1. Chapter 10 Internal Regulation

2. Hunger Animals vary in their strategies of eating, but humans tend to eat more than they need at the given moment. A combination of learned and unlearned factors contribute to hunger.

3. Hunger The digestive system Saliva → carbs Stomach –Hydrochloric acid → proteins Small intestine Large intestine

4. Hunger The brain regulates eating through messages from the mouth, stomach, intestines, fat cells and elsewhere.

5. Hunger The main signal to stop eating is the distention of the stomach. –The vagus nerve –The splanchnic nerves

6. Hunger Duodenum Cholecystokinin (CCK)

7. Hunger Glucose, insulin, and glucagon levels also influence feelings of hunger (see figures 10- 14, 10-15, 10-6). Diabetes

8. Fig. 10-14, p. 311

9. Fig. 10-15, p. 311

10. Fig. 10-16, p. 311

11. Hunger Long-term hunger regulation is accomplished via the monitoring of fat supplies by the body. Leptin

12. Hunger Information from all parts of the body regarding hunger impinge into two kinds of cells in the arcuate nucleus.

13. Hunger Output from the arcuate nucleus goes to the paraventricular nucleus of the hypothalamus.

14. Hunger Input from the hunger-sensitive neurons of the arcuate nucleus is inhibitory to both the paraventricular nucleus and the satiety- sensitive cells of the arcuate nucleus itself.

15. Hunger Output from the paraventricular nucleus acts on the lateral hypothalamus. –The lateral hypothalamus controls insulin secretion and alters taste responsiveness. Animals with damage to this area refuse food and water and may starve to death unless force fed.

16. Fig. 10-20, p. 315

17. Hunger The lateral hypothalamus contributes to feeding

18. Fig. 10-22, p. 316

19. Hunger Ventromedial hypothalamus → satiety

20. Hunger People with a mutated gene for the receptors melanocortin overeat and become obese. –Melanocortin is a neuropeptide responsible for hunger. Prader-Willis syndrome

21. Hunger Anorexia nervosa Bulimia nervosa Overeating and Binge-eating Disorder