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

Question 1

what are the branches of the nervous system?

Answer 1

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

Question 2

where do somatic afferents come from?

Answer 2

skin, muscle, joints

Question 3

where do visceral afferents come from?

Answer 3

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

Question 4

what are nociceptors?

Answer 4

respond to chemicals, also called chemoreceptors, respond to affectors

Question 5

what are mechanoreceptors?

Answer 5

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

Question 6

what are proprioceptros?

Answer 6

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

Question 7

tetrodotoxin

Answer 7

decreases contraction by inhibiting sodium channels

Question 8

omega-conotoxin

Answer 8

decreases contraction by inhibiting calcium channels

Question 9

botulinum toxin

Answer 9

decreases contraction by inhibiting ACh release

Question 10

physostigmine

Answer 10

increases contraction by inhibiting acetylcholinesterase

Question 11

alpha-tubocurarine

Answer 11

decreases contraction by inhibiting AChR channel

Question 12

efferent autonomic nerves typically originate from…

Answer 12

the medulla

Question 13

what important centers are located in the medulla?

Answer 13

cardiovascular and respiratory centers

Question 14

what happens to the HR during inspiration?

Answer 14

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

Question 15

what happens to the HR during expiration?

Answer 15

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

Question 16

what do sympathetic preganglionic neurons stimulate?

Answer 16

adrenal medulla to release Epi into the blood stream

Question 17

somatic nervous system to target organ

Answer 17

CNS to N1 nicotinic Ach receptor; in skeletal muscle

Question 18

parasympathetic NS to target organ

Answer 18

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

Question 19

sympathetic NS to target organ (non-adrenal)

Answer 19

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

Question 20

agonists, antagonists, NT for nicotinic receptors

Answer 20

nicotine; curare; ACh

Question 21

agonists, antagonists, NT for muscarinic receptors

Answer 21

muscarine; atropine; ACh

Question 22

curare is more selective for..

Answer 22

N1/Nm

Question 23

N1 is… N2 is…

Answer 23

muscle or Nm; postganglionic neurons or Nn

Question 24

where are muscarinic receptors?

Answer 24

parasympathetic actions so in target organs

Question 25

what does alpha 1 have a higher affinity for?

Answer 25

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)

Question 26

what does alpha 2 have a higher affinity for?

Answer 26

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

Question 27

what does beta 1 have a higher affinity for?

Answer 27

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

Question 28

what does beta 2 have a higher affinity for?

Answer 28

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

Question 29

how does the heart receive innervation to the nodes?

Answer 29

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

Question 30

what does hypercholinergic result in/mean?

Answer 30

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

Question 31

what does anticholinergic mean/result in?

Answer 31

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)

Question 32

what is autonomic tone? what are exceptions?

Answer 32

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

Question 33

what is denervation? what structure does it concern?

Answer 33

lose tone but tissue can compensate; adrenal medulla

Question 34

what is the baroreceptor reflex?

Answer 34

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

Question 35

what is the coronary chemoreflex?

Answer 35

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

Question 36

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

Answer 36

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

Question 37

what are the ways to therapeutically manipulate the ANS?

Answer 37

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

Question 38

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

Answer 38

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

Question 39

what are the antagonists of the Epi/NE system?

Answer 39

propanolol (beta)

Question 40

what are the agonists of the ACh system?

Answer 40

pilocarpine (Ach R muscarinic)

Question 41

what are the antagonists of the ACh system?

Answer 41

atropine (AChR muscarinic R) | glycopyrrolate (AChR muscarinic R)

Question 42

how does Reserpine work?

Answer 42

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

Question 43

what is vasovagal syncope?

Answer 43

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