Ch 10 CWP Terms Practice Quiz
applies to neurons located in the central nervous system (CNS) that project their
axons outside the CNS and directly or indirectly control muscles. It is often
synonymous with efferent neuron.
Impulses leaving on a neuron of a neuronal pool often exhibit ___ by passing into
several other output fibers.
consisting of an absolute and relative phase. In the absolute phase, the Na+
channels cannot be opened by a stimulus; they have entered an inactivated state.
This is time-dependent, and during this phase no action potential, irrespective of
applied voltage, will be fired. In the relative phase (immediately after the absolute
phase), action potentials can be initiated, but the threshold is greater.
Neurons within the central nervous system that are organized into groups
non-neuronal cells that provide support and nutrition, maintain homeostasis, form
myelin, and participate in signal transmission in the nervous system. They
surround neurons and hold them in place, to supply nutrients and oxygen to
neurons, insulate one neuron from another, and destroy pathogens and remove
Several vertebrate axons are surrounded by a myelin sheath allowing rapid and
efficient saltatory propagation of action potentials. The contacts between neurons
and glial cells display a very high level of spatial and temporal organization in
myelinated fibers. The oligodendrocytes in the central nervous system (CNS) and
Schwann cells in the peripheral nervous system (PNS), are wrapped around the
axon, leaving the axolemma relatively uncovered at regularly spaced intervals at
the ___ .
a type of neuron with dendrite and axon emerging from same process. a single
neurite, round body and with different segments that serve as superficial receptors
or terminals. They are more common in the nervous system of the invertebrates, or
premature embryos. In adult humans, they are found always in dorsal root ganglia.
Enzyme catalyzing breakdown of several biogenic amines, such as serotonin,
adrenaline, noradrenaline, dopamine.
the interface where the membranes of the two cells flank each other across a
slender gap. The narrowness of the gap (20-40 nm) enables signaling molecules
known as neurotransmitters to pass rapidly from one cell to the other by diffusion.
A structure that recognizes a stimulus in the internal or external environment of an
organism. In response to stimuli it initiates sensory transduction by creating graded
potentials or action potentials in the same cell or in an adjacent one. It may be a
specialized portion of the plasma membrane, a whole cell associated with a neuron
ending, or a group of such cells.
A neurotransmitter that is not reabsorbed by the pre-synaptic neuron or broken
down into a metabolite. They end up spending a significant amount of time in the
CSF (cerebrospinal fluid) and influencing (or modulating) the overall activity level
of the brain. For this reason, a neurotransmitter may also considered as a ___.
Example of this category is serotonin.