HSF 2 - Unit 2 Physiology: Peripheral Nerves and the Autonomic Nervous System Flashcards

1
Q

what are the branches of the nervous system?

A

CNS - afferent and efferent
Afferent - receives info from somatic and visceral
Efferent: motor neurons and away from the CNS; branches to somatic and autonomic
somatic: innervates skeletal muscle
autonomic: involuntary and innervates smooth muscle, cardiac muscle, GI, etc., branches into sympathetic and parasympathetic
Sympathetic: fight or flight
Parasympathetic: rest and digest/feed and breed

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2
Q

where do somatic afferents come from?

A

skin, muscle, joints

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3
Q

where do visceral afferents come from?

A

organs, can travel through the spinal cord or vagus to the medulla

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4
Q

what are nociceptors?

A

respond to chemicals, also called chemoreceptors, respond to affectors

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5
Q

what are mechanoreceptors?

A

stretch receptors; pressure and stretch sensed, important in the lung and changes the conformation of the ion channel to depolarize nerves

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6
Q

what are proprioceptros?

A

sense changes in muscle or tendon length and tension; why we have the patellar tendon reflex; modified stretch receptor, both in the muscle spindle in the belly and in the tendons and is a protective measure to contract so you don’t overstretch

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7
Q

tetrodotoxin

A

decreases contraction by inhibiting sodium channels

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8
Q

omega-conotoxin

A

decreases contraction by inhibiting calcium channels

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9
Q

botulinum toxin

A

decreases contraction by inhibiting ACh release

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10
Q

physostigmine

A

increases contraction by inhibiting acetylcholinesterase

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11
Q

alpha-tubocurarine

A

decreases contraction by inhibiting AChR channel

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12
Q

efferent autonomic nerves typically originate from…

A

the medulla

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13
Q

what important centers are located in the medulla?

A

cardiovascular and respiratory centers

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14
Q

what happens to the HR during inspiration?

A

increases, decrease in parasympathetic output from ANS, increases cardiac pacemaker

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15
Q

what happens to the HR during expiration?

A

decreases, increase in parasympathetic output from the ANS via vagus n., slows cardiac pacemaker

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16
Q

what do sympathetic preganglionic neurons stimulate?

A

adrenal medulla to release Epi into the blood stream

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17
Q

somatic nervous system to target organ

A

CNS to N1 nicotinic Ach receptor; in skeletal muscle

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18
Q

parasympathetic NS to target organ

A

CNS through preganglionic fiber to ganglion that has N2 ACh receptor, then through postganglionic to target through M receptor with ACh again

19
Q

sympathetic NS to target organ (non-adrenal)

A

CNS through preganglionic fiber to N2 receptor and ACh in ganglion, then through postganglionic fiber to alpha and beta adrenergic receptors with NE, for smooth muscle, cardiac muscle, glands

20
Q

agonists, antagonists, NT for nicotinic receptors

A

nicotine; curare; ACh

21
Q

agonists, antagonists, NT for muscarinic receptors

A

muscarine; atropine; ACh

22
Q

curare is more selective for..

A

N1/Nm

23
Q

N1 is… N2 is…

A

muscle or Nm; postganglionic neurons or Nn

24
Q

where are muscarinic receptors?

A

parasympathetic actions so in target organs

25
Q

what does alpha 1 have a higher affinity for?

A

NE over Epi (ex: vasoconstriction, raise BP to get more flow overall and the A1 receptors constrict blood vessels in the gut to get more blood to periphery through shunts)

26
Q

what does alpha 2 have a higher affinity for?

A

Epi over NE (ex: presynaptic neuron); inhibitory G protein since the gamma subunit closes the VGCC so cannot release more NE = negative feedback to prevent too much release

27
Q

what does beta 1 have a higher affinity for?

A

Epi over NE (ex: increasing HR and cardiac contractility through Gs protein)

28
Q

what does beta 2 have a higher affinity for?

A

Epi significantly over NE (ex: bronchodilation, some vasodilation)

29
Q

how does the heart receive innervation to the nodes?

A

vagal nerve postganglionic releases ACh on the nodes, muscarinic receptors decrease HR

30
Q

what does hypercholinergic result in/mean?

A
muscarinic receptor overactivation; 
Diarrhea
Urination
Miosis (pupil constriction)
Bradycardia
Emesis
Lacrimation
Salivation
Sweating 
and the killer B's (bradycardia and bronchospasm)
31
Q

what does anticholinergic mean/result in?

A

anti-muscarinic
blind as a bat: dilated pupils
dry as a bone: dry mouth, eyes, decreased sweat
hot as hades: increased body temp
full as a flask: no urination
mad as a hatter: confusion (CNS)
the bowel loses tone and the heart runs alone (tachycardia)

32
Q

what is autonomic tone? what are exceptions?

A

neural stimulation to both sympathetic and parasympathetic to most organs (balance); blood vessels (more sympathetic), gut (more parasympathetic), sweat glands (sympathetic)

33
Q

what is denervation? what structure does it concern?

A

lose tone but tissue can compensate; adrenal medulla

34
Q

what is the baroreceptor reflex?

A

when BP is high, reduces HR and BP (by increasing vagal efferents and decreasing sympathetics), when it’s low it does the opposite

35
Q

what is the coronary chemoreflex?

A

parasympathetic reflex of the autonomic nervous system to lower HR during heart damage and preserve tissue; inflammatory mediators, Thromboxane A2

36
Q

what happens with stimulation of cardiac vagal afferents by inflammatory substances?

A

led to activation of cardiac vagal efferent nerves to slow HR and lower BP

37
Q

what are the ways to therapeutically manipulate the ANS?

A

receptor agonists/antagonists, block breakdown of NT, packaging of NT

38
Q

what are the agonists of the Epi/NE system? what doe they do?

A

Epi (alpha and beta, more beta than alpha)
NE (alpha and beta, more alpha than beta)
phenylephrine (alpha 1)
albuterol (beta 2)

39
Q

what are the antagonists of the Epi/NE system?

A

propanolol (beta)

40
Q

what are the agonists of the ACh system?

A

pilocarpine (Ach R muscarinic)

41
Q

what are the antagonists of the ACh system?

A

atropine (AChR muscarinic R)

glycopyrrolate (AChR muscarinic R)

42
Q

how does Reserpine work?

A

prevents packaging of NTs by inhibiting VMAT (vesicular monoamine transporter), cannot be packaged so no way to release and get broken down instead

43
Q

what is vasovagal syncope?

A

when the nucleus of the solitary tract is activated by brain regions like the amygdala, triggers are pain, emotional reaction, visual stimuli and you get a massive parasympathetic response but vasodilate and also turn off sympathetic response