitary; stimulates contraction of the uterus
during childbirth and the ejection of milk during nursing.
Paget’s disease
(paj
9
ets) Disorder characterized by excessive bone break-
down and abnormal bone formation.
Palate
(pal
9
at) Roof of the mouth.
Pancreas
(pan
9
kre-us) Gland located behind the stomach, between the
spleen and the duodenum; produces both endocrine and exocrine secretions.
Pancreatic juice
(pan
0
kre-at
9
ik) Bicarbonate-rich secretion of the pan-
creas containing enzymes for digestion of all food categories.
Papilla
(pah-pil
9
ah) Small, nipple-like projection; e.g., dermal papillae
are projections of dermal tissue into the epidermis.
Paracrine
(par
9
ah-krin) A chemical messenger that acts locally within
the same tissue and is rapidly destroyed. Examples are prostaglandins
and nitric oxide.
Parasagittal planes
All sagittal planes offset from the midline.
Parasympathetic division
Te division of the autonomic nervous sys-
tem that oversees digestion, elimination, and glandular function; the rest-
ing and digesting subdivision.
Parasympathetic tone
Normal (background) level of parasympathetic
output; sustains normal gastrointestinal and urinary tract activity, lowers
heart rate.
Parathyroid glands
(par
0
ah-thi
9
roid) Small endocrine glands located on
the posterior aspect of the thyroid gland.
Parathyroid hormone (PTH)
Hormone released by the parathyroid
glands that regulates blood calcium level.
Parietal
(pah-ri
9
ĕ-tal) Pertaining to the walls of a cavity.
Parietal serosa
Te part of the double-layered membrane that lines the
walls of the ventral body cavity.
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