Homeostasis

Question 1

What is homeostasis?

Answer 1

The maintenance of a constant internal environment.

Question 2

What are the 6 main things to be controlled in our bodies?

Answer 2

At just the right level:
-Body temperature.
-Water content.
-Ion content.
-Blood sugar levels.
Waste products:
-Carbon dioxide (product of respiration).
-Urea (excess amino acids).

Question 3

Why must body temperature be at just the right level?

Answer 3

It cant get too hot or too cold.

Question 4

Why must water content be at the just right level?

Answer 4

It can’t get too high or too low, as too much water could move into or out of cells and damage them.

Question 5

Why must ion content be at just the right level?

Answer 5

It can’t get too high or too low, as too much ions could move into or out of cells and damage them.

Question 6

Why must the blood sugar level be at just the right level?

Answer 6

It needs to stay within certain limits.

Question 7

What must happen to the waste product carbon dioxide?

Answer 7

It must be removed, as it is toxic in high quantities, it leaves the body by the lungs when you breathe out (it is a waste product of respiration).

Question 8

What must happen to the waste product urea?

Answer 8

It must be removed, as it is poisonous (it is a waste product from excess amino acids).

Question 9

Why must body temperature be carefully controlled?

Answer 9

Because all enzymes work the best at a certain temperature (human body enzymes work best at 37’c).

Question 10

What happens when the body gets too hot or cold?

Answer 10

The enzymes won’t work properly and really important reactions may be disrupted, even leading to death.

Question 11

What is in the brain that acts as your own personal thermostat?

Answer 11

The thermoregulatory centre.

Question 12

What does the thermoregulatory centre contain?

Answer 12

Receptors that are sensitive to the temperature of blood flowing through the brain.

Question 13

What happens when you are too hot?

Answer 13

• Your hairs lie flat.
• Sweat is produced by sweat glands and evaporates from the skin, which removes heat.
• The blood vessels supplying the skin dilate so more blood flows close to the surface of the skin, making it easier for heat to be transferred from the blood to the environment.

Question 15

What does the thermoregulatory centre receive?

Answer 15

Impulses from the skin giving information about skin temperature.

Question 15

What happens when you are too cold?

Answer 15

• Hairs stand up to trap an insulating layer of air.
• No sweat is produced.
• Blood vessels supplying skin capillaries constrict to close off the skins blood supply.
• When your cold you shiver (your muscles contract automatically), this needs respiration which releases some energy to warm the body.