Biological Psychology Chapter 9: Internal Regulation PDF

Biological Psychology, 14e Chapter 9: Internal Regulation James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May...

Biological Psychology, 14e Chapter 9: Internal Regulation James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 1  Icebreaker: In The Year…. Check your pockets for a piece of change or a dollar bill. Look at the date on the item and reflect on the year (try another coin if the date is too early). Share something you were doing around that time in your life with the group. − For example: The date on the coin is 2011, this was the time you were in elementary school, and you have a memory from the playground. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 2  Chapter Objectives (1 of 3) By the end of this chapter, you should be able to: 9-1. List examples of how temperature regulation contributes to behaviors. 9-2. Define homeostasis and allostasis. 9-3. Explain why a constant high body temperature is worth all the energy it costs. 9-4. Describe the brain mechanisms of temperature control. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 3  Chapter Objectives (2 of 3) 9-5. Discuss why a moderate fever is advantageous in fighting an infection. 9-6. Distinguish between osmotic and hypovolemic thirst, including the brain mechanisms for each. 9-7. Discuss sodium-specific hunger. 9-8. Explain the genetic influences on consumption of dairy products. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 4  Chapter Objectives (3 of 3) 9-9. Discuss influences on food selection. 9-10. Describe the physiological factors that influence short-term and long-term hunger and satiety. 9-11. Describe the brain mechanisms of feeding. 9-12. Discuss common eating disorders. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 5  Module 9.1 Temperature Regulation James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 6  Introduction (1 of 3) Temperature affects many aspects of behavior. Temperature regulation is vital to the normal functioning of many behavioral processes. Homeostasis refers to temperature regulation and other biological processes that keep certain body variables within a fixed range. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 7  Temperature Regulation in the Natural World Figures 9.1–9.3 illustrate examples of temperature regulation. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 8  Homeostasis and Allostasis (1 of 2) Various biological processes that keep body variables within a fixed range − Examples: temperature, levels of water, oxygen, glucose, calcium, protein, fat, and acidity in the body Set point: a single value that the body works to maintain Negative feedback: processes that reduce discrepancies from the set point − Much of motivated behavior can be described as negative feedback. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 9  Homeostasis and Allostasis (2 of 2) Allostasis refers to the adaptive way in which the body anticipates needs depending on the situation. − Helps the body avoid errors instead of just correcting them Homeostasis and allostasis don’t work perfectly. − If they did, we would not have problems such as obesity, high blood pressure, or diabetes James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 10 Controlling Body Temperature (1 of 3) Temperature regulation is one of the body’s biological priorities. Maintaining temperature requires twice as much energy as all other activities combined. Basal metabolism − Energy used to maintain a constant body temperature while at rest James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 11 Controlling Body Temperature (2 of 3) Poikilothermic (ectothermic): idea that the body temperature matches that of the environment − Amphibians, reptiles, and most fish − The organism lacks the internal, physiological mechanisms of temperature regulation. − Temperature regulation is accomplished via choosing locations in the environment. − Although known as “cold-blooded,” organism is cold only if environment is cold. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 12 Controlling Body Temperature (3 of 3) Homeothermic (endothermic): use of internal physiological mechanisms to maintain an almost constant body temperature − Characteristic of mammals and birds − Requires energy and fuel − Sweating and panting decrease temperature. − Increasing temperature is accomplished via shivering, decreasing blood flow to the skin, and fluffing out fur to increase insulation. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 13 One Way to Cope with the Heat James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 14 Behavioral Regulation of Body Temperature James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 15  Surviving in Extreme Cold Poikilothermic animals − Death will occur if body temperature drops below freezing. Ice crystals form in cells and blood. − Amphibians and reptiles burrow underground to avoid the cold. − Some insects and fish stock blood with antifreeze compounds in winter.  Extraordinary blood-clotting ability quickly repairs ruptured blood vessels. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 16  The Advantages of Endothermy Mammals evolved to have a constant temperature of 37˚C (98˚F). − Muscle activity benefits from being as warm as possible.  Ready for vigorous activity So why not go higher if warmer is better? − Requires even more energy − Proteins in the body break their bonds and lose their useful properties at higher temperatures. − Reproductive cells require cooler temperatures. