AP Biology : Understanding the Autonomic and Somatic Divisions

Study concepts, example questions & explanations for AP Biology

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Example Questions

Example Question #6 : Divisions Of The Nervous System

Somatic motor neurons are found in which section of the spinal cord?

Possible Answers:

Dorsal root ganglion

Ventral horn

Lateral horn

Dorsal horn

Correct answer:

Ventral horn

Explanation:

The nervous system has two principle divisions for function and two principle divisions for structure. Structurally, there are the central and peripheral nervous system divisions. Functionally, there are the somatic and autonomic divisions.

The spinal cord is found in the central nervous system, and is structurally divided into afferent sensory neurons and efferent motor neurons. Sensory neuron cell bodies are found in the dorsal root ganglion, while somatic motor neurons are found in the ventral horn of the spinal cord.

Example Question #1 : Understanding The Autonomic And Somatic Divisions

Which division of the nervous system only innervates skeletal muscle?

Possible Answers:

Parasympathetic nervous system

Sympathetic nervous system

Somatic nervous system

Peripheral nervous system

Correct answer:

Somatic nervous system

Explanation:

The nervous system has two principle divisions for function and two principle divisions for structure. Structurally, there are the central and peripheral nervous system divisions. Functionally, there are the somatic and autonomic divisions.

The somatic nervous system is responsible for voluntary actions, namely the innervation of skeletal muscle. The autonomic nervous system is responsible for all involuntary actions, including smooth muscle contraction, glandular stimulation, and other functions.

The peripheral nervous system carries both somatic and autonomic signals, innervating the entire periphery (not just skeletal muscle). The sympathetic and parasympathetic divisions of the nervous system are both autonomic. Though they innervate some skeletal muscles, they also play keys roles in other bodily functions, such as heart rate and blood pressure regulation.

The somatic nervous system is the only division to only innervate skeletal muscle.

Example Question #2 : Divisions Of The Nervous System

A sensory/receptor cell in the somatic nervous system would likely come from an __________, while a sensory/receptor cell in the autonomic nervous system would likely come from a(n) __________.

Possible Answers:

eye . . . nose

external receptor such as an eye, ear, or nose . . . internal receptor such as a chemoreceptor, baroreceptor, or thermoreceptor

internal receptor such as a chemoreceptor, baroreceptor, or thermoreceptor . . . external receptor such as an eye, ear, or nose

internal receptor such as an eye, ear, or nose . . . external receptor such as a chemoreceptor, baroreceptor, or thermoreceptor

Correct answer:

external receptor such as an eye, ear, or nose . . . internal receptor such as a chemoreceptor, baroreceptor, or thermoreceptor

Explanation:

The somatic nervous system is responsible for chiefly voluntary, conscious behavior, such as choosing a reaction to external stimuli sensed by one of the traditional five senses. The autonomic nervous system is responsible for involuntary bodily function, and can respond to sensations such as gas concentrations in the blood, changes in blood pressure, and slight deviations in body temperature, among many others. 

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