5.3 Homeostasis and thermoregulation Flashcards Preview

A Level Biology > 5.3 Homeostasis and thermoregulation > Flashcards

Flashcards in 5.3 Homeostasis and thermoregulation Deck (34):
1

what is homeostasis?

process of maintaining our internal environment within narrow limits. Dynamic equilibrium

2

why is homeostasis important?

chemical reactions must take place within the body and they can only take place if conditions are right

3

what conditions must be maintained?

chemicals
pH
temperature
water balance

4

what systems do organisms use to monitor and respond to changes from the steady state of the body?

chemical and electrical systems

5

what do chemoreceptors detect?

chemical changes

6

what do baroreceptors detect?

pressure changes

7

what do thermoreceptors detect?

temperature changes

8

what is an effector of chemoreceptors and why?

muscles
push blood containing CO2 to lungs getting rid of carbonic acid and restoring pH balance

9

what is the baroreceptors effector and why?

SAN
initiates decrease when a rise is detected by baroreceptors

10

receptors are important in homeostasis in detecting what?

changes to internal and external environment

11

what is convection?

transfer of heat in a gas or liquid by upward movement of warm air or liquid

12

what is conduction?

transfer of heat from a warmer solid object to a cooler one in direct contact

13

what is radiation?

transfer of heat as infrared rays

14

what is evaporation?

when liquid changes to a gas and has a cooling effect

15

what do ectotherms use to warm their bodies and core temperature?

environment

16

what organisms do ectotherms include?

invertebrates
fish
amphibians
reptiles

17

many ectotherms in water don't need to thermoregulate, why?

high heat capacity of water means the temp of their environment doesn't fluctuate much

18

why do ectotherms need to warm to a specific temperature?

need to warm to a temp when metabolic reactions happen fast enough to be active e.g. to catch prey

19

one behavioural adaptation of ectotherms is to lay in the sun and orientate their body why?

increase sa exposed to sun to take in as much heat as possible

20

give an example of an ectotherm displaying the behavioural adaptation of laying in the sun and orientating their body:

lizards
bask in the sun for long periods in other to get warm enough to move fast and hunt

21

how do insects show the ectotherms behavioural adaptation of using the sun to warm?

spread wings to increase sa to take in heat in order to get warm enough to fly

22

(behavioural) some ectotherms press their bodies against warm ground, why?

heat from conduction

23

(behavioural) moths and butterfly's do what in order to warm their muscles to take flight?

vibrate their wings

24

what behavioural adaptations do ectotherms have to decrease core temp?

shelter in shade
dig burrows
press against cold rocks
orientate so minimum area is exposed to sun
minimise movement
go into water

25

what is a physiological adaptation some ectotherms have regarding their colour?

dark colours absorb more radiation
so lizards in colder climates tend to be darker to gain more heat

26

(physiological) some ectotherms alter their heart rate in order to do what?

increase or decrease metabolic rate in order to regulate temperature

27

(endotherms) the hypothalamus detects temperature changes in what?

the blood

28

(endotherms) temperature receptors in the skin detect changes in what?

surface temperature

29

what do endotherms rely upon to warm their bodies and maintain a stable temperature?

metabolic processes

30

what behavioural adaptations do endotherms share with ectotherms?

bask in the sun
press themselves against warm surfaces (conduction)
dig burrows
go in water to cool
hibernation

31

what additional behavioural adaptations do humans (endotherms) have to stay warm?

wear clothes
build homes for shelter
heating systems to warm their house

32

what are the three physiological cooling responses endotherms use?

vasodilation
increased sweating
reducing insulating effect of hair

33

how do endotherms use vasodilation? (cooling)

arterioles at skin surface dilate in warm temperatures
shunt vessels constrict forcing blood through capillary networks near skins surface, causing skin to cool due to increase radiation

34

how do endotherms use sweating? (cooling)

increased temp sweat spreads across skin as it evaporates heat is lost cooling the blood near the surface

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