Question 1

Most visceral organs are innervated by only parasympathetic nerve fibers.

Accepted Answer

Most visceral organs are innervated by both sympathetic and parasympathetic nerve fibers, which have opposing effects on the organs.

Question 2

Dual innervation of organs with nerve fibers whose actions oppose each other enables precise control over an organ's activity,like having both an accelerator and a brake to control the speed of a car.

Accepted Answer

Dual innervation allows for fine-tuned control over an organ's activity by providing opposing nerve fibers that can either stimulate or inhibit the organ's function, similar to how an accelerator and a brake in a car can control its speed.

Question 3

Unlike autonomic efferent output,visceral efferent output operates within the realm of consciousness and voluntary control.

Accepted Answer

Visceral efferent output is part of the autonomic nervous system, which operates largely outside of conscious control.

Question 4

Nicotinic receptors are activated by the tobacco plant derivative nicotine,whereas muscarinic receptors are activated by the mushroom poison muscarine.

Accepted Answer

Nicotinic receptors are indeed activated by nicotine, whereas muscarinic receptors are activated by acetylcholine and not muscarine.

Question 5

Unlike the two-neuron chain of autonomic nerve fibers,the axon of a motor neuron is continuous from its origin in the CNS to its ending on skeletal muscle.

Accepted Answer

The statement is true. The axon of a motor neuron extends uninterrupted from its cell body in the central nervous system (CNS) to its termination at a skeletal muscle fiber, allowing for voluntary movement control.

Question 6

Very short preganglionic fibers end on the cells of an organ itself.

Accepted Answer

Very short preganglionic fibers end on the cells of a ganglion, where they synapse with postganglionic neurons. It is the postganglionic fibers that end on the cells of an organ itself.

Question 7

Sympathetic and parasympathetic postganglionic fibers release the same neurotransmitter,acetylcholine (ACh).

Accepted Answer

Sympathetic postganglionic fibers primarily release norepinephrine (noradrenaline), whereas parasympathetic postganglionic fibers release acetylcholine (ACh).

Question 8

Norepinephrine serves as a neurotransmitter in the CNS and is released from the adrenal medulla as a hormone as well.

Accepted Answer

Norepinephrine can function as both a neurotransmitter in the central nervous system (CNS) and as a hormone released from the adrenal medulla into the bloodstream.

Question 9

Nerve and muscle cells do not come into direct contact at a neuromuscular junction.

Accepted Answer

At a neuromuscular junction, there is a small gap called the synaptic cleft between the nerve ending and the muscle fiber. Neurotransmitters are released by the nerve ending into the synaptic cleft and then bind to receptors on the muscle fiber, triggering muscle contraction. Therefore, nerve and muscle cells do not come into direct contact at a neuromuscular junction.

Question 10

Almost all neurally controlled effector organ responses are directly mediated by one of two neurotransmitters: acetylcholine or norepinephrine.

Accepted Answer

Almost all neurally controlled effector organ responses are directly mediated by one of two neurotransmitters: acetylcholine or norepinephrine.

Question 11

Within a neuromuscular junction,the axon terminal splits into multiple fine branches,each of which ends in an enlarged knoblike structure called the terminal button.

Accepted Answer

This is a correct description of the structure of a neuromuscular junction.

Question 12

The pons within the brain stem is the region most directly responsible for autonomic output.

Accepted Answer

The pons is involved in many functions including respiration, sleep, and relaying information between different parts of the brain. However, the region most directly responsible for autonomic output is the medulla oblongata, which is located just below the pons.

Question 13

The specialized underlying portion of the muscle cell membrane is called the sensory end plate.

Accepted Answer

The specialized underlying portion of the muscle cell membrane is called the motor end plate, not the sensory end plate.

Question 14

Amyotrophic lateral sclerosis (ALS)is also known as polio.

Accepted Answer

ALS is not the same as polio. Polio is caused by a virus while ALS is a progressive neurodegenerative disease.

Question 15

The result of infection with poliovirus is paralysis of the muscles innervated by the affected neurons.

