1. Name the two regions of the CNS primarily responsible for regulating homeostasis, and identify their role in regulating homeostasis. Use the following key terms: cardiac control, respiratory control, sleep/wake cycle, hunger/thirst center, body temperature control, hormone control of pituitary gland, brain stem, hypothalamus.

Answer 1

The two regions of the central nervous system (CNS) primarily responsible for regulating homeostasis are the hypothalamus and the brain stem.

1. Hypothalamus: This region plays a critical role in maintaining homeostasis by regulating various physiological processes. It is involved in:

   • Cardiac control: The hypothalamus helps regulate heart rate and blood pressure.
   • Respiratory control: It influences breathing patterns and can activate respiratory responses based on metabolic needs.
   • Sleep/wake cycle: The hypothalamus regulates circadian rhythms, impacting sleep and alertness.
   • Hunger/thirst center: The hypothalamus detects nutrient levels and hydration status, driving the mechanisms of hunger and thirst.
   • Body temperature control: It acts as the body’s thermostat, initiating responses to maintain a stable internal temperature.
   • Hormone control of the pituitary gland: The hypothalamus produces hormones that regulate the release of hormones from the pituitary gland, impacting numerous bodily functions.

2. Brain Stem: The brain stem is responsible for many autonomic functions essential for life and plays a supportive role in homeostasis:

   • It houses centers that control basic functions like heart rate (cardiac control) and respiratory rate (respiratory control).
   • It also regulates reflexes that contribute to maintaining balance and posture, which can indirectly support overall homeostasis.

Together, the hypothalamus and the brain stem ensure the body maintains a stable internal environment by coordinating vital physiological functions.