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 17  Brain Mechanisms (1 of 2) Body temperature regulation is predominantly dependent upon areas in the preoptic area/anterior hypothalamus (POA/AH). POA/AH receives input from temperature receptors throughout the body. − Heating the POA/AH leads to panting or sweating; cooling leads to shivering. − Receives input from the immune system James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 18  Major Subdivisions of the Hypothalamus and Pituitary Gland James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 19  Fever (1 of 2) Immune system delivers prostaglandins and histamines. − Causes shivering, increased metabolism, and fever POA/AH is not the only brain area involved in temperature regulation. − Primary area for controlling sweating or shivering James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 20  Fever (2 of 2) Reflects an increased body temperature set point, directed by the hypothalamus Benefits − Certain bacteria grow less vigorously. − Immune system works more vigorously. Fever of above 39˚C (103˚F) does the body more harm than good. − Fevers above 41˚C (109˚F) are life-threatening. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 21 Integration of Temperature Information by the POA/AH James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 22  Knowledge Check 9-1 How does allostasis differ from homeostasis? James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 23  Knowledge Check 9-1: Answer How does allostasis differ from homeostasis? − Homeostasis keeps certain body variables within a fixed range by reacting to changes. − Allostasis acts in advance to prevent or minimize changes. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 24  Module 9.2 Thirst James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 25  Introduction (2 of 3) Water constitutes 70 percent of the mammalian body. Water in the body must be regulated within narrow limits. Sufficient fluid is needed in circulatory system. The concentrations of chemicals in water determine the rate of all chemical reactions in the body. When you need water, axons from the hypothalamus modify the responses of more than half the cells in the cortex to increase their responses to any signal of water availability. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 26  Strategies of Water Regulation (1 of 2) Human mechanisms of water regulation vary depending on circumstances. Water can be conserved by: − Excreting concentrated urine − Decreasing sweat James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 27  Strategies of Water Regulation (2 of 2) Vasopressin is a hormone released by the posterior pituitary. − Raises blood pressure by constricting blood vessels − Helps to compensate for decreased water volume − Also known as an antidiuretic hormone (ADH) − Enables the kidneys to reabsorb water and excrete highly concentrated urine Most often, water regulation is accomplished by drinking more water than we need and excreting the rest. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 28  Osmotic Thirst (1 of 6) Two different kinds of thirst − Osmotic thirst: results from eating salty foods − Hypovolemic thirst: a thirst resulting from loss of fluids due to bleeding or sweating Fixed concentration of solutes in the body is a set point. − 0.15 M (molar) in mammals James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 29  Osmotic Thirst (2 of 6) Solutes inside and outside a cell create osmotic pressure. − Water flows across a semi-permeable membrane from an area of low solute concentration to an area of high solute concentration. − Occurs when solutes are more concentrated on one side of the membrane James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 30  Osmotic Thirst (3 of 6) Eating salty food causes sodium ions to spread through the blood and extracellular fluid of the cell. − The higher concentration of solutes outside the cell results in osmotic pressure, drawing water from the cell to the extracellular fluid. Certain neurons detect the loss of water and trigger osmotic thirst to help restore the body to its normal state. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 31  Osmotic Thirst (4 of 6) The brain detects osmotic pressure from: − Receptors around the third ventricle − The OVLT (organum vasculosum laminae terminalis) and the subfornical organ (SFO)  Detect osmotic pressure and sodium content of the blood − Receptors in the periphery, including the stomach and digestive tract James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 32 The Brain’s Receptors for Osmotic Pressure and Blood Volume James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 33  Osmotic Thirst (5 of 6) Receptors in the OVLT, subfornical organ, stomach and elsewhere relay information to two areas of the hypothalamus: − Supraoptic nucleus − Paraventricular nucleus  Both control the rate at which the posterior pituitary releases vasopressin. Receptors also relay information to the lateral preoptic area, which controls drinking. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 34  Osmotic Thirst (6 of 6) When you eat a meal, especially a salty meal, you drink at once instead of waiting until your osmotic pressure changes. The OVLT receives input from receptors in the digestive tract that inform about the food, water, and salt content, enabling it to anticipate the osmotic need. The OVLT also receives input from the tongue. Receptors in the circulation to the liver detect the osmotic concentration of the fluid, and if it is low, they signal the brain to decrease thirst. