kle-o-tīd) Building block of nucleic acids; consists of a
sugar, a nitrogen-containing base, and a phosphate group.
kle-is) (1) Control center of a cell; contains genetic mate-
rial; (2) clusters of nerve cell bodies in the CNS.
Chemical substances taken in via the diet that are used for
energy and cell building.
A cut made diagonally between the horizontal and ver-
tical plane of the body or an organ.
zhun) Closure or obstruction.
Octet rule (rule of eights)
) Te tendency of atoms to interact in
such a way that they have eight electrons in their valence shell.
dro-sīt) A type of CNS supporting cell
that composes myelin sheaths.
o-sīt) Immature female gamete.
ĕ-sis) Process of ovum (female gamete) formation.
mik) Pertaining to the eye.
tik) Pertaining to the eye or vision.
muh) Te partial crossover of ﬁbers of the
A part of the body formed of two or more tissues and adapted to
carry out a speciﬁc function; e.g., the stomach.
A group of organs that work together to perform a vital
body function; e.g., the nervous system.
) Small cellular structures (ribosomes, mito-
chondria, and others) that perform speciﬁc metabolic functions for the
cell as a whole.
Any compound composed of atoms (some of which
are carbon) held together by covalent (shared electron) bonds.
Pertaining to carbon-containing molecules, such as proteins,
fats, and carbohydrates.
Te living animal (or plant), which represents the sum total of
all its organ systems working together to maintain life.
Attachment of a muscle that remains relatively ﬁxed during mus-
Te number of solute particles dissolved in 1 kilogram
(1000 g) of water; reﬂects the solution’s ability to cause osmosis.
ĭ-te) Te number of solute particles present in
1 liter of a solution.
tor) Structure sensitive to osmotic pres-
sure or concentration of a solution.
sis) Diﬀusion of a solvent through a membrane from a
dilute solution into a more concentrated one.
A measure of the tendency of water to move into a
more concentrated solution.
te-o-blasts) Bone-forming cells.
te-o-klasts) Large cells that resorb or break down bone
te-o-sīt) Mature bone cell.
e-sis) Te process of bone formation; also
Fetal structure that gives rise to the brain, spinal cord, and
associated neural structures; formed from ectoderm by day 23 of embry-
le-ah) Nonexcitable cells of neural tissue that sup-
port, protect, and insulate the neurons; glial cells.
ĭ-sis) Posterior pituitary plus infun-
dibulum; portion of the pituitary gland derived from the brain.
Region where a motor neuron comes into
close contact with a skeletal muscle cell.
Neuron (nerve cell)
ron) Cell of the nervous system specialized to
generate and transmit electrical signals (action potentials and graded
Neuron cell body
Te biosynthetic center of a neuron; also called the
perikaryon, or soma.
Functional groups of neurons that process and integrate
tīds) A class of neurotransmitters including
beta endorphins and enkephalins (which act as euphorics and reduce
perception of pain) and gut-brain peptides.
Chemical messenger released by neurons that may,
upon binding to receptors of neurons or eﬀector cells, stimulate or in-
hibit those neurons or eﬀector cells.
Consist of fatty acid chains and glycerol; also called triglyc-
erides or triacylglycerols. Commonly known as oils when liquid.
Displacement reaction in which mixing an acid
and a base forms water and a salt.
tron) Uncharged subatomic particle; found in the atomic
tro-ﬁl) Most abundant type of white blood cell.
ik) Acetylcholine-binding receptors of all
autonomic ganglionic neurons and skeletal muscle neuromuscular junc-
tions; named for activation by nicotine.
Nitric oxide (NO)
A gaseous chemical messenger; diverse functions
include participation in memory formation in the brain, and causing va-
sodilation throughout the body.
tor) Receptor sensitive to potentially damaging
stimuli that result in pain.
Failure of sister chromatids to separate during mitosis
or failure of homologous pairs to separate during meiosis; results in ab-
normal numbers of chromosomes in the resulting daughter cells.
ed) Axons lacking a myelin
sheath and therefore conducting impulses quite slowly.
Electrically balanced molecules.
Nonvolatile (ﬁxed) acid
Acid generated by cellular metabolism that
must be eliminated by the kidneys.
rin) A catecholamine neurotrans-
mitter and adrenal medullary hormone, associated with sympathetic
nervous system activation.
Te double membrane barrier of a cell nucleus.
ik) Class of organic molecules that includes DNA
o-li) Dense spherical bodies in the cell nucleus involved
with ribosomal RNA (rRNA) synthesis and ribosomal subunit assembly.
kle-o-sōm) Fundamental unit of chromatin; consists of
a strand of DNA wound around a cluster of eight histone proteins.