BearCh15-ACRQedt - Chapter 15 The Brain and Behavior...

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Chapter 15 – The Brain and Behavior Answers to Chapter Review Questions Page 1 of 4 Copyright © 2007. Lippincott Williams & Wilkins. Ancillary material to accompany Bear et al.: Neuroscience: Exploring the Brain, 3e Question 1: Battlefield trauma victims who have lost large volumes of blood often express a craving to drink water. Why? Answer: Under conditions of lowered blood volume or pressure, kidneys secrete renin into the bloodstream. Renin in the blood promotes the synthesis of the peptide angiotensin II, which excites the neurons in the subfornical organ. The subfornical neurons stimulate the cells in the lateral area of the hypothalamus, causing an increase in vasopressin (ADH) production and an overwhelming feeling of thirst. So, to a limited extent, the kidneys control the brain. This is why battlefield trauma victims who have lost large volumes of blood crave water. Question 2: You've stayed up all night trying to meet a term paper deadline. You now are typing frantically, keeping one eye on the paper and the other on the clock. How has the periventricular zone of the hypothalamus orchestrated your body's physiological response to this stressful situation? Describe in detail. Answer: Under conditions of physiological stress, the periventricular hypothalamus secretes corticotropin-releasing hormone (CRH) into the hypothalamo-pituitary portal circulation. This triggers the release of adrenocorticotropic hormone (ACTH) into the general circulation. ACTH stimulates the release of cortisol from the adrenal cortex. Cortisol is a steroid with a significant effect on neuronal activity. It acts by mobilizing energy reserves and suppressing the immune system. In the brain, cortisol interacts with specific receptors that inhibit CRH
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BearCh15-ACRQedt - Chapter 15 The Brain and Behavior...

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