ANS physiology Flashcards
autonomic vs somatic
autonomic: PNS, SNS, enteric
- skel muscle, glands, cardiac
- efferent and afferent pathways
- cell bodies outside the CNS in clusters (ganglia)
somatic: consious control of skeletal muscles
- cell bodies in the CNS (nuclei)
- axons can be outside the CNS
- afferent info reflex arch to spinal cord to activate efferent pathways to the muscle
- higher order processesing in the motor cortex of the brain
SNS stimulation
increase HR/BP
dilate bronchioles
shunt blood to skeletal muscles
- epi from adrenal glands
- norepinephrine directly release from CNS
has to be continuously stimulated
PNS stimulation
stimulating once to bring back to baseline
shunts blood to GI, urology, endocrine
visceral structures
PNS vs SNS neuron pathway names
SNS: thoracolumber (spinal cord)
PNS: craniosacral (brain and spinal cord)
cranial nerve #10 vagus most important (75% of PNS output)
thoracomber
SNS
- short preganglion (lightly myelinated)
- long postganglion (terminates on effector organ)
craniosacral
-long preganglion
- short post ganglion
ganglia location in PNS vs SNS
SNS: close to spinal cord
PNS: in visceral effector organs
Enteric NS
GI mainly under PSN
input mainly inhibitory
many neurons are non-adrenergic non-cholinergic
what do adrenergic neurons release
norepinephrine
what do cholinergic neurons release
ach
what do enteric neurons release
substance P
somatostatins
hormones released from the two neuron ANS
PNS and SNS preganglionic fibers release ACh
SNS: postganglionic fibers release norepinephrine or ACh
PNS: all post gang. release ACh
adrenergic receptors
Alpha 1:
