the number of inputs to a single neuron reflects the degree of convergence
what does the term divergence mean?
the number of targets innervated by any one neuron represents its divergance,
T or F and if false give the right answer. The synaptic cleft is the location of a number of polysaccharides that assist with the transmission of a signal from one cell to another.
F, enzymes that influecne the diffusion, biding, and degradation of the molecues secreted by the presynaptic terminal are found in the synaptic cleft.
In what organelle are neurotransmitters found before they are released in the synaptic cleft?
where are astrocytes located?
in the central nervous system
what is the function of astrocytes?
one of the functions of the astrocyte is to maintain the appropriate chemical environment for neurons. Some astrocytes can also act as stem cells to produce neurons or other glia.
where are oligodendrocytes found?
in the central nerv. system
where are schwann cells found?
in the peripheral nerv system.
what is the function of oligodendrocytes/schwann cells
to mylenate some axons.
what are the two types of stem cells in the nerv system?
SVZ astrocytes and oligodendroglial cells
What is the function of microglial cells?
they remove cellular debris from sites of injury or normal cell turnover. They also secrete cytokines that regulate inflammation and control cell survival/death.
what is the diff. between efferent and afferent neurons
afferent neurons carry information to the brain and efferent neurons carry info from the brain
T or F. During the myotatic reflex, when the sensory receptors in the quadricep are stimulated, the motor neurons that are later stimulated only facilitate the contraction of the quadricep
False, the motor neurons that are later stimulated activate the quadricep and inhibit the hamstring
What is the role of the interneuron in the myotatic reflex?
some of the muscle sensory receptors of the quadricep synapse with interneurons in the spinal cord, which inhibits motor neurons that activate the hamstring muscles.
The human nervous system is divided into what three groups?
sensory systems (acquire info from the environment), motor systems (respond to sensory info by generating movements and other behavior, and associational systems (they mediate between the motor systems and the sensory systems)
The motor portion of the peripheral nerv system consists of what two parts?
the somatic motor division (connects brain and spinal cord to skeletal muscles) and the visceral/autonomic motor division (which innervates smooth muscles, cardiac muscles, and glands)
what are ganglia?
local accumulations of nerve cell bodies and suporting cells
what is the difference between a ganglion and a nucleus?
a ganglion is a cluster of neuron cell bodies in the PNS. a nucleus is a cluster of cell bodies within the CNS