580 Glossaryloop of Henle, distal convoluted tubule, and collecting
tubule; the site of tubular reabsorption and tubular secre-
tion (Chapter 18).
Renal vein(REE-nuhl VAYN) The vein that returns blood
from a kidney to the inferior vena cava (Chapter 18).
Renin-angiotensin mechanism(REE-nin AN-jee-oh-
TEN-sin) A series of chemical reactions initiated by a
decrease in blood pressure that stimulates the kidneys to
secrete the enzyme renin; culminates in the formation of
angiotensin II (Chapter 10).
Repolarization(RE-pol-lahr-i-ZAY-shun) The restoration
of electrical charges on either side of a cell membrane
following depolarization; positive charge outside and a
negative charge inside brought about by a rapid outflow
of potassium ions (Chapter 7).
Reproductive system (REE-proh-DUK-tive SIS-tem)
The male or female organ system that produces gametes,
ensures fertilization, and in women, provides a site for
the developing embryo-fetus (Chapter 20).
Reservoir(REZ-er-vwor) 1. A person or animal who har-
bors a pathogen and is a source of the pathogen for oth-
ers (Chapter 22). 2. A storage site (Chapter 7).
Resident flora(REZ-i-dent FLOOR-uh) Part of normal
flora; those microorganisms on or in nearly everyone in
specific body sites nearly all the time (Chapter 22).
Residual air(ree-ZID-yoo-al) The volume of air that
remains in the lungs after the most forceful exhalation;
important to provide for continuous gas exchange; aver-
age: 1000–1500 mL (Chapter 15).
Resistance(re-ZIS-tenss) The total of all of the body’s
defenses against pathogens; includes the non-specific
aspects of innate immunity such as unbroken skin and the
specific mechanisms of adaptive immunity such as anti-
body production (Chapter 22).
Resorption(ree-ZORP-shun) The process of removal by
absorption, such as the removal of bone matrix by osteo-
clasts (Chapter 6).
Respiratory acidosis(RES-pi-rah-TOR-ee ass-i-DOH-
sis) A condition in which the blood pH is lower than nor-
mal, caused by disorders that decrease the rate or
efficiency of respiration and permit the accumulation of
carbon dioxide (Chapter 15).
Respiratory alkalosis(RES-pi-rah-TOR-ee al-kah-LOH-
sis) A condition in which the blood pH is higher than
normal, caused by disorders that increase the rate of res-
piration and decrease the level of carbon dioxide in the
blood (Chapter 15).
Respiratory pump(RES-pi-rah-TOR-ee) A mechanism
that increases venous return; pressure changes during
breathing compress the veins that pass through the tho-
racic cavity (Chapter 13).
Respiratory system(RES-pi-rah-TOR-ee SIS-tem) The
organ system that moves air into and out of the lungs so
that oxygen and carbon dioxide may be exchanged
between the air and the blood (Chapter 15).Resting potential(RES-ting poh-TEN-shul) The differ-
ence in electrical charges on either side of a cell mem-
brane not transmitting an impulse; positive charge
outside and a negative charge inside (Chapter 7).
Reticulocyte(re-TIK-yoo-loh-sight) A red blood cell that
contains remnants of the endoplasmic reticulum, an
immature stage in red blood cell formation; makes up
about 1% of the red blood cells in peripheral circulation
(Chapter 11).
Reticuloendothelial system (re-TIK-yoo-loh-en-doh-
THEE-lee-al) Former name for the tissue macrophage
system, the organs or tissues that contain macrophages
(RE cells) that phagocytize old red blood cells; the liver,
spleen, and red bone marrow (Chapter 11).
Retina(RET-i-nah) The innermost layer of the eyeball that
contains the photoreceptors, the rods and cones (Chap-
ter 9).
Retroperitoneal(RE-troh-PER-i-toh-NEE-uhl) Located
behind the peritoneum (Chapter 18).
Reuptake(ree-UP-tayk) The reabsorption of a substance
that was just secreted; used with respect to some neuro-
transmitters (Chapter 8).
Rh factor(R-H FAK-ter) The red blood cell types deter-
mined by the presence or absence of the Rh (D) antigen
on the red blood cell membranes; the two types are Rh
positive and Rh negative (Chapter 11).
Rheumatoid arthritis (ROO-muh-toyd ar-THRY-tiss)
Inflammation of a joint; an autoimmune disease. The
joint damage may progress to fusion and immobility of
the joint (Chapter 6).
Rhodopsin(roh-DOP-sin) The chemical in the rods of
the retina that breaks down when light waves strike
it; this chemical change initiates a nerve impulse
(Chapter 9).
RhoGAM(ROH-gam) The trade name for the Rh (D)
antibody administered to an Rh-negative woman who has
delivered an Rh-positive infant; it will destroy any fetal
red blood cells that may have entered maternal circula-
tion (Chapter 11).
Ribosome(RYE-boh-sohme) A cell organelle found in the
cytoplasm; the site of protein synthesis (Chapter 3).
Ribs(RIBZ) The 24 flat bones that, together with the ster-
num, form the rib cage. The first seven pairs are true
ribs, the next three pairs are false ribs, and the last two
pairs are floating ribs (Chapter 6).
Rickets(RIK-ets) A deficiency of vitamin D in children,
resulting in poor and abnormal bone growth (Chapter 6).
RNA (Ribonucleic acid)A nucleic acid that is a single
strand of nucleotides; essential for protein synthesis
within cells; messenger RNA (mRNA) is a copy of the
genetic code of DNA; transfer RNA (tRNA) aligns amino
acids in the proper sequence on the mRNA (Chapter 2).
Rods(RAHDZ) The sensory receptors in the retina of the
eye that detect the presence of light (Chapter 9).
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