Accepted Answer

Poliovirus attacks and damages motor neurons in the spinal cord, leading to muscle weakness and paralysis.

Question 16

Long postganglionic fibers originate in the ganglion chain and end on the effector organs.

Accepted Answer

Long postganglionic fibers indeed originate in the ganglion chain and extend all the way to the effector organs they innervate. This type of innervation is characteristic of the parasympathetic division of the autonomic nervous system. In contrast, the sympathetic division often uses short postganglionic fibers that synapse with the target tissues directly or through various plexuses.

Question 17

The peripheral nervous system has two subdivisions: the sympathetic and the parasympathetic nervous systems.

Accepted Answer

The peripheral nervous system is divided into the somatic and autonomic nervous systems; the autonomic system is further divided into the sympathetic and parasympathetic systems.

Question 18

Cardiac muscle,smooth muscle,most exocrine glands,some endocrine glands,and adipose tissue are innervated by the autonomic nervous system,the involuntary branch of the peripheral efferent division.

Accepted Answer

The statement is true. Autonomic nervous system innervates cardiac muscle, smooth muscle, most exocrine glands, some endocrine glands, and adipose tissue.

Question 19

Motor neurons are considered the final common pathway because the only way any other parts of the nervous system can influence skeletal muscle activity is by acting on these motor neurons.

Accepted Answer

Motor neurons are the final common pathway through which the nervous system influences skeletal muscle activity. Other parts of the nervous system can only influence muscle activity by acting on these motor neurons. Therefore, the statement is true.

Question 20

An antagonist binds with the receptor,preventing the neurotransmitter from binding and causing a response,yet the antagonist itself produces no response.

Accepted Answer

This is an accurate description of how an antagonist works. It blocks the receptor from being activated by the neurotransmitter, but does not activate the receptor itself, resulting in no response.

Quiz 7: The Peripheral Nervous System - Efferent Division

Most visceral organs are innervated by only parasympathetic nerve fibers.

Dual innervation of organs with nerve fibers whose actions oppose each other enables precise control over an organ's activity,like having both an accelerator and a brake to control the speed of a car.

Unlike autonomic efferent output,visceral efferent output operates within the realm of consciousness and voluntary control.

Nicotinic receptors are activated by the tobacco plant derivative nicotine,whereas muscarinic receptors are activated by the mushroom poison muscarine.

Unlike the two-neuron chain of autonomic nerve fibers,the axon of a motor neuron is continuous from its origin in the CNS to its ending on skeletal muscle.

Very short preganglionic fibers end on the cells of an organ itself.

Sympathetic and parasympathetic postganglionic fibers release the same neurotransmitter,acetylcholine (ACh).

Norepinephrine serves as a neurotransmitter in the CNS and is released from the adrenal medulla as a hormone as well.

Nerve and muscle cells do not come into direct contact at a neuromuscular junction.

Almost all neurally controlled effector organ responses are directly mediated by one of two neurotransmitters: acetylcholine or norepinephrine.

Within a neuromuscular junction,the axon terminal splits into multiple fine branches,each of which ends in an enlarged knoblike structure called the terminal button.

The pons within the brain stem is the region most directly responsible for autonomic output.

The specialized underlying portion of the muscle cell membrane is called the sensory end plate.

Amyotrophic lateral sclerosis (ALS)is also known as polio.

The result of infection with poliovirus is paralysis of the muscles innervated by the affected neurons.

Long postganglionic fibers originate in the ganglion chain and end on the effector organs.

The peripheral nervous system has two subdivisions: the sympathetic and the parasympathetic nervous systems.

Cardiac muscle,smooth muscle,most exocrine glands,some endocrine glands,and adipose tissue are innervated by the autonomic nervous system,the involuntary branch of the peripheral efferent division.

Motor neurons are considered the final common pathway because the only way any other parts of the nervous system can influence skeletal muscle activity is by acting on these motor neurons.

An antagonist binds with the receptor,preventing the neurotransmitter from binding and causing a response,yet the antagonist itself produces no response.