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 35 The Consequence of a Difference in Osmotic Pressure James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 36  Hypovolemic Thirst and Sodium- Specific Hunger (1 of 2) Thirst associated with low volume of body fluids Low blood volume—kidneys release enzyme renin which helps form angiotensin I. Other enzymes convert that into angiotensin II. − Like vasopressin, angiotensin II constricts blood vessels to compensate for a drop in blood pressure. − Angiotensin II stimulates neurons subconical that release angiotensin II as a neuromodulator. − Neurons in the third ventricle send axons to the hypothalamus where angiotensin II is released as a neurotransmitter. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 37 Hormonal Response to Hypovolemia James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 38  Hypovolemic Thirst and Sodium- Specific Hunger (2 of 2) Animals with osmotic thirst have a preference for pure water. Animals with hypovolemic thirst have a preference for slightly salty water. − Pure water dilutes body fluids and changes osmotic pressure. Sodium-specific hunger: strong craving for salty foods − Develops automatically to restore solute levels in the blood When the body’s sodium reserves are low, the adrenal glands release the hormone aldosterone that causes the kidneys, salivary glands, and sweat glands to retain salt. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 39  Comparison of Osmotic and Hypovolemic Thirst Table 9.1 Osmotic and Hypovolemic Thirst Type of Caused by Best Relieved by Receptor Location Thirst Osmotic High solute concentration Pure water OVLT, subfornical organ, outside cells and digestive tract Hypovolemic Low blood volume Water containing OVLT, subfornical organ, solutes kidneys and blood vessels James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 40  Discussion 9-1 In a small group, discuss the following: − Two hikers are separated and lost in the desert. One hiker is experiencing osmotic thirst and the other is experiencing hypovolemic thirst.  Which of the hikers fell and, as the result of a large gash in their leg, lost a lot of blood?  Which hiker lost their canteen 2 days ago and is dehydrated? − Later in the same day, both hikers are found by a search and rescue team.  Develop a strategy for treating the conditions of each hiker. − Jot your group’s main discussion ideas down and prepare to share them with the large group. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 41  Module 9.3 Hunger James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 42  Introduction (3 of 3) Animals vary in their eating strategies. − Predators have large digestive systems adapted to huge, infrequent meals. − Bears eat constantly. − Small birds eat only what is needed at the moment to preserve light weight for flight. Chickadees eat enough daily to increase body weight 10 percent. Then they lose it at night keeping warm. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 43 A Python Swallowing a Gazelle James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 44 A Great Tit, a Small European Bird James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 45  Digestion and Food Selection Digestive system function − Breaks down food into smaller molecules that the cells can use Digestion begins in the mouth − Enzymes in saliva break down carbohydrates. Hydrochloric acid and enzymes in the stomach digest proteins. Enzymes in the small intestine digest proteins, fats, and carbohydrates. − Digested food absorbs into the bloodstream The large intestine absorbs water and minerals. − Lubricates the remaining materials for excretion James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 46 The Human Digestive System James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 47  Consumption of Dairy Products (1 of 2) At the age of weaning, most mammals lose the intestinal enzyme lactase, which is necessary for metabolizing lactose, the sugar found in milk. Milk consumption after weaning can cause gas and stomach cramps. Declining levels of lactase may be an evolutionary mechanism to encourage weaning. James W. W. Kalat, Kalat,Biological Psychology, Biological Psychology,14th 14 Edition. th © 2023 Edition. ©Cengage. All RightsAll 2024 Cengage. Reserved. May not beMay Rights Reserved. scanned, copied not be or duplicated, scanned, copied oror posted to a publicly duplicated, accessible or posted website, accessible to a publicly in whole or in part. website, in whole or in part. 48  Consumption of Dairy Products (2 of 2) Many human adults have enough lactase to consume milk and other dairy products throughout their lifetime. Nearly all adults in China and surrounding countries lack the gene that enables adults to metabolize lactose. − Only small quantities of dairy products can be consumed. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 49 Percentage of Adults Who Are Lactose Tolerant James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 50  Food Selection and Behavior Unsubstantiated beliefs may influence food selection. − Examples:  Sugar intake increases hyperactivity in children.  Eating turkey increases body supply of tryptophan, which makes you sleepy. − Adage that fish is brain food is partly true.  Eating fish may help improve memory. