chapter 12

Question 1

homeostasis

Answer 1

the process by which the body’s substances and characteristics are maintained at their optimal level

Question 2

ingestive behavior

Answer 2

eating or drinking

Question 3

system variable

Answer 3

a variable that is controlled by a regulatory mechanism for example, temperature in a heating system

Question 4

set point

Answer 4

the optimal value of the system variable in a regulatory mechanism

Question 5

detector

Answer 5

in a regulatory process, a mechanism that signals when the system variable deviates from its set point

Question 6

correctional mechanism

Answer 6

in a regulatory process, the mechanism that is capable of changing the value of the system variable

Question 7

negative feedback

Answer 7

a process whereby the effect produced by an action serves to diminish or terminate that action; a characteristic of regulatory system

Question 8

satiety mechanism

Answer 8

a brain mechanism that causes cessation of hunger or thirst produced by adequate and available supplied of nutrients or water

Question 9

intracellular fluid

Answer 9

the fluid contained within cells; monitored by receptors measuring cell volume

Question 10

extracellular fluid

Answer 10

all body fluids outside the cells; interstitial fluid, blood plasma, and cerebrospinal fluid

Question 11

intravascular fluid

Answer 11

the fluid found within the blood vessels; monitored by receptors measuring blood volume

Question 12

interstitial fluid

Answer 12

the fluid that bathes the cells, filling the space between the cells of the body

Question 13

hypovolemia

Answer 13

reduction in the volume of the intravascular fluid

Question 14

osmometric thirst

Answer 14

thirst produced by an increase in the osmotic pressure of the interstitial fluid relative to the intracellular fluid, thus producing cellular dehydration

Question 15

osmoreceptor

Answer 15

a neuron that detects changes in the solute concentration of the interstitial fluid that surrounds it

Question 16

volumetric thirst

Answer 16

thirst produced by hypovolemia

Question 17

angiotensin

Answer 17

a peptide hormone that constricts blood vessels, causes the retention of sodium and water, and produces thirst and a salt appetite

Question 18

glycogen

Answer 18

a polysaccharide often referred to as animal starch; stored in the liver and muscle; constitutes the short-term store of nutrients

Question 19

insulin

Answer 19

a pancreatic hormone that facilitates entry of glucose and amino acids into the cell, conversion of glucose into glycogen and transport of fats into adipose tissue

Question 20

glucagon

Answer 20

a pancreatic hormone that promotes the conversion of liver glycogen into glucose

Question 21

triglycerides

Answer 21

the form of fat storage in adipose cells; consists of a molecule of glycerol joined with three fatty acids

Question 22

glycerol

Answer 22

a substance derived from the break down of triglycerides

Question 23

fatty acid

Answer 23

a substance derived from the breakdown of triglycerides along with glycerol; can be metabolized by most cells of the body except for the brain

Question 24

fasting phase

Answer 24

the phase of metabolism during which nutrients are not available from the digestive system; glucose, amino acids, and fatty acids are derived from glycogen, protein, and adipose tissue

Question 25

absorptive phase

Answer 25

the phase of metabolism during which nutrients are absorbed from the digestive system; glucose and amino acids constitute the principal source of energy for cells during this phase, and excess nutrients are stored in adipose tissue in the form of triglycerides

Question 26

ghrelin

Answer 26

a peptide hormone released by the stomach that increases eating; also produced by neurons in the brain

Question 27

duodenum

Answer 27

the first portion of the small intestine, attached directly to the stomach

Question 28

glucoprivation

Answer 28

a dramatic fall in the level of glucose available to cells; can be caused by a fall in the blood level of glucose or by drugs that inhibit glucose metabolism

Question 29

lipoprivation

Answer 29

a dramatic fall in the level of fatty acids available to cells; usually caused by drugs that inhibit fatty acid metabolism

Question 30

cholecystokinin (CCK)

Answer 30

a hormone secreted by the duodenum that regulates gastric motility and causes the gallbladder to contract; appears to provide a satiety signal transmitted to the brain through the vagus nerve

Question 31

peptide YY 3-36 (PYY)

Answer 31

a chemical produced by cells in the gastrointestinal tract and released by the small intestine after a meal in amounts proportional to the calories that were just ingested; serves as a satiety signal

Question 32

hepatic portal vein

Answer 32

the vein that transports blood from the digestive system to the liver

Question 33

ob mouse

Answer 33

a strain of mice whose obesity and low metabolic rate are caused by a mutation that prevents the production of leptin

Question 34

leptin

Answer 34

a hormone secreted by adipose tissue; decreases food intake and increases metabolic rate, primarily by inhibiting NPY-secreting neurons in the arcuate nucleus

Question 35

decerebration

Answer 35

a surgical procedure that severs the brain stem, disconnecting the hindbrain from the forebrain

Question 36

melanin-concentrating hormone (MCH)

Answer 36

one of two peptide neurotransmitters found in a system of lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate

Question 37

orexin

Answer 37

one of two peptide neurotransmitters found in a system of lateral hypothalamic neurons that stimulate appetite and reduce metabolic rate. also called hypocretin

Question 38

neuropeptide Y (NPY)

Answer 38

a peptide neurotransmitter found in a system of neurons of the arcuate nucleus that stimulate feeding and insulin and glucocorticoid secretion; decreases the breakdown of triglycerides; and decreases body temperature

Question 39

agouti-related protein

Answer 39

a neuropeptide that acts as an antagonist at MC4Rs and increases eating

Question 40

arcuate nucleus

Answer 40

a nucleus in the base of the hypothalamus that controls secretion of the anterior pituitary gland; contains NPY-secreting neurons involved in feeding and control of metabolism

Question 41

paraventricular nucleus

Answer 41

a nucleus of the hypothalamus located adjacent to the dorsal third ventricle contains neurons involved in the control of the autonomic nervous system and the posterior pituitary gland

Question 42

CART

Answer 42

cocaine and amphetamine-regulated transcript; a peptide neurotransmitter found in a system of neurons of the arcuate nucleus that inhibit feeding

Question 43

a-melanocyte-stimulating hormone (a-MSH)

Answer 43

a neuropeptide that act as an agonist at MC4Rs and inhibits eating

Question 44

melanocortin-4 receptor (MC4R)

Answer 44

a receptor found in the brain that binds with a-MSH and agouti-related protein; plays a role in the control of appetite

Question 45

anorexia nervosa

Answer 45

a disorder that most frequently afflicts young women; exaggerated concern with overweight that leads to excessive dieting and often compulsive exercising; can lead to starvation

Question 46

bulimia nervosa

Answer 46

bouts of excessive hunger and eating often followed by forced vomiting or purging with laxatives; sometimes seen in people with anorexia nervosa

Question 47

binge eating disorder

Answer 47

a disorder that includes bouts of excessive eating