Autonomic Nervous System 1

Question 1

divisions of the autonomic nervous system

Answer 1

sympathetic and parasympathetic nervous system

Question 2

sympathetic nervous system (SNS)

Answer 2

thoracocolumbar division, mediates stress responses involved in “fight or flight”

Question 3

parasympathetic nervous system (PNS)

Answer 3

craniosacral division, mediates vegetative responses involved in resting and digesting

Question 4

SNS activation of the heart

Answer 4

stimulation of heart rate at SA node (positive chronotropic effect), stimulation of AV nodal conduction (positive dromotropic effect), stimulation of myocardial contractility (positive inotropic effect)

Question 5

PNS activation of the heart

Answer 5

inhibition of heart rate at SA node (negative chronotropic effect), inhibition of AV nodal conduction (negative dromotropic effect), inhibition of atrial contractility (negative inotropic effect)

Question 6

muscarine

Answer 6

exogenous agonist (activator) of muscarinic cholinergic receptors

Question 7

atropine

Answer 7

exogenous antagonist (inhibitor) of muscarinic cholinergic receptors

Question 8

sympathetic preganglionic fibers are typically _____; postganglionic fibers are typically _____

Answer 8

short; long

Question 9

parasympathetic preganglionic fibers are typically _____; postganglionic fibers are typically _____

Answer 9

long; short and lie within or very close to their target tissues

Question 10

divergence

Answer 10

enables the SNS to generate widespread responses of numerous effectors when physiologically necessary.

average preganglionic axon in the SNS contacts 100 postganglionic neurons by collateral branching (in comparison to PNS which synapses with 15-20)

Question 11

“en passant” synapses (varicosities)

Answer 11

characteristic of the ANS and permit a single axon to have broad actions in target tissues.

Question 12

SNS target tissues

Answer 12

express distinct adrenergic receptor subtypes with different affinities for epi and norepi, sometimes use muscarinic cholinergic receptors (eccrine sweat glands), are broadly activated by epi/norepi from the adrenal medulla

Question 13

PNS target tissues

Answer 13

express various combinations of 5 muscarinic cholinergic receptors (M1-M5)

Question 14

epinephrine

Answer 14

greater affinity for beta adrenergic receptors. effects more prominent in heart, lungs, liver

Question 15

norepinephrine

Answer 15

greater affinity for alpha adrenergic receptors, effects more prominent in vasculature

Question 16

adrenal medulla

Answer 16

releases epinephrine and norepinephrine into the bloodstream during activation of the SNS.

Question 17

pheochromocytoma

Answer 17

tumor of the adrenal medulla results in headache, sweating, flushing, high blood pressure, anxiety, nausea, palpitations/chest pains, weakness, epigastric pain, tremor

Question 18

horner sysndrom

Answer 18

ptosis (drooping eyelid), anhidrosis (dryness of face/no sweat), miosis (partial constriction of pupil)`

Question 19

alpha 1 receptors

Answer 19

located on the vascular smooth muscle of the skin and splanchnic regions, GI and bladder sphincters, radial muscle of the iris

mechanism: Gq protein, stimulation of phospholipase C, increase in IP3 and intracellular Ca

Question 20

beta 1 receptors

Answer 20

located in SA node, AV node, and ventricular muscle of the heart

mechanism: Gs protein, stimulation of adenylate cyclase and increase in cAMP

Question 21

beta 2 receptors

Answer 21

located on vascular smooth muscle of skeletal muscle, bronchial smooth muscle, and in the walls of the GI tract and bladder

mechanism: Gs protein, stimulation of adenylate cyclase and increase in cAMP