Chapter 10

Question 1

homeostasis

Answer 1

temperature regulation and other biological processes that keep body variables within a fixed range

Question 2

set point

Answer 2

a single value that the body works to maintain

Question 3

negative feedback

Answer 3

processes that reduce discrepancies from the set point

Question 4

allostasis

Answer 4

adaptive way in which the body changes its set points depending on the situation (much of this control depends on hypothalamus)

Question 5

basal metabolism

Answer 5

energy used to maintain a constant body temperature while at rest (requires about twice as much energy as all other body processes combined)

Question 6

poikilothermic

Answer 6

amphibians, reptiles, and most fish; body temperature matches environment and is controlled by behavioural mechanisms

Question 7

homeothermic

Answer 7

mammals and birds; use physiological mechanisms to maintain a nearly constant body temperature despite changes in temperature in the environment

Question 8

Preoptic area/anterior hypothalamus, POA/AH

Answer 8

physiological changes that defend body temperature depend on these areas which send output to the hindbrain’s raphe nucleus which controls these mechanisms

Question 9

Vasopressin aka antidiuretic hormone (ADH)

Answer 9

released by posterior pituitrary; raises blood pressure by constricting blood vessels which helps compensate for decreased blood volume when we don’t have enough water; enables kidneys to reabsorb water from urine

Question 10

osmotic pressure

Answer 10

tendency of water to flow across a semi permeable membrane from areas of low concentration of solutes to areas of high concentration

Question 11

osmotic thirst

Answer 11

certain neurons detect loss of water (i.e. eating salty food = + solutes in blood drawing water out of cells and into extracellular fluid) and trigger osmotic thirst which helps restore normal state

Question 12

Organum vasculosum laminae terminalis (OVLT)

Answer 12

important for detecting osmotic pressure with subfornical organ (SFO), and salt content of the blood; receives input from brain itself and receptors in digestive tract, enabling brain to anticipate an osmotic need before the rest of the body experiences it

Question 13

supraoptic nucleus

Answer 13

part of hypothalamus; messages from OVLT and SFO; controls rate at which posterior pituitary releases vasopressin

Question 14

paraventricular nucleus

Answer 14

part of hypothalamus; messages from OVLT and SFO; controls rate at which posterior pituitary releases vasopressin

Question 15

lateral preoptic area

Answer 15

part of hypothalamus that controls drinking

Question 16

angiotensin II

Answer 16

constricts blood vessels, compensating for drop in blood pressure (renin splits angiotensinogen)

Question 17

hypovolemic thirst

Answer 17

thirst based on low volume; need to restore lost salts and water

Question 18

lactase

Answer 18

intestinal enzyme necessary for digesting lactose

Question 19

lactose

Answer 19

sugar found in milk

Question 20

sham-feeding

Answer 20

everything an animal swallows leaks out a tube connected to esophagus or stomach; does not produce satiety

Question 21

vagus nerve

Answer 21

stomach conveys satiety messages to the brain via the vagus and splanchic nerves; conveys information about the stretching of the stomach walls

Question 22

splanchic nerves

Answer 22

stomach conveys satiety messages to the brain via the vagus and splanchic nerves; convey information about the nutrient contents of the stomach

Question 23

duodenum

Answer 23

part of the small intestine adjoining the stomach; releases OEA that stimulates vagus nerve

Question 24

cholecystokinin (CCK)

Answer 24

reseased by any kind of food in the duodenum; limits meal size by 1) constricting sphincter muscles between stomach and duodenum, casing stomach to fill more quickly than usual, 2) stimulates vagus nerve to send signals to hypothalamus causing cells there to release a shorter version of CCK

Question 25

Insulin

Answer 25

pancreatic hormone; enables glucose to enter the cells, except for the brain cells; insulin levels rise before a meal in preparation for a rush of additional glucose; high levels decrease appetite

Question 26

Glucagon

Answer 26

pancreatic hormone; stimulates the liver to convert some of its stored glycogen to glucose to replenish low supplies in the blood

Question 27

arcuate nucleus

Answer 27

area of hypothalamus; one set of neurons sensitive to hunger signals and one set sensitive to satiety signals

Question 28

Ghrelin

Answer 28

neurotransmitter; binds to same receptors as growth hormone releasing hormone; released by stomach during a period of food deprivation where it triggers stomach contractions; acts on hypothalamus to decrease appetite and enhance learning

Question 29

melanocortin

Answer 29

melanocortin receptors in the paraventricular nucleus are important for limiting food intake; deficiencies lead to over eating

Question 30

neuropeptide Y

Answer 30

inhibitory transmitter; input from hunger-sensitive neurons of arcuate nucleus is inhibitory to PVN and setiety sensitive cells of arcuate nucleus itself

Question 31

agouti-related peptide

Answer 31

inhibitory transmitter; input from hunger-sensitive neurons of arcuate nucleus is inhibitory to PVN and setiety sensitive cells of arcuate nucleus itself

Question 32

lateral hypothalamus

Answer 32

input from PVN; compared to a crowded train station due to many clusters of neurons and passing axons; controls insulin secretion, taste responsiveness, and facilitates feeding

Question 33

ventromedial hypothalamus (VMH)

Answer 33

output inhibits feeding; damage (and loss of output) can lead to drastically increased weight

Question 34

bulimia nervosa

Answer 34

a condition in which people alternate between periods of binging and strict dieting (many people with bulimia also induce themselves to vomit)