endothermic regulation

Question 1

where does the hypothalamus receive information from?

Answer 1

• thermoreceptors in the hypothalamus
• peripheral thermoreceptors in the skin

Question 2

what do hypothalamus thermoreceptors do?

Answer 2

detect temperature of the blood as it passes through the brain

Question 3

what do peripheral thermoreceptors do?

Answer 3

detect temperature of external air at skin surface

Question 4

what is the role of thermoreceptors?

Answer 4

send nerve impulses along sensory neurones to the hypothalamus which sends impulses along motor neurones to effectors

Question 5

what do effectors do?

Answer 5

respond to restore body temperature back to normal

Question 6

what is the role of the hypothalamus?

Answer 6

keeps core body temp in dynamic equilibrium (37 degrees)

Question 7

what is the main advantage of having two different thermoreceptors in different locations?

Answer 7

allows body to respond to change throughout the body

Question 8

how do endotherms regulate body temperature

Answer 8

through a nervous response

Question 9

state the path of travel for nerve impulses

Answer 9

sensory neurone –> brain –> hypothalamus –> effector

Question 10

how does sweating regulate temperature?

Answer 10

• increase in water
• increases latent vaporisation
• acts as a cooling effect

Question 11

how does vasodilation regulate temperature?

Answer 11

• arterioles dilate due to muscle contraction
• constricts vessels supplying capillaries
• increases blood near skin surface which radiates more heat energy
• increases temperature

Question 12

how does vasoconstriction regulate temperature?

Answer 12

• arterioles near skin surface restrict
• decreases blood near skin surface and increases further away
• less heat energy radiated
• decreases temperature

Question 13

how does shivering regulate temperature?

Answer 13

• muscles relax & contract
• increases respiration
• more heat energy is released
• increases temperature

Question 14

what are the two hypothalamus control centres?

Answer 14

heat loss and heat gain

Question 15

describe the heat loss centre

Answer 15

• activated when blood temp flowing through hypothalamus increases
• impulses are sent along an autonomic motor neurone to effectors
• response is triggered to lower core body temp

Question 16

describe the heat gain centre

Answer 16

• activated when blood temp flowing through hypothalamus decreases
• impulses are sent along an autonomic motor neurone to effectors
• response is triggered to raise core body temp

Question 17

give examples of endotherms

Answer 17

mammals, birds

Question 18

given examples of ectotherms

Answer 18

fish, amphibians, reptiles, invertebrates

Question 19

state 5 factors that affect organisms temperature

Answer 19

• exothermic chemical reactions
• latent heat of evaporation
• radiation
• convection
• conduction

Question 20

explain latent heat of evaporation

Answer 20

objects cool down as water evaporates from its surface

Question 21

explain radiation

Answer 21

the transmission of electromagnetic waves to and from the air, water or ground

Question 22

explain convection

Answer 22

heating and cooling by currents of air or water (warm rises, cold sinks)

Question 23

explain conduction

Answer 23

heating due to molecular collisions (best in water and ground)

Question 24

state 3 behavioural responses of ectotherms

Answer 24

• absorb radiation from sun
• conduction
• hide in shade / move into water or mud

Question 25

state 3 physiological responses of ectotherms

Answer 25

• dark coloured skin (absorbs more radiation)
• alter heart rate to regulate metabolic rate and affect warming/cooling
• require less food

Question 26

what is an ectotherm

Answer 26

an organism that uses its surroundings to warm its body - core body temp heavily reliant on environment

Question 27

what is an endotherm

Answer 27

an organism that relies of metabolic processes to warm their bodies - able to maintain stable core body temp regardless of environment temperature

Question 28

state 4 rapid responses for warming up

Answer 28

• vasoconstriction
• decreased sweating
• raising body hair or feathers
• shivering