4-Autonomic Nervous System Flashcards
Generally describe the autonomic nervous system
aka visceromotor, involuntary, efferent only
How many cells are required for autonomic transmission
two (preganglionic and post ganglionic)
What parts of the autonomic system are myelinated
only pregangionic fibers
T/F Autonomic is only excitory
False, autonomic is both excitatory and inhibitory
Name effector organs of the ANS
cardiac muscle, glands, smooth muscle (although effector organs do not need ANS to function)
What is autonomic tone?
both the sympathetic and parasympathetic working together, working at same time to varying degrees
Where do the sympathetic originate?
T1-L2 and brainstem/S2-S4 respectively
What are the destinations of the sym/para respectively?
organs and body wall/ only body wall
Which sym/para has the longest preganglionic fibers
parasympathetic
Where are the cell bodies of the sympathetic located
lateral horn and the sympathetic chain ganglia
What neurotrasmitter do the presynaptic fibers use?
Ach
What neurotrasmitter do the postsynaptic fibers use
symp (NE or Ach) para (Ach only)
Describe the sympathetic chain
aka sympathetic trunk, runs the length of vertebral column, chain ganglia contain post ganglionic cell bodies
What are the two types of communicating rami
white (IN to the chain, myelinated preganglionic, T1-L2) and gray (OUT of the chain, unmyelinated postganglionic, at all spinal nerve)
Describe generally the parasympathetic system
aka craniosacral, brainstema dn lateral horn of S2-4, go to organs only, possess terminal ganglia near the near or part of the termal organ
Name cranial nerves involved in the para
3, 7, 9 and 10 (vagus)
What does the vagus nerve innervate
thoracic organs as well as the foregut and part of hind gut
Trace the sym pathway from nerve cell bodies to target tissue in body wall
lateral horn, white communicating rami, chain ganglia, gray rami, and dorsal/vental nerve
How do sympathetic pathways reach the head or lower limbs
enter the white rami at initial spinal level then travel higher or lower on the chain and exit a gray rami to form nerve
Describe the pathway of symp thoracic organs
ventral horn, ventral rami, white rami to chain and straight to cervical splanchnic nerve (3) to heart and lungs
Describe the symp pathway to the abdominal organs
ventral horn, white ramus, through chain, cell body in collateral ganglion as part of the thoracic splanchnic nerve (3), stomach+
Which pathway of the sym has only one neuron
innervation of the adrenal medulla
Name the terminal nerve that include a collateral ganglia
thoracic splanchnic and lumbar/sacral splanchnic
Where are collateral ganglia located
on the aorta
Describe the path of the vagus nerve
made of preganglionic, L/R descend thru neck and bsend branches to cardiopulmonary plexus, break up to form the esophageal plexus before coalescing to cross the diapragm where they innervate foregut and midgut
Where anterior/ posterior do the L/R vagus end up
L- anterior to vagal trunk, R- posterior vagal trunk
Describe the pelvic splanchnic
parasympathetic that leave S2-4 via the ventral rami and innervate the hindgut and pelvic organs (digestion, urnation (etc) and sexual arousal)
Describe the path of para pathway to pelvic organ
lateral horn, ventral root to ventral ramus, pelvic splachnic nerve to terminal ganglion on organ
What are visceral afferents?
sensory nerves from the organs-stretch, baro and chemo receptor, not part of ANS, rarely reaches conscious levels
Describe the path of visceral afferent pathways
back track with autonomic pathway until spinal nerve then exit to ventral horn and synapse on dorsal horn, with cell bodies in the DRG
Why is referred pain an issue with viscerosensory?
there is cross-talk with somatic sensory because they both go to the dorsal horn
What are visceral reflex
visceral sensation results in visceral/somatic effects ie. Blood pressure or cough reflex
