One week of Notes (3-1-16 and 3-3-16)
One week of Notes (3-1-16 and 3-3-16) PSYCH 3240
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This 6 page Class Notes was uploaded by Lucy Stevens on Thursday March 3, 2016. The Class Notes belongs to PSYCH 3240 at Clemson University taught by Dr. Claudio Cantalupo in Spring 2016. Since its upload, it has received 15 views. For similar materials see PSYCH 3240 in Psychlogy at Clemson University.
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Date Created: 03/03/16
Chapter 6 3-1-16 Taste o 5 primary tastes- sweet, sour, salty, bitter, umami o Heavily innate senses; born with these tastes o More complex taste sensations are combinations of 5 primaries o Nucleus of the Solitary Tract (Medulla): sense travels here after hitting the taste buds on the tongue and then heads to the insula o Insula (Cerebral Hemisphere): sometimes known as the 5 th lobe of the brain. Neurons here become active and you become consciously aware of the tastes. Major hubs for large scale brain networks. o Contributes to dietary selection in three additional ways Sensory-Specific Satiety: the more of a specific food a person eats, the less appealing a food becomes Encourages a varied diet balanced diet Controlled by the Nucleus of Solitary Tract (NST) in the medulla. Learned Taste Aversions: the avoidance of foods associated with illness or poor nutrition May be one reason chemotherapy patients loose appetite Learned Taste Preferences: preferences for flavor of foods that contain important nutrients (e.g. Vitamin B) Animals learn to prefer the flavor of a food enriched with thiaminepresumably makes them feel better The Digestive Process o Begins with saliva in the mouth by enzymes o HCL and pepsin break it down in the stomach If food irritates the stomach, regurgitation occurs If no irritation occurs, toxins reach the area postrema of brain-induces projectile vomiting o Most digestion occurs in the small intestine (especially the duodenum) Carbohydratesglucose Proteinsamino acids All are transferred to the liver via the hepatic portal vein FatsFatty acids and glycerol o Large intestine reabsorbs water from the food before it is excreted from the body. The Two Phases of the Feeding Cycle o Absorptive Phase: Glucose increases Parasympathetic activation Pancreas secretes insulin Glucose enters body cells; glucose stored in the liver and muscles as glycogen; fat stored in adipose cells as triglycerides o Fasting Phase: Glucose decreases Sympathetic activation Pancreas secretes glucagon Glycogen transformed to glucose (for brain); stored fat released as fatty acids (for body) and glycerol (for brain, after conversion to glucose) Two Major Signals for Hunger 1. Glycoprivic Hunger: deficit in glucose 2. Lipoprivic Hunger: deficit in fatty acids o Low Glucose and fatty acids signaled via vagus nerve to the Nucleus of the Solitary Tract (NST) and the Area Postrema (both in the medulla) o Information is then relayed to Arcuate Nucleus (AN)ParaVentricular Nucelus (PVN) and Lateral Hypothalamus (LH): when neurons here become active we become hungryIncrease in the release of neuropeptide Y in LH and PVN. Powerful stimulate for eating and reduces metabolism (and even sexual motivation) Another powerful stimulant for eating: Grelin (produced by the stomach and gets it into the blood supply where it will reach the regions in the hypothalamus and will activate the AN; this then activates the PVN and the LH which causes you to feel hungry) Signals that End Eating o Stretch receptors in the stomach-signal via vagus nerve to medulla (NST and Area Postrema)decrease of neuropeptide Y in PVN and LH. Then you start to feel less hungry o Cholecystokinin (CCK)- peptide hormone released when food passes through the duodenumvagus nervemedulladecrease of neuropeptide Y in PVN and LH o Peptide YY 3-36PYY) intestine-secreted hormonereaches Arcuate Nucleus through bloodstream- slower action than CCK o High levels of nutrients in blood-detected by livervagus nervemedulla (NST and area postrema)decrease of neuropeptide Y in PVN and LH Long Term Regulation of Body Fat o Leptin (hormone secreted by fat cells) Amount of leptin in blood is proportional to % of body fat Increased leptin in blooddecrease in neuropeptide Y in PVN and LH Decreased leptin in bloodincrease in neuropeptide Y in PVN