3. Physiology of ANS

Question 1

Where are autonomic responses processed?

Answer 1

hypothalamus

Question 2

In an autonomic reflex arc, the alpha-motor neuron (in skeletal muscle reflex arc) is replaced by ________.

Answer 2

autonomic nervous system

Question 3

Is the ANS a 1 -neuron or 2-neuron pathway?

Answer 3

2-neuron pathway

1. Pre-synaptic neuron: cell body (in CNS) terminates terminates in ganglion in periphery.
2. Cell body (in the ganglion) terminates on the end organ.

Question 4

In ANS, what neutrotransmitter is released by pre-ganglionic axon?

Answer 4

Acetylcholine

Question 5

What type of receptors do post-gangliong cells express at the post-synaptic membrane?

Answer 5

nicotinic cholinergic receptors

Question 6

Where do parasympathetics exit the CNS?

Answer 6

cranial and sacral

Question 7

Where do sympathetics exit the CNS?

Answer 7

thoracic and lumbar

Question 8

Where are parasympathetics located?

Answer 8

on/near target organ

Question 9

Where are sympathetics located?

Answer 9

sympathetic chain

Question 10

What do the yellow arrows indicate?

Answer 10

varicosities (boutons -or- en passant synapses)

Question 11

What type of muscles are shown in this slide?

Answer 11

smooth muscle

Question 12

Varicosities of the autonomics work the same as _____ of the NMJ.

Answer 12

pre-synaptic terminal

(Varicosities contain vesicles of NT, mitochondria, etc.)

Question 13

In general, what is the difference between the post-synaptic side of synapse #1 and #2?

Answer 13

Ligand-gated receptors are spread out on the post-synaptic terminal.

Question 14

What neurotransmitter is released from parasympathetic post-ganglionic (post-synaptic) axon?

Answer 14

Acetylcholine (binds to mAChr on target cells)

Question 15

Muscarinic receptors are part of what family of receptors?

Answer 15

metabotropic (serpentine)

Question 16

Which muscarinic receptor is involved in:

• in CNS - not autonomic - memory
• increase secretion of salivary glands
• increase secretion of acid secreting cells of stomach

Answer 16

M1R

Question 17

Which muscarinic receptor is involved in:

• SM cells (contraction)
• exocrine glands (secretion)

Answer 17

M3R

Question 18

Which muscarinic receptors are found in the CNS?

Answer 18

M1R & M5R

Question 19

Which muscarinic receptor is involved in:

• cardiac effects > slow HR

Answer 19

M2R

Question 20

Which muscarinic receptors signal through Gq?

Answer 20

M1R, M3R, M5R

Question 21

Which muscarinic receptors signal through Gi/o?

Answer 21

M2R and M4R

Question 22

effect of Gq/11

Answer 22

Gq/11 > inc intracellular Ca2+

[in SKM = contract, in SMG = secretion]

Question 23

effect of Gi/o

Answer 23

Gi/o > decrease in cAMP (M2R also directly interacts at K channels)

Question 24

What neurotransmitter is released from sympathetic post-ganglionic (post-synaptic) axon?

Answer 24

Norepinephrine (binds to an adrenergic receptor)

Question 25

Adrenergic receptors are part of what family of receptors?

Answer 25

metabotropic (serpentine)

Question 26

* SM blood vessels / urinary and reproductive tracts (*contraction*) * Liver (*glycogenolysis, glucogeonesis*) * Adipose tissue (*lipolysis*) * Lacrimal glands (*reduced watery secretion*) * Radial muscle of iris (*contraction of m = dilation of pupil*)

Answer 26

alpha-1 receptors

Question 27

signaling of alpha-1 adrenergic receptors

Answer 27

Gq/11 \> increased Ca2+ intracellularly

Question 28

* GI sphincters (*contraction*) * pancreas (*increase glucagon, decrease insulin*) * SM of blood vessels (*dilation*) * platelets (*increase clotting*)

Answer 28

alpha-2 receptors

Question 29

signaling of alpha-2 adrenergic receptors

Answer 29

Gi/o coupled \> decreased adenylate cyclase/cAMP

Question 30

* cardiac tissue * SA node = *increased HR* * Ventricular muscle = *increased of contraction* * salivary glands (*viscous secretion*) * adipose tissue (*lipolysis*)

Question 31

signaling of beta-1 adrenergic receptors

Answer 31

Gs-coupled \> increased adenylate cyclase activity and cAMP production

Question 32

* Relaxation of : * bronchiole SM * GI SM * urinary/reproductive SM * vascular SM * Liver (*glycogenolysis*) * Eye (*relaxation of ciliary muscle - flattens lens*)

Answer 32

beta-2 adrenergic receptors

Question 33

signaling of beta-2 adrenergic receptors

Answer 33

Gs-coupled \> increased adenylate cyclase activity & cAMP production

Question 34

* white adipose tissue (*lipolysis*) * brown adipose tissue (*heat production*)

Answer 34

beta-3 adrenergic receptors

Question 35

signaling of beta-3 adrenergic receptors

Answer 35

Gs-coupled \> increased adenylate cyclase activity & cAMP production

Question 36

What releases epinephrine during sympathetic response?

Answer 36

chromaffin cells of the adrenal medulla

Question 37

sympathetic system and adrena medulla

Answer 37

* some sympathetic axons go through ganglion and synapse in the adrenal medulla (rather synapsing in paravertebral ganglion) * pre-ganglion releases ACh, which bings to mAchR on chromaffin cells * epinephrine is released into the blood

Question 38

characterize the "rest and digest" parasympathetic response

Answer 38

* get O2 * slow HR * low BP * digest food * fuel from GI

Question 39

characterize the "fight or flight" parasympathetic response

Answer 39

* need O2 and get it to muscle * fast HR * no digestion * need fuel