PSY 387 Chapter 9

Some set points may vary considerably over time in order to respond to changes in the environment. This adaptability is known as: a. homeothermic. b. homeostasis. c. allostasis. d. negative feedback.

Allostasis

Hypovolemia induces thirst by inducing production of which hormone? a. Insulin b. CCK c. Angiotensin II d. Prolactin

Angiotensin II

Describe how bulimia nervosa resembles drug addiction.

Eating sugary and high fat foods activates the same brain areas as addictive drugs, such as the nucleus accumbens. Animals that experience periodic food deprivation followed by a diet of sweet foods eventually begin to eat greater quantities of food. These animals react with behaviors similar to those seen in individuals withdrawing from some addictive drugs. More importantly drug addicts who cannot get drugs sometimes overeat as a substitute, and food-deprived people or animals become more likely than others to use drugs.

Humans spend about one-third of their total energy maintaining body temperature.

False

An animal has trouble digesting its food after damage to the: a. lateral hypothalamus. b. pineal gland. c. medial part of the hypothalamus. d. occipital cortex.

Lateral hypothalamus

Which of the following groups of people would most likely benefit from taking leptin? a. obese people with faulty leptin receptors b. obese people who fail to produce leptin c. normal obese people d. anorexic patients

Obese people who fail to produce leptin

Briefly describe the function of the lateral hypothalamus.

The lateral hypothalamus controls insulin secretion, alters taste responsiveness, and facilitates feeding in other ways. Damage to the lateral hypothalamus causes an animal to refuse food and water.Contributions of the lateral hypothalamus include: altering the taste of food (when one is hungry, food tastes better), causing cortical cells to increase their response to taste, smell, or sight of food, controlling insulin secretion, controlling digestive secretions.

Why does the level of glucose in the blood vary so little under normal circumstances? a. Glucose does not leave the blood to enter the cells of the body. b. The liver can convert stored nutrients into glucose. c. Mammals learn to eat only foods that contain glucose. d. Manufacturing glucose is a lengthy process, so the body uses it slowly.

The liver can convert stored nutrients into glucose.

What is one reason why animals with a lesion in the lateral hypothalamus eat so little? a. All the food they eat is immediately converted into fat storage. b. They are constantly active and over-responsive to sensory stimuli. c. They have low levels of blood sugar. d. They experience a decreased cortical response to the smell and sight of food.

They experience a decreased cortical response to the smell and sight of food.

A moderate fever can increase an individual's chance of surviving a bacterial infection.

True

Some cases of obesity can be traced to a single gene that affects melanocortin receptors.

True

The paraventricular nucleus normally inhibits meal size.

True

Vasopressin increases blood pressure by constricting the blood vessels.

True

A Danish study correlating the weights of 540 adopted children with various adoptive and biological relatives found: a higher correlation with biological relatives during childhood but a higher correlation with adoptive relatives in adulthood. b. the same correlation with biological relatives and adoptive relatives. c. a higher correlation with biological relatives than adoptive relatives. d. a higher correlation with adoptive siblings than with biological siblings.

a higher correlation with biological relatives than adoptive relatives.

Electrical stimulation of a rat's lateral hypothalamus would most likely result in: a. an increase in food seeking behaviors. b. a decrease in chewing and other reflexes associated with eating. c. damage to dopamine-containing axons passing through it. d. a decrease in food seeking behaviors.

an increase in food seeking behavior

Many kinds of information impinge onto two kinds of cells in one nucleus of the hypothalamus, which is regarded as the "master area" for control of appetite. That area is the: a. suprachiasmatic nucleus. b. arcuate nucleus c. solitary nucleus d. sexually dimorphic nucleus.

arcuate nucleus

How do amphibians and reptiles control their body temperature? a. by choosing an appropriate area of the environment b. by changing the reflectivity of their skin c. they cannot d. by shivering and sweating

by choosing an appropriate area of the environment

Eating salty pretzels would most likely result in a. a greater salt craving. b. a craving for plain water. c. hypovolemic thirst. d. drinking sugary liquids.

craving for water

In response to infection, leukocytes release proteins called: a. leptin. b. cholecystokinin. c. insulin. d. cytokines.

cytokines

More Native American Pimas are overweight now than in the early 1900s because of a change in which aspect of their lives? a. Education b. Stress c. Exercise d. Diet

diet

Damage to the ventromedial hypothalamus leads to: a. eating less. b. eating more when presented with a normal or sweetened diet. c. eating the same amount; there are no changes. d. becoming less finicky about what they eat.

