Question 1

Which of the following tissues is NOT directly innervated by the autonomic nervous system?&#10;A) Skeletal muscle&#10;B) Kidney&#10;C) Liver&#10;D) Blood vessels&#10;E) Heart

Accepted Answer

Whereas smooth muscle and cardiac muscle are supplied by the autonomic nervous system (sympathetic and parasympathetic), skeletal muscle is supplied by nerve pathways originating in the motor cortex of the brain. While not all skeletal muscle activity is truly voluntary (e.g., reflex arcs), these pathways do not involve the autonomic nervous system per se.

Question 2

Influx of this ion into the terminal of the presynaptic nerve mediates neurotransmitter release:&#10;A) Sodium&#10;B) Potassium&#10;C) Calcium&#10;D) Magnesium&#10;E) Chloride

Accepted Answer

Calcium ions influx into the terminal of the presynaptic nerve triggers the release of neurotransmitter. Sodium and potassium ions play a role in generating the action potential, but they are not directly involved in neurotransmitter release. Magnesium ions are involved in regulating neurotransmitter release, but their influx does not cause release. Chloride ions are mainly involved in maintaining the resting membrane potential of the neuron and do not play a direct role in neurotransmitter release.

Question 3

Bronchodilation occurs in response to stimulation of this autonomic receptor:&#10;A) &#945;-1&#10;B) &#945;-2&#10;C) &#946;-1&#10;D) &#946;-2&#10;E) M-1

Accepted Answer

Bronchodilation occurs in response to stimulation of β-2 adrenergic receptors. Stimulation of α-1 adrenergic receptors causes vasoconstriction, stimulation of α-2 adrenergic receptors inhibits sympathetic activity, stimulation of β-1 adrenergic receptors results in increased heart rate and contractility, and stimulation of M-1 muscarinic receptors causes smooth muscle contraction.

Deck 9: Introduction to the Autonomic Nervous System