Quiz 3 Flashcards

1
Q

What are the characteristics of somatic motor neurons?

A

-Controls only skeletal muscle
-Mostly voluntary
-A single motor neuron extends from CNS to muscle cell

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2
Q

What is the neuromuscular junction?

A

Synapse between axon terminal of somatic motor neuron & motor end plate of skeletal muscle fiber.

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3
Q

How does an action potential occur at the neuromuscular junction?

A

Neuronal action potential opens voltage-gated Ca2+ channels causing exocytosis of acetylcholine from axon terminal. The EPP opens voltage-gated Na+ channels that always produces a sarcolemmal action potential.

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4
Q

What kind of receptors does the sarcolemma have? Are they excitatory or inhibitory?

A

Nicotinic Acetylcholine receptors; excitatory/tonic control

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5
Q

What kind of receptor is the nAChR?

A

Ionotropic receptor/ receptor-channel: binding of ACh allows depolarization

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6
Q

What is an end-plate potential (EPP)?

A

A graded potential that is always excitatory

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7
Q

What is the life cycle of acetylcholine at the. neuromuscular junction?

A

-ACh made from choline and acetyl CoA
-In synaptic cleft, ACh broken down by acetylcholinesterase
-Choline transported back into axon terminal to make ACh

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8
Q

What are the characteristics of visceral motor (autonomic) neurons?

A

-Controls involuntary effectors
-Pre & Post ganglionic neurons extend from CNS to cell
-Two branches: sympathetic & parasympathetic

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9
Q

What is autonomic tone?

A

Normal balance between the SNS & PSNS branches

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10
Q

Most internal organs are under __________ control.

A

Antagonistic.

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11
Q

What is the SNS & PSNS inputs to the pupil of the eye?

A

SNS: dilate
PSNS: constrict

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12
Q

What is the SNS & PSNS inputs to heart rate?

A

SNS: increase (tachycardia)
PSNS: decrease (bradycardia)

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13
Q

What is the SNS & PSNS inputs to the lung bronchioles?

A

SNS: dilate
PSNS: constrict

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14
Q

What is the SNS & PSNS inputs to GI tract motility & secretion?

A

SNS: Decrease
PSNS: increase

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15
Q

What is the SNS & PSNS inputs to the exocrine pancreas?

A

SNS: Decrease secretion
PSNS: Increase secretion

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16
Q

What is the SNS & PSNS inputs to insulin secretion?

A

SNS: Decrease secretion
PSNS: Increase secretion

17
Q

What are the systems that are only innervated by the sympathetic branch?

A

-Sweat glands
-Smooth muscle of most blood vessels

18
Q

What NT is secreted by the pre-ganglionic neuron in both the SNS & PSNS?

A

Acetylcholine

19
Q

What is the type of receptor found on post-ganglionic neurons in both the SNS & PSNS?

A

Nicotinic AChR

20
Q

What NT does the post-ganglionic neuron of the PSNS secrete?

A

Acetylcholine

21
Q

What NT does the post-ganglionic neuron of the SNS secrete?

A

Norepinephrine

22
Q

What is the type of receptor found on target cells of the SNS?

A

Adrenergic receptors

23
Q

What is the type of receptor found on target cells of the PSNS?

A

Muscarinic

24
Q

What does the Alpha-1 subtype of adrenergic receptors do?

A

Vasoconstriction

25
Q

What does the Alpha-2 subtype of adrenergic receptors do?

A

-Inhibit digestive system functions

26
Q

What does the Beta-1 subtype of adrenergic receptors do?

A

Cardiac muscle (excitatory)

27
Q

What does the Beta-2 subtype of adrenergic receptors do?

A

-Vasodilation
-Bronchodilation

28
Q

What are varicosities?

A

The end of autonomic postganglionic neurons that store & release NT

29
Q

What is the life cycle of Norepinephrine at a sympathetic neuroeffector junction?

A

-NE synthesized from Tyrosine & stored in vesicles
-Action potential opens voltage-gated Ca2+ channels and allows exocytosis of NE
-NE can be transported back into varicosity by being repackaged in vesicle or broken down by MAO

30
Q

What are chromaffin cells?

A

Postganglionic neurons in the sympathoadrenal pathway that release epinephrine into the blood to activate “fight-or-flight” response.