eating more when presented with a normal or sweetened diet

Vasopressin and angiotensin II are similar in that they both promote a. decreased blood pressure. b. decreased thirst. c. increased urination. d. increased blood pressure.

increased blood pressure

Which hormone controls the rate at which glucose leaves the blood and enters the cells? a. CCK b. Aldosterone c. Glucagon d. Insulin

insulin

Output from the paraventricular nucleus acts on the: a. preoptic area. b. ventromedial hypothalamus. c. baroreceptors. d. lateral hypothalamus.

lateral hypothalamus

The temperature required by reproductive cells of birds and most mammals is: a. fluctuating in direct opposition to changes in body temperature. b. the same as the internal organs of the body. c. higher than the rest of the body. d. lower than the rest of the body.

lower than the rest of the body

Homeothermic organisms include: a. reptiles and fish. b. amphibians and fish. c. amphibians and reptiles. d. mammals and birds.

mammals and birds

The physiological changes that defend body temperature are mainly controlled by the: a. pineal body and preoptic area. b. preoptic area and posterior hypothalamus. c. preoptic area and anterior hypothalamus. d. parietal cortex and hypothalamus.

pre optic area and anterior hypothalamus

One way by which food in the duodenum inhibits appetite is by: a. releasing glucagon. b. inhibiting the release of CCK. c. breaking down CCK into inactive components. d. releasing CCK.

releasing cck

Taste and other mouth sensations contribute to: a. satiety. b. overeating. c. hunger. d. thirst.

satiety

The vagus and splanchnic nerves help to control feeding by relaying information to the brain from the: a. muscles. b. liver. c. stomach. d. taste buds.

stomach

The areas around the third ventricle can detect chemicals circulating in the blood because: a. these areas have low concentrations of solutes themselves. b. these areas are not protected by a blood-brain barrier. c. these cells maintain a higher internal temperature than the rest of the body. d. there is so much more blood here than anywhere else in the brain.

these areas are not protected by a blood-brain barrier

Fen-Phen", an appetite suppressant drug, acts by ____ serotonin, norepinephrine, and dopamine. a. stimulating release of b. breaking down c. blocking reuptake of d. blocking receptors for

Blocking reuptake of

Which organisms, if any, use behavioral means to regulate their body temperature? a. both poikilothermic and homeothermic b. homeothermic, but not poikilothermic c. neither poikilothermic nor homeothermic d. poikilothermic, but not homeothermic

Both poikilothermic and homeothermic

When food distends (swells) the duodenum, the duodenum releases which hormone? a. Aldosterone b. angiotensin II c. CCK d. Prolactin

CCK

What happens when insulin levels are high? a. Fat supplies are depleted. b. Glucose entry into the cells increases. c. Fat supplies are converted to glucose, which enters the blood. d. The sphincter muscle between the stomach and the duodenum opens.

Glucose entry into the cells increases

Describe the different causes and mechanisms of osmotic and hypovolemic thirst.

Hypovolemic thirst is thirst associated with low volume of body fluids such as too much sweating, bleeding or diarrhea. It is triggered by the release of the hormones vasopressin and angiotensin II, which constrict blood vessels to compensate for a drop in blood pressure. Angiotensin II stimulates neurons in areas adjoining the third ventricle. Neurons in the third ventricle send axons to the hypothalamus where angiotensin II is also released as a neurotransmitter. Animals with hypovolemic thirst have a preference for slightly salty water as pure water dilutes body fluids and changes osmotic pressure. Sodium-specific hunger, a strong craving for salty foods which develops automatically to restore solute levels in the blood when individuals or animals eat salty food. Osmotic thirst occurs when solutes are more concentrated on the outside of the cell. This causes water to move from high concentration inside the cell to the outside that has a lot of solutes. For example if a person eats a salty meal, the stomach will detect high levels of sodium. The high levels of salt outside the cells increases osmotic pressure causing the cells to shrink as water leaves from inside the cell. This change is pressure is detected by cells in the hypothalamus (OVLT and SFO). The OVLT and SFO also stimulates the supraoptic nucleus and paraventricular nucleus of the hypothalamus. The PVN also stimulates the lateral preoptic area that causes individuals to feel thirsty and go to get a drink of water. The PVN of the hypothalamus also signals the release of vasopressin from the posterior pituitary. Vasopressin increases blood pressure by constricting blood vessels to compensate for decreased water volume in cells. Vasopressin also causes the kidneys to reabsorb water and excrete very concentrated urine. When an individual feels thirsty with osmotic thirst, they will drink pure water.

