Thermoregulation

Question 1

Temperature

Answer 1

Measurement of intensity of random motion of atoms or molecules; measurement of heat

Question 2

Heat

Answer 2

Molecular kinetic energy; dependant on the number and speed of atoms

Question 3

Conduction

Answer 3

Transfer of heat through a substance that is motionless down the temperature gradient; maximized by increasing the gradient difference

Question 4

Convection

Answer 4

Heat transfer through substances with movement down the temperature gradient

Question 5

Radiation

Answer 5

Transfer of electromagnetic radiation across a long distance with no direct contact between objects; maximized by increasing surface temperature

Question 6

Evaporation

Answer 6

Energy required to change a liquid to a gas; a form of conduction

Question 7

Heat storage

Answer 7

The smaller the surface area to volume ratio the slower heat is absorbed and dissapated; influenced by surface area, temperature gradient, and specific heat conductance

Question 8

Poikilotherms

Answer 8

Body temperature fluctuates and is typically close to ambient

Question 9

Homeotherms

Answer 9

Capable of maintaining a narrow body temperature range above or below ambient

Question 10

Ectotherms

Answer 10

Rely on environmental heat sources

Question 11

Endotherms

Answer 11

Generate heat through metabolism

Question 12

Heterotherms

Answer 12

Capable of some metabolic heat production, but have a wide body temperature range; typically for torper or to conserve energy

Question 13

Regional heterothermy

Answer 13

Maintaining some parts of the body endothermically but not the rest ex: birds do not warm their feet

Question 14

Temporal heterothermy

Answer 14

Body temperature varies widely over time

Question 15

Behavioral thermoregulators

Answer 15

Generating body heat through specific behaviors typically changing body shape or position to minimize wind or maximize sun such as reptiles basking or penguins huddling

Question 16

Freeze tolerance

Answer 16

Coping with extensive freezing by allowing ice crystals to form in the body; thaw inside out and typically thaw heart last to prevent bursting

Question 17

Freeze intolerance

Answer 17

Possessing some mechanism to prevent ice formation

Question 18

Preemptive ice crystal formation

Answer 18

A form of Freeze tolerance in which extracellular fluid contains an ice nucleotide agent allowing ice crystals to form extracellularly but not intracellularly; solutes excluded from ice create a highly concentrated ecf drawing water from the icf which increases the concentration of the icf preventing freezing

Question 19

Cryoprotectants

Answer 19

A mechanism of freeze tolerance which protect cells from injury during drastic temperature changes

Question 20

Colligative cryoprotectants

Answer 20

Accumulate in high concentrations to raise the osmotic concentrations of body fluids which lowers the freezing points of the ecf which limits the amount of the total body that turns to extracellular ice ex: glycerol

Question 21

Noncolligative cryoprotectants

Answer 21

Present in low concentrations that are typically membrane protectants; preserve subcellular structure from long term damage

Question 22

Supercooling

Answer 22

A mechanism of freeze intolerant organisms in which a liquid is cooled below its freezing point without solidifying; typically used in low water organisms

Question 23

Antifreezes

Answer 23

Lower the freezing point of the ecf

Question 24

Antifreeze proteins

Answer 24

Mechanism in freeze intolerant organisms typically in polar fish; glycoproteins lower the temperature at which ice crystals enlarge, preventing the addition of water to existing ice crystals; noncolligative; typically only produced in winter because they are expensive

Question 25

TNZ thermoneutral zone

Answer 25

Comfortable resting state for homeothermic organisms

Question 26

UCT upper critical temperature

Answer 26

point at which an organism must begin cooling themselves

Question 27

LCT lower critical temperature

Answer 27

point at which an organism must begin warming themselves

Question 28

summit metabolic rate

Answer 28

highest metabolic rate at which an organism can warm itself without entering hypothermia

Question 29

vasomotor response

Answer 29

selective vasoconstriction or vasodilation of blood vessels to the periphery prior to reaching LCT or UCT; constriction in the cold and dilation in the heat; ex: jackrabbits ears

Question 30

shivering thermogenesis

Answer 30

chemical energy of muscles used for heat generation produced by antagonistic muscle groups; no work is generated energy is used for heat, energetically expensive

Question 31

torper

Answer 31

allowing the metabolic rate and body temperature to drop closer to ambient to conserve energy; body temp is highly monitored to prevent freezing

Question 32

non-shivering thermogenesis

Answer 32

brown fat oxidized to produce heat; highly vascular and rich in mitochondria; capable of quickly generating high amounts of heat; found most often in young mammals but never in birds

Question 33

countercurrent heat exchange

Answer 33

heat moves by conduction from the arterial blood to the venous blood allowing blood to flow to extremities while keeping heat in the core

Question 34

pilomotor muscles

Answer 34

muscles present in mammals or birds that can raise or lower feathers or hair to alter the thickness of the insulating layer

Question 35

limited heterothermy

Answer 35

animals with a low surface area to mass ratio are more capable of tolerating higher temperatures; allow body temperature to drop especially at night and when water is scarce because evaporative cooling is not an option

Question 36

gular fluttering

Answer 36

a type of active evaporative cooling used by birds in which they open their mouth and flutter a pouch

Question 37

active evaporative cooling

Answer 37

sweating, panting, gular fluttering, saliva spreading

Question 38

heat windows

Answer 38

specific areas on the body that permit heat loss from the body surface by radiation, convection or conduction; ex: rabbit ears

Question 39

carotid rete

Answer 39

using nasal passages to cool blood moving to the brain to prevent overheating of the brain; often in conjunction with limited heterothermy

Question 40

Hypothalmus

Answer 40

major thermoregulatory control center in the brain; the thermostat