Glossary 571acidic molecules in the body or increases the loss of alka-
line molecules (Chapter 15).
Metabolic alkalosis(MET-uh-BAH-lik al-kah-LOH-sis)
A condition in which the blood pH is higher than nor-
mal, caused by any disorder that decreases the number of
acidic molecules in the body or increases the number of
alkaline molecules (Chapter 15).
Metabolism (muh-TAB-uh-lizm) All of the physical
changes and chemical reactions that take place within the
body; includes anabolism and catabolism (Chapter 1).
Metacarpals(MET-uh-KAR-puhls) The five long bones in
the palm of the hand (Chapter 6).
Metaphase(MET-ah-fayz) The second stage of mitosis, in
which the pairs of chromatids line up on the equator of
the cell (Chapter 3).
Metastasis(muh-TASS-tuh-sis) The spread of disease from
one part of the body to another (Chapter 3).
Metatarsals(MET-uh-TAR-suhls) The five long bones in
the arch of the foot (Chapter 6).
Microglia(my-kroh-GLEE-ah) A type of neuroglia capable
of movement and phagocytosis of pathogens (Chapter 8).
Micron(MY-kron) Old name for a micrometer (Chapter 3).
Micrometer(MY-kroh-mee-ter) A unit of linear measure
equal to one thousandth of a millimeter (0.001 mm)
(Chapter 3).
Microvilli(MY-kro-VILL-eye) Folds of the cell membrane
on the free surface of an epithelial cell; increase the sur-
face area for absorption (Chapter 3).
Micturition(MIK-tyoo-RISH-un) Urination; the voiding
or elimination of urine from the urinary bladder
(Chapter 18).
Midbrain(MID-brayn) The part of the brain between the
pons and hypothalamus; regulates visual, auditory, and
righting reflexes (Chapter 8).
Mineral(MIN-er-al) An inorganic element or compound;
many are needed by the body for normal metabolism and
growth (Chapter 17).
Mineralocorticoids (MIN-er-al-oh-KOR-ti-koidz) The
hormones secreted by the adrenal cortex that affect
fluid–electrolyte balance; aldosterone is the major hor-
mone in this group (Chapter 10).
Minute respiratory volume(MIN-uht RES-pi-rah-TOR-
ee VAHL-yoom) The volume of air inhaled and exhaled
in 1 minute; calculated by multiplying tidal volume by
number of respirations per minute (Chapter 15).
Mitochondria(MY-toh-KAHN-dree-ah) The cell orga-
nelles in which aerobic cell respiration takes place and
energy (ATP) is produced; found in the cytoplasm of a
cell (Chapter 3).
Mitosis (my-TOH-sis) The process of cell division in
which one cell with the diploid number of chromosomes
divides once to form two identical cells, each with the
diploid number of chromosomes (Chapter 3).Mitral valve(MY-truhl VALV) The left AV valve (bicuspid
valve), which prevents backflow of blood from the left
ventricle to the left atrium when the ventricle contracts
(Chapter 12).
Mixed nerve(MIKSD NERV) A nerve that contains both
sensory and motor neurons (Chapter 8).
Molecule(MAHL-e-kuhl) A chemical combination of two
or more atoms (Chapter 2).
Monocyte (MAH-no-sight) A type of white blood cell
(agranular); differentiates into a macrophage, which is
capable of phagocytosis of pathogens and dead or dam-
aged cells (Chapter 11).
Monosaccharide(MAH-noh-SAK-ah-ride) A carbohy-
drate molecule that is a single sugar; includes the hexose
and pentose sugars (Chapter 2).
Morula(MOR-yoo-lah) An early stage of embryonic devel-
opment, a solid sphere of cells (Chapter 21).
Motility(moh-TILL-e-tee) The ability to move (Chapter
3).
Motion sickness(MOH-shun) Queasiness that accompa-
nies repetitive or unexpected motion (Chapter 9).
Motor area(MOH-ter) Part of the cerebral cortex of the
frontal lobe; generates the impulses necessary for volun-
tary movement (Chapter 7).
Motor neuron(MOH-ter NYOOR-on) A nerve cell that
carries impulses from the central nervous system to an
effector (Syn.—efferent neuron) (Chapter 8).
Mucosa (mew-KOH-suh) A mucous membrane, the
epithelial lining of a body cavity that opens to the envi-
ronment (Chapter 4).
Mucous membrane (MEW-kuss MEM-brayn) The
epithelial tissue lining of a body tract that opens to the
environment (Chapter 4).
Mucus(MEW-kuss) The thick fluid secreted by mucous
membranes or mucous glands (Chapter 4).
Multicellular (MULL-tee-SELL-yoo-lar) Consisting of
more than one cell; made of many cells (Chapter 4).
Multiple sclerosis(MULL-ti-puhl skle-ROH-sis) A pro-
gressive nervous system disorder, an autoimmune dis-
ease, characterized by the degeneration of the myelin
sheaths of CNS neurons (Chapter 8).
Muscle fatigue(MUSS-uhl fah-TEEG) The state in which
muscle fibers cannot contract efficiently, due to a lack of
oxygen and the accumulation of lactic acid (Chapter 7).
Muscle fiber(MUSS-uhl FYE-ber) A muscle cell (Chapter
7).
Muscle sense(MUSS-uhl SENSE) The conscious or
unconscious awareness of where the muscles are, and
their degree of contraction, without having to look at
them (Chapter 7).
Muscle tissue(MUSS-uhl TISH-yoo) The tissue special-
ized for contraction and movement of parts of the body
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