What kind of thirst is produced by an increased concentration of solutes in the blood? a. Osmotic b. Postprandial c. Hypovolemic d. Non-homeostatic

Osmotic

After damage in and around the ventromedial hypothalamus, animals are more likely to: a. overeat and gain weight. b. be slow in their digestion. c. produce low levels of the hormone CCK. d. refuse food and lose weight.

Overeat and gain weight

Tryptophan enters the brain by an active-transport protein that it shares with ____ and other large amino acids. a. melatonin b. glucose c. phenylalanine d. lactose

Phenylalanine

Describe the major brain mechanisms of eating and hunger.

The hypothalamus regulates feeding behavior. One section, the arcuate nucleus, initiates the feeling of hunger using the neurotransmitter ghrelin when the stomach sends a signal that the body requires nutrients. The lateral hypothalamus is associated with the sensation of taste, which reinforces eating behaviors. It also secretes insulin so that glucose can be transferred into cells. When satiated, the paraventricular nucleus of the hypothalamus inhibits the lateral hypothalamus so that feeding behaviors cease and over-eating is prevented. Finally, the ventromedial region of the hypothalamus affects the timing of feeding. The hunger-sensitive cells of the arcuate receive input from the taste pathway and from ghrelin released by the stomach during food deprivation.The satiety-sensitive cells of the arcuate nucleus receive input for both short-and long-term satiety. Input includes CCK released from the intestines, and insulin release from pancreas to regulate both blood glucose and body fat. Leptin also provides input to the arcuate nucleus. The arcuate nucleus activates paraventricular nucleus (PVN). The PVN inhibits the lateral hypothalamus (an area important for eating) and is involved in satiety. α-Melanocyte stimulating hormone is released from the satiety-sensitive cells of the arcuate nucleus to the PVN. Deficiencies in melanocortin receptors or PVN damage cause individuals to eat larger than normal meals because they do not respond to satiety signals. Inhibitory transmitters from the hunger-sensitive cells of the arcuate nucleus include GABA, neuropeptide Y (NPY), and agouti-related peptide (AgRP). They inhibit the PVN and the satiety-sensitive cells of the arcuate nucleus to increase hunger and stimulate eating behaviors. NPY cells also have a pathway to the orexin-producing cells of the lateral hypothalamus. Orexin stimulates activity and the onset of meals but has a minor overall effect on feeding behavior. The lateral hypothalamus controls insulin secretion, alters taste responsiveness, and facilitates feeding in other ways. Damage to the lateral hypothalamus causes an animal to refuse food and water. The ventromedial hypothalamus (VHM) regulates eating. And stimulates overeating and weight gain.

Describe three mechanisms we have for increasing our body temperature

The mechanisms are mostly behavioral but it also includes internal regulation that causes basal metabolism to change. There are many behaviors such as finding a warmer place, putting on more clothing. fluffing out your fur/body hair, become more active, shivering and huddling or cuddling with others. The hypothalamus helps to regulate these behaviors and internal processes.

What happens when blood levels of insulin are extremely low? a. Appetite is low. b. There is excess glucose in the blood, but it cannot enter the cells. c. The brain shifts to proteins as its main source of fuel. d. Glucose leaves the blood to be stored as fat.

There is excess glucose in the blood, but it cannot enter the cells

The brain can anticipate an osmotic need before the rest of the body actually experiences it: a. through detection of highly concentrated urine. b. because the stomach can detect high levels of sodium. c. because of the change in blood pressure. d. because of the rate of vasopressin release.

because the stomach can detect high levels of sodium.

How do adult mammals with damage to the preoptic area regulate their body temperature? a. pharmacologically b. not at all c. physiologically d. behaviorally

behaviorally

Chronically high insulin levels lead to increased appetite by: a. causing a high percentage of available glucose to be stored as fat. b. preventing glucose from entering the cells. c. directly altering the responses of the taste buds. d. lowering body temperature, increasing the need for nutrition.

causing a high percentage of available glucose to be stored as fat.