and LH Leptin levels is about 4 times higher in obese than non- obese people may have fewer active leptin receptors in PVN and LH Chapter 6 through page 171 in book Chapter 7 3-3-16 Biology of Sex (Book Up to Page 197) Is sex a physiological drive (like hunger and thirst)?? o Main difference: sex is not essential for survival of the individual o Similarities: Arousal and satiation Role of hormones Involvement of specific brain areas Phases of Sex Cycle 1. Excitement 2. Plateau 3. Orgasm 4. Resolution Refractory Phase (more specific to males) -Somewhat related to sensory-specific satiety -Certain amount of time after orgasm that has to relax in order for the male to receive excitement phase again. -Broad spectrum of time differences for each individual Sensory-Specific Satiety: the more of a specific food a person eats, the less appealing the food becomes -Encourages a varied diet Coolidge Effect (Male Specific): quicker return to sexual arousal for a male when a new female is introduced -Observed in many species -“Cheap sperms, expensive eggs” theory -a male can potentially have a large number of children quickly by mating with different females Roles of Hormones on Sexual Activity Sex Hormones Androgen: male characteristics and functions o Testosterone= major sex hormone in males Estrogen: female characteristics and functions Testosterone and Sexual Activity Evidence from castration (removal of the gonads) studies Sexual behavior decreases; clearly shows that hormones are very important variables for triggering sexual behavior Testosterone appears necessary for male sexual behaviors, but amount required is minimal Females initiate sex more at mid-cycle when both estrogen and testosterone levels are elevated o Testosterone may be more important than estrogen for this in women Testosterone increases as a result of sexual activity in both males and females. o Cause-effect relationship by the way testosterone and sexual activity is still unclear Brain Structures and Sex Network of brain structures are involved in sexual activity Medial PrOptic Area (MPOA) of Hypothalamus o Stimulation of MPOA in rats increased copulation o Sexual Dimorphic Nucleus of MPOA Larger in male rats Depends on prenatal exposure to testosterone Medial Amygdala: active during copulation in both males and females; stimulation causes dopamine release in MPOA VentroMedial Nucleus (VMN) of Hypothalamus: active during copulation in females; destruction reduces responsiveness to males Neurotransmitters and Sex Dopamine and Serotonin increases MPOA in rats. Norepinephrine increases in men and women during sex. Dopamine increases in the Nucleus Accumbens o In male rats it increases also with new female (Coolidge Effect) Sensory Stimuli and Sex Interplay of internal (hormone) conditions and external stimuli. o Tactual; Auditory; Visual Body symmetry is another important determinant of sexual attraction Bilateral Symmetry has nothing to do with sex as far as we can tell. It really just has to do with moving around in a medium. Sponges: don’t need to be symmetric. An animal that swims to catch prey better be streamlined. May be indicative of genetic fitness o Olfactory (smell) Pheromones= airborne chemicals released by an animal that may have a physiological or behavioral effect on another animal of the same species. Female gypsy moth attracts males from 2 miles away. What about people?? VomeroNasal Organ (VNO): we do have in human noses as well. It is microscopic. Very large in animals like cats and dogs. Pheromones are detected by the VNO VNO sends signals to MPOA and VentroMedial nucleus to hypothalamus. McClintock study on menstrual synchrony Found that women living together had menstrual cycles at the same time. Menstrual synchrony in human females due to pheromones. Humans have a VNO too Microscopic in size Generates electrical potentials to suspend pheromones Experiment: Men rate photographs and voice recordings of women higher when sniffling inhalers containing suspected pheromones from the women. Men rate t-shirts of more attractive women highest on sexiness- smell itself not pleasant Men using after-shave containing suspected male pheromone report more sexual activity than controls. Pheromonal influence on sexual behavior of humans is still controversial.
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