CHAPTER 12
The slowest category of nerve fibers are the?
C fibers, and they conduct impulses at 1 meter per second.
The connective tissue wrapping that surrounds bundles (fascicles) of axon is the
Perineurium
Chemically gated ion channels are mainly found in the ______________ segment of a neuron?
Receptive
The glial cell that protects neuron cell bodies located within angle is the?
Satellite
A mixed nerve is one that contains both?
Sensory and motor neurons
In a mixed nerve
Some axons transmit sensory information and others transmit motor information
As an axon approaches the cell onto which it will terminate, it generally branches repeatedly into several
Telodendria
When transmission occurs at a synapse, neurotransmitter is released by?
The presynaptic neuron's synaptic knob in the synaptic cleft
What do all glial cells have in common?
They assist neurons in their respective functions
The type of voltage-gated channel that possesses an inactiviation gate that temporarily closes after the channel is active is the
Voltage-gated sodium channel
Which occurs first
absolute refractory period
The endoneurium is composed of
areolar connective tissue
The glial cell with the responsibility of occupying the space left by dead or dying neurons is the
astrocyte
With damage to nerve fibers, larger distances between the site of damage and the target structure innervated result in
decreased
According to Ohm's law current is
directly related to voltage and inversely related to resistance
In neurophysiology, the term "summation" refers to the addition of
postsynaptic potentials at the initial segment.
Following damage to axons nearby, oligondendrocytes
secrete growth-inhibitory molecules
The afferent division of the nervous system is also known as the _____________ division
sensory
Which function is not a function of the motor division of the nervous system
transmits impulses from the viscera
Continuous conduction of a nerve impulse occurs only along
unmylinated axons
Somatic motor neuron axons fall into the category of
A fibers
When a nerve impulse reaches the transmissive segment of a neuron?
Calcium diffuses into the neuron and neurotransmitter is released by exocytosis.
The type of neuronal circuit that ensures that we continue to breathe while asleep is _________________ circuit?
Converging
Which choice correctly orders the connective tire wrappings of a nerve, beginning at the outermost layer?
Endineurium-perineurium-epineurium
The Glial cell that myelinates and insulates axon in the peripheral nervous system is the?
Ependymal cell
Neural stem cells in the CNS
Have no known function.
Which is not characteristic of neurons?
High mitotic rate
Which statement is consistent with the current understanding of the neural tissue
Most neurons formed in fetal development last a lifetime, but some brain regions in adults can generate new neurons
Based on structure, the most common type of neuron is the ________________ neuron
Multipolar
Which functional class of neurons lies entirely within the cns?
interneurons