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 51  Short- and Long-Term Regulation of Feeding Oral factors − The desire to taste and chew is also a motivating factor in hunger and satiety. − Chewing gum from 4500 B.C. discovered Sham feeding experiments − Everything an animal eats leaks out of a tube connected to the stomach or esophagus. − Do not reliably produce satiety James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 52  5,000-year-old gum James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 53  The Stomach and Intestines (1 of 3) The main signal to stop eating is the distention of the stomach. The vagus nerve − Cranial nerve X − Conveys information about the stretching of the stomach walls to the brain James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 54  The Stomach and Intestines (2 of 3) Duodenum − Part of the small intestine − Site of initial absorption of significant amounts of nutrients Distention of the duodenum can also produce feelings of satiety. The duodenum also releases the hormone cholecystokinin (CCK), which helps to regulate hunger. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 55  The Stomach and Intestines (3 of 3) Cholecystokinin (CCK) released by the duodenum regulates hunger by: − Closing the sphincter muscle between the stomach and duodenum and causing the stomach to hold its contents and fill faster − Stimulating the vagus nerve to send a message to the hypothalamus that releases a chemical similar to CCK James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 56  Glucose, Insulin, and Glucagon (1 of 4) Glucose − Main product of digestion − Important source of energy for the body − Nearly the only fuel used by the brain Insulin and glucagon regulate the flow of glucose into cells. Excess glucose enters the liver and fat cells. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 57  Glucose, Insulin, and Glucagon (2 of 4) Insulin is a pancreatic hormone that enables glucose to enter the cell. After a meal: − Blood glucose levels fall. − Insulin levels drop. − Glucose enters cells more slowly. − Hunger increases. − Pancreas releases glucagon. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 58 Insulin and Glucagon Feedback System James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 59 Glucose, Insulin, and Glucagon (3 of 4) Glucagon is a hormone released by the pancreas when glucose levels fall. − Stimulates the liver to convert some of its stored glycogen to glucose to replenish low supplies in the blood James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 60  Glucose, Insulin, and Glucagon (4 of 4) If insulin level stays constantly high: − Blood glucose drops and hunger increases in spite of high insulin levels. − Food is rapidly deposited as fat and glycogen. − Causes weight gain  Valuable preparation for winter in some animals  Most humans also eat more in autumn than in other seasons. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 61 Effects of Steady High Insulin Levels on Feeding James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 62 People Eat More in Fall Than in Other Seasons James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 63  Diabetes and Appetite (1 of 2) In people with type 1 diabetes, insulin levels remain constantly low, but blood glucose levels are high. − People eat more food than normal but excrete the unused glucose and lose weight. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 64  Diabetes and Appetite (2 of 2) Type 2 diabetes, which usually begins in middle age or later − Is the more common type − It occurs mostly in association with obesity and lack of exercise. − In type 2 diabetes, the pancreas produces enough insulin, but cells have become unresponsive to it. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 65 People with Untreated Diabetes Eat Much but Lose Weight James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 66  Leptin (1 of 2) Long-term hunger regulation is accomplished by the monitoring of fat supplies by the body. The body’s fat cells produce the peptide leptin, which signals the brain to increase or decrease eating. Low levels of leptin increase hunger. High levels reduce eating and increase physical and immune system activity. Puberty is triggered by a certain level of leptin during adolescence. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 67  Brain Mechanisms (2 of 2) Information from all parts of the body regarding hunger impinges onto the arcuate nucleus. The arcuate nucleus is a part of the hypothalamus containing two sets of neurons. Neurons sensitive to hunger signals Neurons sensitive to satiety signals James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 68  The Arcuate Nucleus and Paraventricular Hypothalamus Ghrelin − Neurotransmitter released in the brain − Acts on the hypothalamus to increase appetite − Triggers stomach contractions Nicotine also stimulates the satiety neurons in the arcuate nucleus. − Cigarette smoking decreases appetite. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 69  The Arcuate Nucleus Input to the satiety-sensitive cells of the arcuate nucleus − Signals of both long-term and short-term satiety − Distention of the intestine triggers neurons to release the neurotransmitter CCK. − Blood glucose stimulates satiety cells in the arcuate nucleus. − Body fat releases leptin. − NPY and AgRP block the satiety action of the paraventricular nucleus and provoke overeating. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 70  The Feeding Circuit in the Hypothalamus James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 71  Paraventricular Hypothalamus Output from the arcuate nucleus goes to the paraventricular nucleus of the hypothalamus. − Part of the hypothalamus that inhibits the lateral hypothalamus, an area important for eating − Axons from the satiety-sensitive cells of the arcuate nucleus deliver an excitatory message to the paraventricular nucleus.  