KA4- Hypothalamus

Question 1

Where is the hypothalamus?

Answer 1

In the brain

Question 2

What is the hypothalamus?

Answer 2

The body’s temperature monitoring centre

Question 3

What does the hypothalamus act as?

Answer 3

A thermostat

Question 4

How does the hypothalamus receive nerve impulses?

Answer 4

Through thermoreceptors in the skin

Question 5

What does the hypothalamus also contain?

Answer 5

Internal thermoreceptors

Question 6

What do these internal thermoreceptors detect?

Answer 6

Change in the blood temperature

Question 7

How does the thermoregulatory centre respond to changes?

Answer 7

By sending nerve impulses out to various effectors

Question 8

Where is the thermoregulatory centre?

Answer 8

In the hypothalamus

Question 9

What does the skin act as?

Answer 9

An effector

Question 10

What does the skin respond to?

Answer 10

Nerve impulses from the hypothalamus

Question 11

What is vasoconstriction?

Answer 11

Arterioles leading to the skin become constructed, reducing blood flow to the surface and less heat is lost by radiation

Question 12

What is vasodilation?

Answer 12

Skin arterioles dilate, which allows a large volume of blood into the skin capillaries and causes more heat to be lost by radiation

Question 13

What loses more heat; vasodilation or vasoconstriction?

Answer 13

Vasoconstriction

Question 14

What does every hair have?

Answer 14

Its own erector muscle

Question 15

What happens to the erector muscle in cold conditions?

Answer 15

Muscle contracts, raising hairs from the skin’s surface and trapping a layer of air around the body

Question 16

Why does the erector muscle act as an insulator?

Answer 16

As the muscle contracts, the raised hairs from the skin’ surface trap a layer of air around the body

Question 17

When is sweat released?

Answer 17

In very hot conditions

Question 18

Where is sweat released?

Answer 18

Onto the surface of the skin

Question 19

What releases sweat?

Answer 19

Sweat glands

Question 20

When do sweat glands not produce heat?

Answer 20

In cold conditions

Question 21

How does shivering generate heat?

Answer 21

By rapid skeletal muscle contractions causing friction between the muscle fibres

Question 22

When do we shiver?

Answer 22

In very cold conditions

Question 23

When does MR increase?

Answer 23

In cold conditions

Question 24

When does MR decrease?

Answer 24

In hot conditions

Question 25

Why does MR increase in cold conditions?

Answer 25

As it generates more heat

Question 26

Why does MR decrease in hot conditions?

Answer 26

As it generates less heat