BioPsych Ch. 10 Review

Hypovolemia induces thirst by inducing production of which hormone?

Angiotensin II

Describe how bulimia nervosa resembles drug addiction

Bulimia shares many similarities with drug addiction. Eating tasty foods activate the same brain areas as addictive drugs, such as the nucleus accumbens

When food distends the duodenum, the duodenum releases which hormone

Cholecystokinin

How does cholecystokinin limit meal size?

Cholecystokinin limits meal size by constricting muscles in the stomach and the duodenum. This makes you feel full quicker causing you to eat less. Another way it limits meal size is by stimulating a cell in the hypothalamus which then activates a neurotransmitter that sends a message to the brain telling your body that it is full.

Chronically high insulin levels decrease appetite

False

Renin is released from the posterior pituitary

False

The main signal to end a meal is high glucose levels in the blood

False

Describe three mechanisms we have for increasing our body temperature

Find a warmer place. Put on more clothing. Fluff out your fur. Become more active. Shiver. Increase metabolism. Huddle or cuddle with others.

Describe the different causes and mechanisms of osmotic and hypovolemic thirst

Osmotic thirst is caused by an increased concentration of solutes in the extracellular fluid, either by increased salt intake, or water loss. Osmotic thirst is detected by neurons in the OVLT that cause increased release of vasopressin (which decreases urine output and raises blood pressure) and increased activity in the LPO to initiate drinking, preferably of pure water. When you lose a significant amount of body fluid by bleeding, diarrhea, or sweating, the body will release hormones, including vasopressin and angiotensin II, that constrict blood vessels. When blood volume decreases, kidneys release the hormone rennin, which splits a portion off angiotensinogen (a large protein in the blood) to form angiotensin I, which is then converted into angiotensin II; this hormone constricts blood vessels in order to reverse the loss of blood volume. Angiotensin II triggers hypovolemic thirst (thirst based on low volume). During hypovolemic thirst the body needs to replenish both water and lost solutes such as salt. Whereas an animal with osmotic thirst needs water, one with hypovolemic thirst can't drink much pure water because it would dilute its body fluids.

Briefly describe the function of the lateral hypothalamus.

The lateral hypothalamus controls insulin secretion, alters taste responsiveness, and facilitates feeding in other ways

Why did mammals evolve a body temperature of 37 degrees Celsius?

They benefit from a high temperature because they seldom need to cool themselves by much.

Newborn animals survive at first on mother's milk

True

The solutes inside and outside a cell produce an osmotic pressure

True

Eating salty pretzels would most likely result in

a craving for plain water

A cycle of food-deprivation following by overeating characterizes

bulimia

Which of the following would result in an increase in body weight

damage to the paraventricular nucleus

A drug that stimulates melanocortin receptors would most likely

decrease meal size

The first digestive site that absorbs a significant amount of nutrients is the

duodenum

After damage to the lateral hypothalamus, animals:

eat less

Animals with damage in or near the ventromedial hypothalamus gain weight

even if they eat the same amount as a normal animal.

After damage to the preoptic area, an animal

fails to shiver and sweat sufficiently

Obesity in Prader-Willi syndrome is linked to a problem with

ghrelin

Rats with damage to the paraventricular nucleus (PVN) eat ____ compared to normal rats.

larger meals

The temperature required by reproductive cells of birds and most mammals is

lower than the rest of the body

A person most likely to shiver when the

skin and the preoptic area are both cold

Ghrelin is associated with ____ in the periphery and ____ in the brain

stomach contractions, excitation of the arcuate nucleus

Aldosterone and angiotensin II together change the properties of ____, neurons in the nucleus of the tractus solitarius.

taste receptors