ANS part 2 Flashcards
(25 cards)
what is the origin of the PNS?
craniosacral
What does the PNS target?
smooth muscle, cardiac muscle, and glands
What are the effects of stimulation of the PNS?
Salivation Lacrimation Stimulate digestion Urination Defecation Pupillary constriction Vasomotor control Bronchial control
What is the main nerve of the PNS?
Vagus (wandering - because innervates a lot of things - thoracic and abdominal structures)
What is the origin of the vagus nerve?
brainstem
True or False. The vagus nerve innervates all nerves of the larynx.
FALSE. The vagus nerve innervates all nerves of the larynx EXCEPT cricothyroid (superior laryngeal nerve)
If both nerves paralyzed, what might we see in regards to the vocal cords?
stridor/laryngeal obstruction
What are the two types of cholinergic receptors?
nicotinic and muscarinic
True or False. ACh can be found at the presynaptic nerves in both SNS and PNS.
TRUE. PNS has ACh at both pre and postsynaptic nerves while SNS only has ACh at presynaptic nerves.
What happens if we block acetylcholinesterase?
Huge parasympathetic outflow (give anticholinergics to block/counteract)
What are the steps causing release of ACh from the vesicles?
depolarization of nerve-> influx of Ca2+ ->vesicular exocytosis -> NT release in synapse
What effect does Botulism Toxin A have on the PNS?
binds to vesicles and prevents exocytosis (causes paralysis and PNS derangements)
How is termination of ACh carried out?
- reuptake of active ACh
- hydrolysis via acetylcholinesterase to acetate and choline
- diffusion away from synapse (minimal)
How does reuptake of ACh occur?
by high affinity NaCl co-transport coupled to Na/K ATPase
What are some of the acetylcholinesterase inhibitors (anticholinesterase)?
neostigmine, endrophonium, pyridostigmine, physostigmine
Where are nicotinic receptors located?
NMJ, autonomic ganglia (pre synaptic SNS and PNS)
Where does ACh bind on the nicotinic receptor?
the alpha subunit
What is the function of the M1 receptor?
autonomic ganglia and CNS
What is the function of the M2 receptor?
supraventricular cardiac (bradycardia and decr contractility)
What is the function of the M3 receptor?
smooth muscle and glands
What are the steps to activation of the PNS via nicotinic receptors?
stimulation -> increased Na/K permeability -> depolarization
What are the steps to activation of the PNS via muscarinic receptors?
stimulate G-protein -> activate phospholipase C -> breakdown fatty acids into IP3 and DAG -> increased Ca 2+ released from sarcoplasmic reticulum
True or False. ACh binding always leads to smooth muscle constraction due to increased Ca2+
FALSE. ACh increases nitric oxide (NO) release from endothelial cells. NO is a potent vasodilator.
What is a cholinergic crisis?
uncontrolled upregulation of PNS
causes mydriasis, miosis, perspiration, salivation, bronchoconstriction, bronchial secretions, flaccid paralysis, respiratory failure
**SLUDGE BB