Causes release of melanocortins − Cells in the lateral hypothalamus release orexin.  Orexin increases animals’ persistence in seeking food. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 72  Melanocortin Melanocortin: chemical important in limiting food intake − Deficiencies of this receptor lead to overeating. Input from the hunger cells of the arcuate nucleus: − Inhibits the paraventricular nucleus which, in turn, inhibits the lateral hypothalamus James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 73  The Lateral Hypothalamus (1 of 2) Feeding-related functions of the lateral hypothalamus − Controls insulin secretion − Alters taste responsiveness Stimulation of the lateral hypothalamus increases the drive to eat. − Damage to this area causes aversion to food. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 74 Lateral, Ventromedial, and Paraventricular Hypothalamus James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 75 Recovery After Damage to the Lateral Hypothalamus James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 76  Pathways from the Lateral Hypothalamus James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 77  The Lateral Hypothalamus (2 of 2) Many axons containing dopamine pass through the lateral hypothalamus. Axon functions − Affect the taste sensation and salivation response to tastes − Cause cortical cells to increase response to taste, smell, or sight of food − Increase pituitary gland’s hormone secretion that increases insulin secretion − Control digestive secretions James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 78  Medial Areas of the Hypothalamus Output from the ventromedial hypothalamus (VMH) inhibits feeding. − Damage to this nucleus leads to overeating and weight gain.  Rats eat normal sized meals but eat more frequently.  Increased stomach motility—stomach empties faster than normal James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 79  Effects of Hypothalamic Lesions Table 9.2 Effects of Hypothalamic Lesions Hypothalamic Area Effect of Lesion Preoptic area Deficit in physiological mechanisms of temperature regulation Lateral preoptic area Deficit in osmotic thirst due partly to damage to cells and partly to interruption of passing axons Lateral hypothalamus Undereating, weight loss, low insulin level (because of damage to cell bodies); underarousal, underresponsiveness (because of damage to passing axons) Ventromedial hypothalamus Increased meal frequency, weight gain, high insulin level Paraventricular nucleus Increased meal size, especially increased carbohydrate intake during the first meal of the active period of the day James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 80  Effects of Damage to the Ventromedial Hypothalamus James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 81  Eating Disorders Availability of tasty, high calorie foods makes animals (and people) obese, and they find other rewards less rewarding. Psychological distress does not cause weight gain. A high-fat diet before birth can result in the offspring being born with a larger than average lateral hypothalamus. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 82  Genetics and Body Weight Thin parents tend to have thin children and heavy parents tend to have heavy children. People with a mutated gene for the receptors for melanocortin overeat: melanocortin responsible for satiety Syndromal obesity: Prader-Willi syndrome: genetic condition marked by intellectual disability, short stature, and obesity: high blood levels of ghrelin Monogenic and polygenic James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 83  Weight Loss Techniques Obesity considered a disease in the United States Dieting by itself not considered reliably effective Lifestyle changes including increased exercise essential. Many supplements marketed for weight loss or memory improvement include chemicals not listed on the label, sometimes posing health risks − Many of these supplements have doubtful effectiveness. Gastric bypass surgery James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 84  Bulimia Nervosa Eating disorder in which people alternate between extreme dieting and binges of overeating − Some force vomiting after eating − Associated with increased release of ghrelin and alterations of several other hormones and transmitters − Resembles drug addiction James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 85  Anorexia Nervosa Eating disorder characterized by a refusal to eat enough to maintain a healthy body weight − Most have an exaggerated fear of getting fat − Many also engage in excessive exercise. − Have altered dopamine levels—cause versus effect? − New hypothesis for treatment—adjust temperature levels  European trials showed ¾ of patients fully recovered James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 86  Activity 9-1 In small groups of three or four students, browse Google Play for apps related to weight loss. − After browsing the apps discuss the following:  What characteristics of the apps are shared?  What characteristics of the apps are unique? Share your thoughts with the larger group and discuss the extent to which using social pressure to promote the apps is applied by the app creators. James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 87  Summary Click the link to review the objectives for this presentation. Link to Objectives James W. Kalat, Biological Psychology, 14th Edition. © 2024 Cengage. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly accessible website, in whole or in part. 88