UNit 6 The Autonomic nervous system Flashcards
What are the components of the peripheral nervous system?
12 pairs of cranical nervees, 31 pairs of spinal nerves, the autonomic nervous sysrwm
What are the four major types of fibers found in cranial and spinal nerves?
somatic afferent, somatic efferent, visceral afferent, visceral efferent
Where do nerve impulses from somatic afferents come from?
skin, joints, muscles
Where are the cell bodies for somatic afferents located?
posterior/dorsal root ganglia, crannial nerve ganglia
What is the pathway from a sensory receptor into the spinal cord?
one sensory neuron with body in dorsal root
Where is the first cell body found in the viceral efferent system?
intermediate zone of grey matter
Where is the second cell body (post ganglionic) neuron found for the visceral efferents?
outside the CNS in an autonomic ganglion
What are some commonly innervated structures with visceral efferents?
glands, cardiac muscle, smooth muscle
What is the primary goal of the autonomic nervous system?
maintain homeostasis
Why are autonomic fibers found all over the body?
they innervate blood vessels that have smooth muscle in their walls, also cardiac muscle, and glands (most parts of the body contain glands of some sort)
What are the two divisions of the autonomic nervous system?
sympathetic and parasympathetic
Where is the first cell body located in the sympathetic nervous system?
intermediolateral nucleus of lateral grey horn
Where do the axons of the sympathetic preganglionic neuron travel to?
leave the nervous system through the anterior or ventral root, enters the spinal nerve through ventral ramus, leaves ventral ramus to travel to the white communicating ramus where it connects to the sympathetic trunk
Where is the only place you find the preganglionic axons of the sympathetic nervous system?
white communicating rami
Where is the postganglionic neuron of the sympathetic nervous system found?
sympathetic trunk
Where is the sympathetic trunk located?
21-23 cell bodies located bilaterally along the vertebral bodies, they are linked together by other nerve fibers
Where does the sympathetic trunk extend from?
base of skull to coccyx
What is it called where the two sympathetic trunks join one another?
ganglion impar
Where might the axons of the preganglionic neurons synapse upon after entering the sympathetic trunk?
on a postganglionic sympathetic neuron at the same level as they entered, ascend to a higher level ganglion (true usually in thoracic region), descend to a lower neuron (true usually lumbar region), or they may pass through the trunk into a splanchnic nerve to synapse on a collateral ganglion located in the abdominal region
What are the collateral ganglion typically associated with?
large vessels of the abdominal aorta
Where are the postganglion axon fibers typically located?
exit sympathetic trunk via the gray comminicating rami to the anterior ventral ramus of the spinal nerve
where do the sympathetic post ganglionic fibers travel after they reach the spinal nerve?
distributed through the body to structures in the skin such as sweat glands, smooth muscles in blood vessels, erector pili muscles of limbs and body wall
What is the consequence of all parts of the body having blood vessels and glands?
all spinal nerves must receive a gray ramus with sympathetic nerve fibers
What is another possible course for the post ganglionic nerve fibers?
can leave the sympathetic trunk as viceral branches that travel directly to their effector organ
