Neurophysiology

Question 1

alpha1 receptors

adrenergic

Answer 1

location = SmM of skin and splanchnic regions, GI, bladder sphincteres, and radial muscles of iris

produces excitation = contraction or constriction

NE and Epi (think NE)

Mechanism:
Gq protein –> phospholipase C –> (+) IP3 and Ca2+

Question 2

alpha 2 receptors

adrenergic

Answer 2

location = presynaptic nerve terminal of walls of GI tract

produces inhibition = relaxation and dilation

NE and Epi

Mechanism:
Gi protein –> (-) adenylate cyclase –> (-) cAMP

Question 3

beta 1 receptors

adrenergic

Answer 3

SA node, AV node, and ventricular heart muscle

produce excitation = increased heart rate, increased conduction velocity, and increased contractility

(+) = both NE and Epi (more sensitive than alpha1 receptors!!)

(-) = propanolol

Mechanism:
Gs protein –> stimulation of adenylate cyclase –> cAMP

Question 4

beta 2 receptors

adrenergic

Answer 4

SmM of bronchials, and walls of GI and bladder

produces relaxation

more sensitive to Epi thanNE

more sensitive to Epi than alpha1 receptors

(-) propanolol

Mecanism (same as beta1):
Gs protein –> stimulation of adenylate cyclase –> cAMP

Question 5

Parasympathetic signal pathway

Answer 5

CNS –> long preganglionic –> release ACh

ACh stimulates nicotinic receptor –> postganglionic neuron (+)

release ACh to effective organ –> (+) muscarinic receptor

Question 6

Sympathetic signal pathway

Answer 6

CNS –> short preganglionic –> release ACh

ACh stimulates nicotinic receptor –> postganglionci neuron (+)

release NE (mostly) –> (+) alpha1,2 or beta1,2

Question 7

adrenal stimulation signal pathway

Answer 7

preganglionic neuron release ACh

ACh stimulates nicotinic receptor on adrenal galdn –> (+) mostly epi than NE

Question 8

Pacinian corpuscle

Answer 8

onion like sructures in the subcutaneous skin (surrounding unmyelinated nerve endings)

vibration, tapping

rapidly adapting

Question 9

Meissner’s corpuscle

Answer 9

present in non hairy skin

velocity sensation encoded

rapidly adapting

Question 10

Merkel’s disk

Answer 10

transducer in on epithelial cells

location sensation encoded

slowly adapting

Question 11

which autonomic receptor is blocked by hexamethonium at the ganglia….but not at the neuromuscular junction

Answer 11

cholinergic nicotinic receptors

Question 12

Prazosin (medication to lower high bp)

mechanism =?

Answer 12

inhibition of alpha-1 receptors on vascular SmM

prevents constriction

Question 13

which is mediated by parasympathetic stimulation?

dilation of bronchiolar SmM

erection

ejaculation

constriction of GI sphincters

increased cardiac contractility

Answer 13

erection

Question 14

which autonomic receptor mediates increased heart rate

Answer 14

adrenergic beta 1

Question 15

what drugs would you give to an asthma patient

Answer 15

beta2 agonists

• albuterol
• epinephrine (to lesser extent NE)

Question 16

what drugs would you NOT give an asthma

Answer 16

beta2 antagonists

- propanaolol

Question 17

which autonomic receptors stimulate adenylate cyclase

Answer 17

beta 1 and 2

Question 18

NE = what kind of agonist

Answer 18

beta 1

Question 19

atropine = what kind of antagonist

Answer 19

muscarinic cholinergic antagonist

Question 20

clonidine

Answer 20

alpha 2 agonist

Question 21

curare

Answer 21

nicotinic cholinergic antagonist

Question 22

propanolol

Answer 22

beta 1 and 2 antagonist

Question 23

receptor that mediates release of epinephrine from adrenal medulla

Answer 23

ACh nicotinic

Question 24

which autonomic receptor is stimulated by low levels of epinephrine released from adrenal medulla

Answer 24

beta 2 receptors

more sensitive than alpha 1

Question 25

autonomic recpetor that (+) IP3/Ca2+

Answer 25

alpha 1

Question 26

autonomic receptor that (-) adenylate cyclase

Answer 26

alpha 2