Autonomic nervous system fibers are involved in all of the following except:

• A. Stimulation of glandular secretion
• B. Adjustment of pupil diameter
• C. Regulation of heart rate
• D. Control of skeletal muscle contraction

Answer: (D)

Verified step by step guidance

1. Understand the role of the autonomic nervous system (ANS): The ANS is responsible for involuntary control of bodily functions, such as glandular secretion, pupil diameter adjustment, and heart rate regulation. It operates independently of conscious control.
2. Differentiate between the autonomic nervous system and the somatic nervous system: The somatic nervous system controls voluntary movements, including skeletal muscle contraction, while the autonomic nervous system controls involuntary functions.
3. Analyze the options provided: The first three options (stimulation of glandular secretion, adjustment of pupil diameter, and regulation of heart rate) are all functions of the autonomic nervous system. These processes are involuntary and regulated by either the sympathetic or parasympathetic divisions of the ANS.
4. Focus on the exception: Skeletal muscle contraction is under voluntary control and is regulated by the somatic nervous system, not the autonomic nervous system. This makes it the correct answer to the question.
5. Conclude the reasoning: Since the autonomic nervous system does not control skeletal muscle contraction, this option is the exception among the choices provided.