Autonomic physiology Flashcards
Which branch of the nervous system is voluntary and how does it send its signal?
Somatic , and it is one axon orginating in the CNS and directly into the muscle
How are the parasympathetic axons different from the sympathetic axons?
Parasympathetic axons have a long preganglionic axon and a short postganglionic axon, while the sympathetic axons have a short preganglionic and long postganglionic
What does the parasympathetic ganglionic axons release?
The parasympathetic releases ACh at both the pre and post synaptic junctions
What does the sympathetic ganglionic axons release?
They release ACh at the presynaptic junction and either ACh or NE/E at the post ganglionic junctions to either muscarinic or Alpha/beta anergic
How is the actions of the parasympathetic nervous system terminated?
Acetylcholinesterase
What are all autonomic receptors coupled to?
GTP binding proteins including Gq (PI turnover), Gs (increase cAMP), and Gi (decrease cAMP, increased K+ conductance)
Where does the PNS originate from in the spinal cord?
Cranial/Sacral
Where does the SNS originate from in the spinal cord?
Thoracic, upper lumbar
How are actions terminated in the SNS?
Reuptake, degradative enzymes
How is acteylecholine synethesized?
From choline and acetate via action of choline acetyletransferase
What do ACE inhibitors target?
Acetyletransferase to stop the increase of ACh
What is the process of norepinephrine synthesis?
Tyrosine –> DOPA –> Dopamine (stored)–>Norepinephrine
How is NE action terminated?
Degradative enzymes MAO and Catechol-O-methytransferase
How does the autonomic innervation affect the lungs?
SNS –> Dilation of the bronchioles
PNS–> Constrict bronchioles
How does the autonomic innervation affect the heart?
SNS –> Beta-1 receptors stimuates the heart at SA node, increase AV nodal conduction, and force of contraction
PNS –> M2 receptors, decreases AV nodal conduction, no parasympathetic innervation of the ventricle, but exogenous ACh will decrease force of contraction
How does the autonomic innervation affect the vasculature?
SNS –> Alpha-1 - vasoconstriction, Beta2 vasodilation *via EPI)
There is no ONS innervation of vasculature but exogenous muscarinic drugs will cause vasodilation (NO)
How does the autonomic innervation affect the baroreceptors?
Reflex phenomena - decrease in BP sensed by baroreceptors will lead to an increase in heart rate and increase in BP will lead to decrease in HR
How does the autonomic innervation affect the eyes?
SNS –> alpha 1, dilator
PNS–> M3 receptors, constrictor (light)
How does the autonomic innervation affect the ciliary muscle?
SNS–> Beta2, causes relaxation for far view
PNS–> M3, contraction for near vision
How does the autonomic innervation affect the liver?
SNS will lead to an increase in glucose
What all entails the fight or flight response?
rlease of epi leads to coordinated response, epi causes vasoconstriction of visceral beds and vasodilation of the vessels in skeletal muscel, bronchiols to dilate, GI tract and bladder to relax, eyes to dilate, skin to sweat, glycogenolysis in the liver
