Motivation

Hunger Three hunger factors –Biological –Psychosocial –Genetic

Hunger Biological Physiological changes in blood chemistry and signals from digestive organs that provide feedback to the brain, which, in turn triggers us to eat or stop eating –Hunger comes from Peripheral and Central Cues

Hunger Peripheral Cues Changes in blood chemistry or signals from digestive organs –Stomach Monitors the amount and kinds of nutrients our body needs in order to restore fuel Stomach’s walls are distended and their stretch receptors signal fullness or time to stop eating

Hunger Liver –Monitors nutrients, especially glucose, in blood –When level of glucose falls, we are hungry; when level rises, we are full Intestines –Responds to the presence of food by secreting hormones, CCK (cholecystokinin), which inhibits eating

Hunger Fat cells –Secrete a hormone that is monitored by the brain –Brain signals the person to eat or stop eating so that a certain level of body fat remains constant over a person’s lifetime

Hunger Central Cues Come from the activity of chemicals and neurotransmitters in different areas of the brain –Hypothalamus Many different cells that are involved in a number of different behaviors having to do with motivation, such as thirst, sexual, behavior, and regulation of hunger

Hunger Lateral Hypothalamus –Group of cells that regulates hunger by creating feelings of being hungry Ventromedial Hypothalamus –Group of cells that regulates hunger by creating feelings of satiety, or fullness Galanin- stimulates by eating fat Norepineprine- stimulates by eating carbohydrates

Hunger Genetic Factors –Come from inherited instructions found in our genes –Determines the number of fat cells or metabolic rates of burning off the body’s fuel, which pushes us toward being normal, overweight, or underweight

Hunger Fat cells –People who inherit a larger number of fat cells have the ability to store more fat and are more likely to be fatter than average Metabolic rate –How efficiently our bodies break food down into energy and how quickly our bodies burn off that fuel

Hunger Set point –Certain level of body fat that our bodies strive to maintain constant throughout our lives Weight regulating genes –Plays a role in influencing appetite, body metabolism, and secretion of hormones that regulate fat stores

Hunger Psychosocial Factors –Learned associations We do not eat because we are hungry, but because of other factors –Socio-cultural influences Pressures to be thin Having money to eat –Personality traits Bulimia, anorexia, depression

Sexual behavior Three factors of sexual behavior –Genetic –Biological –Psychological

Sexual behavior Genetic Sex Factors Include inherited instructions for the development of sexual organs, secretion of sex hormones, and the writing of neural circuits that control sexual reflexes –Sex chromosome Contain instructions for determining the sex of the child

Sexual behavior Human egg always contains an X chromosome Human Sperm can have either X or Y chromosomes Males- XY Females- XX

Sexual Behavior Differentiation –Embryo is the same for the first four weeks Y chromosome has instructions for growing testes that produce testosterone –Testosterone triggers the development of the male sex organ and programs the hypothalamus for puberty The second X chromosome contains instructions for developing ovaries, which do not contain testosterone

Sexual behavior Biological influences –Sex hormones- chemicals secreted by the glands Males- androgens, testosterone –Secondary sexual characteristics- facial and pubic hair, muscle growth, and lowered voice Females- estrogen –Pubic hair, breast development, widening of the hips

Sexual behavior Psychological factors –Sexual or gender identity Individuals subjective experience and feelings of being either a male or a female –Gender role Traditional or stereotypic behaviors, attitudes, and personality traits that society designates as feminine or masculine

Sexual behavior Sexual orientation –Refers to whether a person is sexually aroused primarily by members of his or her own sex, the opposite sex, or both sexes –Genetic or environmental?