neurologic system part 1 Flashcards
what does the PNS consist of?
cranial and spinal nerves
tell me about an afferent pathway
ascending; sensory to spinal column
tell me about an efferent pathway
descending; innervate effector organs
what does the somatic NS consist of and what does it control
motor and sensory pathways that regulate voluntary motor control of skeletal muscle
what does the autonomic NS consist of and what does it control
motor and sensory pathways that control the bodys internal environment through involuntary control of organ systems
what NS are the sympathetic and parasympathetic NS from
autonomic
how big are neurons
variable size and structure throughout the NS
what neurons continue to divide
olfactory
what are the cellular components of a neuron
microtubules, neurofibrils, and nissl substances
what do neurons do
receive, integrate, and transmit information to other cells throughout the body
what are the 3 main components of a neuron
dendrites, cell body, and axon
dendrites?
elongated processes that receive information from other neurons or the environment
where do axons conduct impulses
away from cell body
where is the cell body/soma located
mainly CNS
what are densely packed cell bodies in the CNS
nuclei
what are densely packed cell bodies in the PNS
ganglia
where do dendrites send impulses
cell body
axon hillock?
cone shaped, nissl free area where the axon leaves the cell body
axon initial segment?
area of axon with lowest threshold for stimulation so action potentials begin here
myelin?
segmented layer of lipid material that insulates the axon
what is myelin formed and maintained by
schwaan cells
endoneurium?
layer of CT around each axon
neurilemma?
thin membrane btwn myelin sheath and endoneurium
nodes of ranvier?
interruptions in the myelin sheath
