576 GlossaryPentose sugar(PEN-tohs) A five-carbon sugar (monosac-
charide) that is a structural part of the nucleic acids
DNA, RNA, and ATP (Chapter 2).
Pepsin(PEP-sin) The enzyme found in gastric juice that
begins protein digestion; secreted by chief cells (Chapter
16).
Peptidases(PEP-ti-day-ses) Digestive enzymes that break
down polypeptides to amino acids; secreted by the small
intestine (Chapter 16).
Peptide bond(PEP-tyde) A chemical bond that links two
amino acids in a protein molecule (Chapter 2).
Pericardium (PER-ee-KAR-dee-um) The three mem-
branes that enclose the heart, consisting of an outer
fibrous layer and two serous layers (Chapter 12).
Perichondrium (PER-ee-KON-dree-um) The fibrous
connective tissue membrane that covers cartilage
(Chapter 4).
Perilymph(PER-i-limf) The fluid in the bony labyrinth of
the inner ear (Chapter 9).
Periodontal membrane (PER-ee-oh-DON-tal) The
membrane that lines the tooth sockets in the upper and
lower jaws; produces a bone-like cement to anchor the
teeth (Chapter 16).
Periosteum(PER-ee-AHS-tee-um) The fibrous connec-
tive tissue membrane that covers bone; contains
osteoblasts for bone growth or repair (Chapter 4).
Peripheral(puh-RIFF-uh-ruhl) Extending from a main
part; closer to the surface (Chapter 1).
Peripheral nervous system(puh-RIFF-uh-ruhl NERV-
vuhs) The part of the nervous system that consists of the
cranial nerves and spinal nerves (Chapter 8).
Peripheral resistance(puh-RIFF-uh-ruhl ree-ZIS-tense)
The resistance of the blood vessels to the flow of blood;
changes in the diameter of arteries have effects on blood
pressure (Chapter 13).
Peristalsis(per-i-STALL-sis) Waves of muscular contrac-
tion (one-way) that propel the contents through a hollow
organ (Chapter 2).
Peritoneum(PER-i-toh-NEE-um) The serous membrane
that lines the abdominal cavity (Chapter 1).
Peritonitis(per-i-toh-NIGH-tis) Inflammation of the peri-
toneum (Chapter 16).
Peritubular capillaries(PER-ee-TOO-byoo-ler) The cap-
illaries that surround the renal tubule and receive the
useful materials reabsorbed from the renal filtrate; carry
blood from the efferent arteriole to the renal vein
(Chapter 18).
Pernicious anemia(per-NISH-us uh-NEE-mee-yah) An
anemia that is the result of a deficiency of vitamin B 12 or
the intrinsic factor (Chapter 11).
Peyer’s patches (PYE-erz) The lymph nodules in the
mucosa of the small intestine, especially in the ileum
(Chapter 14).
pHA symbol of the measure of the concentration of hydro-gen ions in a solution. The pH scale extends from 0–14,
with a value of 7 being neutral. Values lower than 7
are acidic; values higher than 7 are alkaline (basic)
(Chapter 2).
Phagocytosis (FAG-oh-sigh-TOH-sis) The process by
which a moving cell engulfs a particle; especially, the
ingestion of microorganisms by white blood cells
(Chapter 3).
Phalanges(fuh-LAN-jees) The long bones of the fingers
and toes. There are 14 in each hand or foot (from the
Latin “line of soldiers”) (Chapter 6).
Phantom pain(FAN-tum PAYN) Pain following amputa-
tion of a limb that seems to come from the missing limb
(Chapter 9).
Pharynx(FA-rinks) A muscular tube located behind the
nasal and oral cavities; a passageway for air and food
(Chapter 15).
Phenotype(FEE-noh-type) The appearance of the individ-
ual as related to genotype; the expression of the genes
that are present (Chapter 21).
Phlebitis(fle-BY-tis) Inflammation of a vein (Chapter 13).
Phospholipid(FOSS-foh-LIP-id) An organic compound in
the lipid group that is made of one glycerol, two fatty
acids, and a phosphate molecule; forms the bilayer of cell
membranes (Chapter 2).
Phrenic nerves(FREN-ik NERVZ) The pair of peripheral
nerves that are motor to the diaphragm (Chapter 15).
Physiology(FIZZ-ee-AH-luh-jee) The study of the func-
tioning of the body and its parts (Chapter 1).
Pia mater(PEE-ah MAH-ter) The innermost layer of the
meninges, made of thin connective tissue on the surface
of the brain and spinal cord (Chapter 8).
Pilomotor muscle(PYE-loh-MOH-ter) A smooth muscle
attached to a hair follicle; contraction pulls the follicle
upright, resulting in “goose bumps” (Syn.—arrector pili
muscle) (Chapter 5).
Pineal gland(PIN-ee-uhl) An endocrine gland on the pos-
terior wall of the third ventricle of the brain; secretes
melatonin (Chapter 10).
Pinocytosis(PIN-oh-sigh-TOH-sis) The process by which
a stationary cell ingests very small particles or a liquid
(Chapter 3).
Pituitary gland(pi-TOO-i-TER-ee) An endocrine gland
located below the hypothalamus, consisting of anterior
and posterior lobes (Syn.—hypophysis) (Chapter 10).
Pivot joint(PI-vot) A diarthrosis that permits rotation
(Chapter 6).
Placenta(pluh-SEN-tah) The organ formed in the uterus
during pregnancy, made of both fetal and maternal tissue;
the site of exchanges of materials between fetal blood and
maternal blood (Chapter 13).
Plane(PLAYN) An imaginary flat surface that divides the
body in a specific way (Chapter 1).
Plasma(PLAZ-mah) The water found within the blood30Scanlon(p3) Glossary 8/17/06 11:08 AM Page 576