Chapter 10 - Temperature, Thirst and Hunger

Question 1

homeostasis

Answer 1

regulation of temperature and other biological processes that keep body within 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

the adaptive way the body changes its set points depending on the situation

Question 5

how does allostasis differ from homeostasis

Answer 5

homeostasis is keeping the body within a set point, allostasis shifts the body’s set point depending on situation

Question 6

basal metabolism

Answer 6

the energy used to maintain a constant body temperature while at rest (2/3 of our total energy)

Question 7

poikilothermic

Answer 7

“cold blooded” - body temperature matches environmental temperature

Question 8

what kinds of animals are poikilothermic?

Answer 8

amphibians, reptiles and most fish (except sharks and large fish like tuna)

Question 9

homeothermic

Answer 9

“warm blooded” - body temperature is regulated by physiological mechanisms

Question 10

what kinds of animals are homeothermic?

Answer 10

mammals and birds

Question 11

how do animals cool their bodies physiologically?

Answer 11

evaporation. by sweat (i.e humans) or by licking and panting if the species doesnt sweat (i.e. dogs)

Question 12

how do animals increase body heat?

Answer 12

shivering (muscle contractions generate heat) or decreased blood flow to the skin (stops blood from cooling too much). nonhumans fluff fur to increase insulation

Question 13

why dont our bodies temperature increase past 37 C/98 F?

Answer 13

1) requires more fuel/energy. 2) beyond 40C, proteins break bonds and lose properties

Question 14

do reproductive cells require cooler or warmer environments?

Answer 14

cooler (hence men’s scrotums hanging outside the body, and eggs being sat on instead of kept inside the too hot bird)

Question 15

which structure(s) in the brain regulate(s) temperature?

Answer 15

POA/AH - the anterior hypothalamus and preoptic area

Question 16

POA/AH

Answer 16

hpreoptic area / anterior hypothalamus

Question 17

how does the POA/AH regulate body temperature?

Answer 17

by monitoring its own temperature. if it is heated, the animal will pant or sweat, if it is cooled, it will shiver. even in a room of opposite temperature.

Question 18

how can an animal regulate body temperature after damage to the POA/AH?

Answer 18

by behavioral mechanisms like seeking warmer or cooler locations

Question 19

cause of fever

Answer 19

bacterial and viral infections

Question 20

reason of fever

Answer 20

to inhibit bacterial growth and increase survivability after infection

Question 21

cytokines

Answer 21

leukocytes->release cytokines->stimulate vagus nerve->signals hypothalamus->release of prostaglandins (necessary for fever)

Question 22

how high is too high of a fever?

Answer 22

39C (103F). 41C(109F) is life threatening

Question 23

water constitutes what percent of the mammalian body?

Answer 23

70%

Question 24

vasopressin

Answer 24

hormone released by posterior pituitary that raises blood pressure by constricting blood vessels. compensates for decreased blood volume when dehydrated. enables idneys to reabsorb water from urine

Question 25

antidiuretic hormone

Answer 25

vasopressin

Question 26

if you lacked vasopressin would you drink more or less?

Answer 26

more. you would excrete more water and would need to replace it

Question 27

osmotic pressure

Answer 27

tendency of water to flow from low concentration to high concentration across membranes

Question 28

increase of sodium causes osmotic or hypovolemic thirst?

Answer 28

osmotic

Question 29

osmotic thirst

Answer 29

thirst triggered by cells when concentration of solutes is higher within the membrane

Question 30

OVLT & SFO

Answer 30

areas important for monitoring osmotic pressure & salt content of the blood

Question 31

supraoptic nucleus & paraventricular nucleus (PVN)

Answer 31

control the rate vasopressin is released

Question 32

lateral preoptic area

Answer 32

help control drinking along with hypothalamus

Question 33

angiotension II

Answer 33

constricts blood vessels like vasporessin, due to drop in blood pressure due to bleeding, diarrhea or sweating. (low volume)

Question 34

hypovolemic thirst

Answer 34

thirst triggered by loss of salt AND water due to bleeding, diarrhea, or sweating (low volume)

Question 35

sodium-specific hunger

Answer 35

preference for salty tastes when hypovolemic thirst is present

Question 36

aldosterone

Answer 36

hormone which causes kidneys, salivary & sweat glands to retain salt when sodium reserve is low (low sodium)

Question 37

who would drink more pure water? someone with osmotic or hypovolemic thirst?

Answer 37

osmotic thirst.

Question 38

who would drink more salt water? someone with osmotic or hypovolemic thirst?

Answer 38

hypovolemic thirst

Question 39

lactase

Answer 39

enzyme necessary for metabolizing lactose

Question 40

lactose

Answer 40

the main sugar in milk

Question 41

tryptophan is increased by…? and increases…?

Answer 41

increased by carbohydrates…. increases sleepiness by triggering release of melatonin

Question 42

vagus nerve

Answer 42

conveys information about stretching of stomach walls, providing basis for satiation

Question 43

splanchic nerves

Answer 43

convey information about nutrient contents of stomach

Question 44

cholecytokinin (CCK)

Answer 44

hormone which limits meal size by constricting th sphincter (facilitating distention), signals vagus nerve to release CCK-like neurotransmitter to the brain