Question

multiple choice 2 points

the autonomic nervous system controls all of the following except the ______.

parotid salivary gland
smooth muscle in the walls of the aorta
skeletal muscle in the rectus abdominis
adrenal gland
cardiac muscle in the right atrium

Explanation:

Identify the target of autonomic control

The question asks which of the listed structures is not controlled by the autonomic nervous system (ANS). The ANS regulates involuntary body functions, targeting cardiac muscle, smooth muscle, and glands.

Analyze the physiological targets

• parotid salivary gland: This is an exocrine gland regulated by autonomic (parasympathetic) signals.
• smooth muscle in the walls of the aorta: Smooth muscle is involuntarily controlled by the autonomic nervous system.
• skeletal muscle in the rectus abdominis: Skeletal muscles are under voluntary control, which is mediated by the somatic nervous system, not the autonomic nervous system.
• adrenal gland: This endocrine gland is directly innervated by sympathetic preganglionic fibers of the autonomic nervous system.
• cardiac muscle in the right atrium: Cardiac muscle is involuntarily regulated by autonomic fibers (sympathetic and parasympathetic).

Determine the correct exception

Using the Autonomic Nervous System and Voluntary Muscle concepts, we identify that the rectus abdominis is a skeletal muscle under voluntary somatic motor control. Therefore, it is the exception.

Answer:

• parotid salivary gland
• smooth muscle in the walls of the aorta
• skeletal muscle in the rectus abdominis (Correct answer)
• adrenal gland
• cardiac muscle in the right atrium