B3.3 - Homeostasis

Question 1

Where does the carbon dioxide in the body come from?

Answer 1

Respiration.

Question 2

Where does the urea in the body come from?

Answer 2

The breakdown of amino acids in the liver.

Question 3

How is carbon dioxide removed from the body?

Answer 3

Via the lungs when we breathe out.

Question 4

How is urea removed from the body?

Answer 4

By the kidneys via the urine.

Question 5

What will happen if the water and ion content of the body is wrong?

Answer 5

Too much water can move in/out of the cells, hence damaging them.

Question 6

When do water and ions enter our body?

Answer 6

When we eat and drink.

Question 7

How do kidneys produce urine? (5)

Answer 7

1. Filtering the blood.
2. Reabsorbing all the sugar.
3. Reabsorbing the dissolved ions that the body needs.
4. Reabsorbing as much water as the body needs.
5. Releasing urea, excess ions and water as urine.

Question 8

What is reabsorbed by the kidneys? (3)

Answer 8

1. Dissolved ions.
2. Water.
3. Sugar.

Question 9

What waste products must be removed from the body? (2)

Answer 9

1. Carbon dioxide.

2. Urea.

Question 10

What can be done if somebody has kidney failure? (2)

Answer 10

1. Dialysis.

2. A kidney transplant.

Question 11

What are the disadvantages of dialysis? (2)

Answer 11

1. It may cause blood clots/infections.

2. It has to be done around 3 times a week for 3-4 hours.

Question 12

What can be done to prevent donor kidneys from being rejected by the immune system? (2)

Answer 12

1. Donors with similar tissues to the patient are used.

2. Patients take immunosuppressant drugs so that their immune system doesn’t attack the transplanted kidney.

Question 13

What diffuses into the dialysis fluid?

Answer 13

Excess ions/water and waste products e.g. urea.

Question 14

The dialysis fluid has the same concentration of dissolved ions as ____ ____.

Answer 14

Healthy blood.

Question 15

In dialysis, the blood flows alongside a ____ ____ ____.

Answer 15

Partially permeable membrane.

Question 16

What are antigens and where are they on cells?

Answer 16

Proteins on the surface of cells.

Question 17

What can happen if the recipient of a kidney transplant’s immune system doesn’t recognise the antigens of the donor?

Answer 17

Their immune system will attack the antigens.

Question 18

What happens to the enzymes in the body is the temperature is extremely high or low?

Answer 18

They stop working properly and therefore disrupt reactions.

Question 19

What does sweating do?

Answer 19

Cool the body.

Question 20

What conditions cause a greater water loss?

Answer 20

High temperatures.

Question 21

What can be done to balance the water lost from sweat?

Answer 21

Eating and drinking.

Question 22

What is homeostasis?

Answer 22

The maintenance of a constant internal environment.

Question 23

Which part of the body monitors temperature?

Answer 23

The brain (the thermoregulatory gland).

Question 24

How does the brain measure the temperature? (2)

Answer 24

1. By monitoring the temperature of the blood flowing through the brain.
2. Receptors in the skin send impulses to the brain.

Question 25

What do blood vessels do when it is too hot and why?

Answer 25

They dilate so that more blood can flow through them and more heat can be lost.

Question 26

What do sweat glands do when it is hot and why?

Answer 26

Release more sweat, which cools the body as it evaporates and takes away body heat with it.

Question 27

What do hairs do when it is cold and why?

Answer 27

The hairs stand up in order to trap an insulating layer of air.

Question 28

Why do muscles shiver when you are cold?

Answer 28

Their contraction releases some energy from respiration that warms the body.

Question 29

What do blood vessels do when it is cold?

Answer 29

They constrict the flow of blood flow through capillaries.

Question 30

Which organ monitors blood glucose?

Answer 30

The pancreas.

Question 31

When is insulin produced?

Answer 31

When your blood sugar levels are too high.

Question 32

When is glucagon produced?

Answer 32

When your blood sugar levels are too low.

Question 33

What does insulin do?

Answer 33

Insulin makes the liver turn glucose into glycogen, and allows glucose to move from the blood and into the cells.

Question 34

What does glucagon do?

Answer 34

Glucagon makes the over turn glycogen into glucose, and then releases the glucose into the blood.

Question 35

What is Type 1 diabetes caused by?

Answer 35

The pancreas producing insufficient insulin levels.

Question 36

How can Type 1 diabetes be controlled? (3)

Answer 36

1. Avoiding food high in carbohydrates.
2. Exercise.
3. Injecting insulin.