Which of the following best describes the primary function of the reticular activating system (RAS) in the endocrine system?

• A. It stores and releases neurotransmitters for muscle contraction.
• B. It produces hormones that control metabolism.
• C. It regulates arousal and alertness by controlling the sleep-wake cycle.
• D. It filters waste products from the bloodstream.

Answer: (C)

Verified step by step guidance

1. Understand that the reticular activating system (RAS) is a network of neurons located in the brainstem, not a gland or organ of the endocrine system.
2. Recognize that the primary function of the RAS is related to regulating states of consciousness, particularly arousal and alertness.
3. Recall that the RAS plays a crucial role in controlling the sleep-wake cycle, which influences when we are awake and alert versus when we are asleep.
4. Eliminate options that describe functions unrelated to the RAS, such as hormone production, neurotransmitter storage for muscle contraction, or filtering waste products.
5. Conclude that the best description of the RAS's primary function is its role in regulating arousal and alertness by controlling the sleep-wake cycle.