HO: 1-3

Question 1

stimulus

Answer 1

change in the internal or external environment

Question 2

receptor

Answer 2

cell which detects a change in the environment

Question 3

modulator/control center

Answer 3

registers the change and initiates a response (sends information)

Question 4

effector

Answer 4

structure or organ which causes the response

Question 5

response

Answer 5

action taken in response to the stimulus

Question 6

homeostasis

Answer 6

the maintenance of a stable internal environment in an organism, despite changes in the external environment

Question 7

model used to describe homeostasis

Answer 7

stimulus-response negative feedback model

Question 8

homeostasis involves

Answer 8

physiological systems, patterns of behaviour

Question 9

physiological systems

Answer 9

rely on messages within the organisms body that can act on different parts of the body

Question 10

patterns of behaviour

Answer 10

the whole organism does something to maintain homeostasis

Question 11

negative feedback

Answer 11

response that reduces the intensity of the original stimulus

Question 12

internal environment

Answer 12

refers to an organisms intracellular (cytosol), interstitial (tissue fluids) and intravascular fluids (fluids in veins)

Question 13

external environment

Answer 13

conditions outside of the body cells (includes internal fluids and conditions outside the body)

Question 14

internal factors kept within limits

Answer 14

pH, salt, water, sugar, temperature, wastes, O2, CO2

Question 15

model

Answer 15

tool to help understand a system that can’t be seen

Question 16

stimulus-response negative feedback model

Answer 16

stimulus - receptor - modulator/control center - response

Question 17

why is the model negative?

Answer 17

it feeds back an opposite stimulus to the original

Question 18

endotherm

Answer 18

an organism that can regulate its body temperature using metabolic processes, despite fluctuations in the environmental temperature. Eg. mammals and birds

Question 19

thermogenesis

Answer 19

Metabolic mechanisms that generate heat

Question 20

ectotherms

Answer 20

an organism that does not regulate its body temperature through metabolic processes - it fluctuates with the environmental temperature. Eg. reptiles and insects

Question 21

heterotherm

Answer 21

animals that exhibit characteristics of both homeothermy and poikilothermy. Eg. bats

Question 22

homeothermy

Answer 22

when homeotherms control their body temperature, making it relatively constant while the environmental temperature varies (activity is not dependent on environmental temperatures)

Question 23

poikilothermy

Answer 23

poikilotherms present a body temperature similar to the environment. Their inner temperature varies as the environment temperature does (activity is dependent on environmental temperatures)

Question 24

hibernation

Answer 24

long period of inactivity. Decrease in metabolic rate and body temp, reduces need for food and energy

Question 25

torpor

Answer 25

daily periods of inactivity. Decrease in metabolic rate and body temp, reduces need for food and energy

Question 26

Australian example of torpor

Answer 26

western pygmy possum. When below 12 degrees

Question 27

Australian example of hibernation

Answer 27

short-beaked echidna

Question 28

radiation in terms of heat transfer

Answer 28

thermal energy waves travel from the sun or from any object that is hotter and absorbed by the cooler object

Question 29

conduction in terms of heat transfer

Answer 29

requires direct contact where heat energy is transferred from a hotter object to a cooler object

Question 30

convection in terms of heat transfer

Answer 30

heat transfer via convection currents in air or water

Question 31

Evaporation in terms of heat transfer

Answer 31

heat loss via water molecules turning into gas molecules

Question 32

factors that affect amount of heat loss or gain

Answer 32

environment, SA/V ratio, temperature gradient and adaptations

Question 33

methods of heat transfer

Answer 33

radiation, conduction, convection and evaporation

Question 34

endotherms in cold environments are usually

Answer 34

large, round in shape and have small appendages

Question 35

endotherm adaptations to reduce heat loss (cold environment)

Answer 35

fur, blubber, dark pigmentation on extremities, huddling, hibernation, vaso-constriction, blood shunting, counter-current exchange systems

Question 36

endotherm adaptations to increase heat loss (hot environment)

Answer 36

shorter less dense fur, sweating, no fat, vaso-dilation, nocturnal, burrowing, thermal windows

Question 37

thermal window

Answer 37

places with large SA/V ratio and less fur, to increase sweating for heat loss

Question 38

ectotherm terrestrial adaptations

Answer 38

BSSNTPGR: basking/exposure, move to warm surfaces, move in and out of shade and burrows, activity (eg.nocturnal), torpor, change pigmentation, thermal gaping, body raising

Question 39

vasodilation

Answer 39

when surface capillaries open wider, allowing more blood from the body core to flow to the body surface where increased heat loss occurs

Question 40

vasoconstriction

Answer 40

when surface capillaries constrict, reducing blood flow from the body core to the body surface, reducing heat loss

Question 41

circulatory shunt vessels

Answer 41

can direct blood flow to the surface vessels, or away from them, increasing or decreasing heat loss from the body surface