Exam 1-Thermal Relations

Question 1

conduction

Answer 1

heat transfer between two objects (solids)

Question 2

convection

Answer 2

heat transfer between solid and surrounding air

Question 3

evaporation

Answer 3

heat causing H2O to go into gas phase

Question 4

radiation

Answer 4

heat transfer

Question 5

endothermy

Answer 5

heat is internally produced

Question 6

ectothermy

Answer 6

refers to the influence of the environment on the internal body temperature of an animal

Question 7

poikilothermy

Answer 7

refers to the ability of an animal to survive at a variety of internal body temperatures

Question 8

eurythermal

Answer 8

refers to poikilotherms who can function over a wide range of internal and external temperatures

Question 9

stenothermal

Answer 9

refers to poikilotherms who can function over a narrow range of internal and external temperatures

Question 10

behavioral thermoregulation

poikilotherms

Answer 10

maintenance of a relatively constant internal temperature via certain behaviors

Question 11

behavioral thermoregulation

homeotherms

Answer 11

the use of behavior to assist in the maintenance of a relatively constant internal temperature

Question 12

expanding thermoneutral zone

Answer 12

• in order to not have to increase metab.
• insulation: make heat transfer more difficult [fat, pilomotor (fur), ptilomotor (feathers)]
• vasomotor: blood vessels (hot-exposed, dilated at skin; cold-less exposed, constricted)
• postural: taking up space (hot) vs curling up (cold)

Question 13

Thermoreceptors

Answer 13

cold: phasic, 12-35oC
warm: phasic, 25-4oC
* mammals respond

Question 14

(regulation of temperature)

hypothalamus

Answer 14

• controls much of homeostasis
• input from peripheral temp. receptors
• directly detects temp.

Question 15

(regulation of temperature)

posterior region

Answer 15

• cold response: shiver (muscle contractions), restrict blood vessels, hair stands up, insulate, change environ., posture change)
• damage: won’t be able to sense cold or do anything about it

Question 16

(regulation of temperature)

anterior region

Answer 16

• warmth response: blood vessels dilate, sweat, change posture, change environment, lower metabolism, less active
• damage: can’t sense when we’ve gone above set-point, can’t make changes (always making heat, difficult to cool down)

Question 17

performance curve

Answer 17

-pejus range: things go to pieces (avalanche) doubtful that the individual will survive (enzymes moving so fast that they’re not really binding)

Question 18

chronic physiological response

Answer 18

• poikilotherm’s recent thermal history will determine its acute response to temp. changes
• acclimatization
• acclimation

Question 19

chronic metabolism-temperature curve

Answer 19

if change is less extreme, less stress is placed upon the system (able to make changes in the system)

Question 20

fever

ectotherms and poikilotherms

Answer 20

-cold response (deliberately increasing temp.-posterior)
-increasing set-point by pyrogens (body feels cold until reaching set-point-get shivers and put layers on)
when fever breaks-sweaty

Question 21

why fevers?

Answer 21

• invaded cells likely to die
• reduces Fe (required by bacteria)
• increasing enzyme activity (somewhat)

Question 22

poikilothermic response to high temp.

Answer 22

avoidance: shade, dens, circadian rhythm

Question 23

(poikilothermic response to freezing temp.)

production of antifreeze compounds

Answer 23

• colligative (concentration higher can survive lower temp.) (invertebrates)
• noncolligative: glycoproteins (prevent crystals)

Question 24

(poikilothermic response to freezing temp.)

supercooling

Answer 24

• cooling of a solution below its freeing point without ice formation
• ice-nucleating agents: particles that can act as a foci for freezing initiation (ice needs a substance to crystallize on)-(used by shallow fish)

Question 25

(poikilothermic response to freezing temp.) | tolerance of freezing

Answer 25

ice (pure H2O) forms in tissues around cells increasing conc. of solutes around ice (hypertonic); then solutes move into cell---decreases freezing point

Question 26

core body temperature

Answer 26

-has much tighter regulation than peripheral body temp. 37oC -circadian rhythm: increase of 1.5-2oC during active phase -in TNZ (changes won't affect internal)

Question 27

responding to temp. above TNZ

Answer 27

-active evaporation cooling: increased heat loss via accelerated water evaporation (sweating, pantin, gular fluttering)

Question 28

(responding to temp. above TNZ) | sweating

Answer 28

- increase cutaneous evaporation by 50 fold - Na, Cl loss - humans, horses, camels, kangaroos

Question 29

(responding to temp. above TNZ) | panting

Answer 29

- increased breathing rate in response to heat stress - blood CO2 (less in blood when taking in more new air than old air-messes with pH and breathing desire) - breathing patterns

Question 30

(responding to temp. above TNZ) | gular fluttering

Answer 30

-rapid up/down oscillation of mouth, cavity floor to enhance rate of evaporation cooling by increasing air flow over moist membranes in mouth

Question 31

responding to temp. below TNZ

Answer 31

- thermogenic mechanism: used to deliberately generate heat (shivering and nonshivering) - heat conservation (regional heterothermy and countercurrent heat exchange)

Question 32

(responding to temp. below TNZ) | nonshivering

Answer 32

-brown fat: in young, metabolically active, uncoupling of oxidative phosphorylation (instead of using energy to make ATP its used to generate heat)

Question 33

(responding to temp. below TNZ) | shivering

Answer 33

- high frequency, unsynchronized (constant forming/breaking bonds) contractions and relaxations of skeletal-muscle motor units - increases heat production 4-5x resting levels

Question 34

(responding to temp. below TNZ) | regional heterothermy

Answer 34

- certain regions of the body exhibit different thermal relations than other regions - wider temp. range (usually appendages)

Question 35

(responding to temp. below TNZ) | concurrent heat exchange

Answer 35

normally: loosing heat as leaves core concurrent: blood next to each other, as heat given off its absorbed by next door blood vessel (requires flow of fluids in opposite directions to help maintain a heat gradient)