Thermoregulation

What is thermoregulation?

The maintenance of a relatively constant core body temperature

Why is thermoregulation important?

To maintain optimum enzyme activity

What are ectotherms?

Animals that use their surroundings to regulate body temperature

What are examples of ectotherms?

Reptiles and fish

How do ectotherms regulate body temperature?

Mainly through behavioural changes

How does environmental temperature affect ectotherms?

Their internal temperature is influenced by environmental temperature

How does environmental temperature affect ectotherm activity?

Activity increases when environmental temperature rises

What are endotherms?

Animals that use metabolic processes to control body temperature

What are examples of endotherms?

Mammals and birds

How do endotherms regulate body temperature?

Through internal processes and behavioural changes

How does environmental temperature affect endotherms?

Their internal temperature remains relatively stable

What happens when body temperature is too high?

Sweating increases hair flattens and vasodilation occurs

How does sweating reduce body temperature?

Evaporation of sweat causes cooling

What happens to hair when body temperature is too high?

It flattens to reduce insulation

What is vasodilation?

Widening of arterioles near the skin

How does vasodilation increase heat loss?

It increases blood flow to the skin

What happens when body temperature is too low?

Shivering vasoconstriction and hair erection occur

How does shivering increase body temperature?

Muscle contractions increase respiration and heat production

What happens to sweating when body temperature is too low?

Sweating decreases

What happens to hair when body temperature is too low?

It is raised to trap warm air

What is vasoconstriction?

Narrowing of arterioles near the skin

How does vasoconstriction reduce heat loss?

It reduces blood flow to the skin

Which hormones increase heat production?

Adrenaline and thyroxine

How do adrenaline and thyroxine increase body temperature?

They increase cellular metabolism and heat production

What is the role of the hypothalamus in thermoregulation?

It detects temperature changes and coordinates responses

Where does the hypothalamus get temperature information from?

Temperature receptors in the hypothalamus and skin

What are peripheral temperature receptors?

Temperature receptors in the skin

What happens when blood temperature increases?

The heat loss centre is stimulated

What does the heat loss centre do?

Sends impulses to effectors to increase heat loss

What happens when blood temperature decreases?

The heat gain centre is stimulated

What does the heat gain centre do?

Sends impulses to effectors to reduce heat loss

What are the two thermoregulatory centres in the hypothalamus?

Heat loss centre and heat gain centre