Unit 3 - Temperature Control

Question 1

Where is the thermoregulatory centre and what does it do?

Answer 1

In the hypothalamus, it senses the temperature of the blood flowing through the hypothalamus

Question 2

How does the thermoregulatory centre recieve information?

Answer 2

Via sensory neurones from heat receptors in the skin

Question 3

When core body temperature rises what does the hypothalmus do?

Answer 3

It triggers responses which increase heat losses

Question 4

What happens when the blood flows through blood capillaries close to the surface of the skin?

Answer 4

Heat is lost to the surroundings

Question 5

Explain how vasodialation works

Answer 5

• If the core body temperature starts to rise, then the muscle in the arteriole walls relaxes and the arteriole dialates (gets wider)
• More blood then flows through the capillaries near the surface of the skin
• This increases the rate of heat loss from the body

Question 6

Explain why shivering happens

Answer 6

• Muscles require energy to contract, this energy is suppolied by respiration
• During respiration some energy is lost to the surrounding as heat energy
• When we shiver the muscles contract repeatedly so the rate of respiration in the muscles increases and more heat is generated

Question 7

Explain what happens when someone gets too cold

Answer 7

• Shivering - using muscle contractions to create heat
• Hair erection - traps an insulating layer of air
• Vasoconscription - blood flow decreases to the skin
• Behavioural - put on clothes
• Increase respiration

Question 8

Explain what happens to someone when they get too hot

Answer 8

• Sweating - evaporates and takes heat with it
• Panting (animals) - increases evaporation from the tongue
• Vasodialation - blood flow increases to the skin - heat travels in the blood which gets to limbs etc where its closer to the outsode
• Behavioural adaptations - drinking, go to shade

Question 9

What do the erector muscles do?

Answer 9

They contract to pull hair’s upright

Question 10

Q: What is hypothermia?

Answer 10

A syndrome caused when the body’s core it too cold

Question 11

Q: What is out of balance to create hypothermia?

Answer 11

Heat being generated vs heat loss

Question 12

Q:What 2 other factors have to be kept constant in the body via homeostasis?

Answer 12

• Sugar levels
• Bodys water content

Question 13

Q: What detects external temperatures in our bodies?

Answer 13

The brain

Question 14

Q: What is the job of the hypothalamus in terms of temperature regulation?

Answer 14

1. Detects temperature of blood in brain
2. Recieves information from receptors in the skin
3. Temperature too cold - activates systems that decrease heat loss and increases heat generation
4. Temperature too hot - opposite ^