5.1.1 Communication and homeostasis

Question 1

what happens to the liver when temp rises

Answer 1

activity decreases
reduces heat energy given off metabollic process

Question 2

what happens to hair on skin when your body temp rises

Answer 2

lie flat

Question 3

what happpens to blood vessels when your temp rises

Answer 3

vasodilate close to surface of skin to release more heat

Question 4

what does the hypothalmus do

Answer 4

monitors body temp

Question 5

2 ways the hypothalmus recieves inputs

Answer 5

monitors body temp of blood
recieves nervous signals from thermoreceptors to measure skin temp

Question 6

stimulus response pathway

Answer 6

stimulus- detected a receptor
sensory neurons
central nervous system - for processing
motor neurones
response- effector e.g muscle or glands

Question 7

negative feedback

Answer 7

reversal of any changes in internal environment to return to an optimium steady state / “normal state”

Question 8

positive feedback

Answer 8

increases any changes that is deletected by receptors

Question 9

examples of positive feedback

Answer 9

hypothermia
dilation of cervix at end of pregnancy

Question 10

ectotherms

Answer 10

body temp fluctuates with external temperature

Question 11

advantages of ectotherms

Answer 11

use less food in respiration
need less food
greater proportion of energy used for growth - grow quickly

Question 12

disadvantages of ectotherms

Answer 12

less active in cooler temperatures
may not be capable of activity in winter months
can’t live at poles

Question 13

what do ectotherms do if they’re too hot

Answer 13

orientate body away from sun
hide in burrow
alter body shape
increase body movement

Question 14

what do ectotherms do if they’re too cold

Answer 14

expose body to sun
orientate body to sun

Question 15

what is an endotherm

Answer 15

maintain body temp within strict limits
independant of external temperature

Question 16

advantages of an endotherm

Answer 16

constant body temp so enzymes work effectively
activity possible even when cool
inhabit colder parts of planet

Question 17

disadvantges of an endotherm

Answer 17

enzyme used up to maintain constant temp
more food required
less energy used in growth

Question 18

features/adaptations of endotherms

Answer 18

use internal sources of heatto maintain body temp
many chemical reactions in the body are exergenic
show behavioural and physiological adaptations

Question 19

what happens to your breathing when temp increases

Answer 19

increases- pant to help exchange hot air

Question 20

what happens to liver activity when body temp decreases

Answer 20

activity increases so more metabolism occurs and gives out heat

Question 21

what happens to blood vessels when body temp decreases

Answer 21

vasoconstrict
muscles constrict and blood vessels constrict
less blood is in contact with the external environment

Question 22

what happens to the muscles when body temp decreases

Answer 22

contract of skeletal muscles - shivering
increased respiration to give out heat

Question 23

what happens to skin and hair when body temp decreases

Answer 23

no sweating
erector pili muscles contract raise hairs
traps air next to skin which is easily warmed

Question 24

heat gain center

Answer 24

controls mechanism which increase body temp

Question 25

awheat loss center

Answer 25

controls mechanism which reduces body temp

Question 26

how does organism lose heat

Answer 26

`evaporation of water
conduction to surroundings
convection to surroundings
radiation to surroundings

Question 27

how does organism gain heat

Answer 27

waste heat from cell respiration
conduction from surroundings
convection from surroundings
radiation from surroundings

Question 28

benefits of multiple feedback mechanisms

Answer 28

more control
faster response

Question 29

positive feedback definition

Answer 29

mechanism that amplifies a small change into a big change

Question 30

example of positive feedback

Answer 30

oxytocin triggering contractions

Question 31

why is the hypothalmus an important part of the brain for thermoregulation

Answer 31

recieves info from peripheral receptors on the skin
monitors external temps compared to internal temps
signals effectors in the skin and muscles to respond appropriately

Question 32

what percentage of cells in the pancreas are islets of langerhans

Answer 32

5%