Unit 2 - PNS: Efferent Division

Question 1

sympathetic nerve fibers originate:

Answer 1

thoracic & lumbar areas of CNS

Question 2

characteristics of sympathetic nerve fibers:

Answer 2

1. preganglionic fibers are SHORT
2. postganglionic fibers are LONG
   3 Terminal ganglia lie closer to the spinal cord

Question 3

parasympathetic nerve fibers originate:

Answer 3

cranial & sacral areas of CNS

Question 4

characteristics of parasympathetic nerve fibers:

Answer 4

1. preganglionic fibers are LONG
2. postganglionic fibers are SHORT
3. terminal ganglia lie close to the effector organ

Question 5

Preganglionic fibers of BOTH parasympathetic & sympathetic release:

Answer 5

acetylcholine (ACh)

Question 6

POSTganglionic fibers of sympathetic system release:

Answer 6

norepinephrine (aka adrenaline or noradrenaline)

Question 7

POSTganglionic fibers of parasympathetic system release:

Answer 7

acetylcholine (ACh)

Question 8

cholinergic fibers release ________

Answer 8

acetylcholine (ACh)

Question 9

Adrenergic fibers release ______

Answer 9

norepinephrine (adrenaline)

Question 10

Cholinergic receptors

Answer 10

1. nicotinic (activated by tobacco plant derivative nicotine)
2. muscarinic (activated by mushroom poison muscarine)

Question 11

where are Nicotinic receptors found?

Answer 11

all postganglionic cell bodies in autonomic system

Question 12

Where are Muscarinic receptors found?

Answer 12

on effector cell membranes innervated by parasympathetic postganglionic neurons

Question 13

Adrenergic

Answer 13

1. alpha ( a1 & a2)

2. beta (b1 & b2)

Question 14

a1 and b1 will lead to what type of response?

Answer 14

excitatory

Question 15

a2 and b2 will lead to what type of repines?

Answer 15

inhibitory

Question 16

a1:

1. where located?
2. NT affinity?

Answer 16

1. located in most sympathetic target tissues
2. greater affinity (more sensitive) to Norepinephrine
3. activates the IP3 - Ca2+ second messenger system

Question 17

a2:

1. where located?
2. NT affinity?

Answer 17

1. located mainly on digestive organs
2. greater affinity (more sensitive) to Norepinephrine
3. Inhibits cAMP production in target cell

Question 18

b1:

1. where located?
2. NT affinity?

Answer 18

1. only in the heart
2. equal affinities for Norepinephrine and Epinephrine
3. activates the cAMP second-messenger pathway

Question 19

b2:

1. where located?
2. NT affinity?

Answer 19

1. found on smooth muscles of arterioles & bronchioles
2. bind only with epinephrine
3. activates the cAMP second-messenger pathway