Chapter 11: INGESTIVE BEHAVIOR

Chapter 11 provides an overview of regulatory mechanisms and describes the physiological mechanisms that govern ingestion of water and food. The opening section discusses the fluid compartments of the body, and the movement of water associated with changes in tonicity of the extracellular fluid. The second chapter section discusses the two types of thirst: that that associated with cell shrinkage and that associated with a reduced blood volume. The chapter section also discusses the neural control of thirst. The third chapter section describes the peripheral physiology of metabolism including the flow of nutrients into and out of fat during the absorptive and fasting phases. The next tow chapter sections consider the factors that start a meal and those factors (head, gastric. Liver, CCK, lepton) that terminate a meal. The next chapter section considers the neural controls of eating within the brainstem and hypothalamus.

The final chapter section considers disorders of eating in humans evident in obesity and anorexia nervosa/bulimia nervosa.

After completing the chapter, each student should be able to:

• Define homeostasis.
• Diagram the four features of a regulatory mechanism.
• Describe the fluid compartments of the body.
• Describe the hormonal events that control the secretion of water and of sodium by the kidney.
• Define thirst.
• Describe the events that produce osmometric thirst and volumetric thirst.
• Describe the absorptive and fasting phases of metabolism.
• Discuss social and environmental factors that begin a meal.
• Describe social and environmental factors that begin a meal.
• Discuss the head, gastric, and intestinal factors that stop a meal.
• Describe the research on the role of the brainstem and hypothalamus in hunger and satiety.
• Discuss the physiological factors that contribute to obesity.
• Discuss the physiological factors that contribute to anorexia and bulimia.