B3 - Homeostasis

Question 1

What are the 6 things that need to be controlled?

Answer 1

Body temperature
Water content
Ion content
Blood sugar
Carbon dioxide
Urea

Question 2

Why does the body keep body temperature at 37 degrees?

Answer 2

It is the optimum temperature for enzymes

Question 3

How is the body temperature measured by the brain?

Answer 3

The thermoregulartory centre in the brain has receptors that are sensitive to the temperature of the blood that is passing by it

Question 4

What 3 things happen when the body is too hot?

Answer 4

Hairs lie flat

Sweat is produced by sweat glands and is evaporated from the skin

Blood vessels dilate so that the blood flows closer to the surface of the skin

Question 5

What 3 things happen when the body is too cold?

Answer 5

Hairs stand up to form an insulating layer of air

No sweat is produced

Blood vessels constrict so that the blood is further from the surface

Question 6

What is homeostasis?

Answer 6

The maintenance of a constant internal environment

Question 7

What 3 things do kidneys do?

Answer 7

Remove urea from the blood

Adjust ions in the blood

Adjust water content in the blood

Question 8

Describe the journey of urea in the body

Answer 8

It is produced by the liver as a waste product

It is released into the blood by the liver

The kidneys filter it out of the blood and it is stored as urine in the bladder and it is excreted

Question 9

How do the kidneys adjust the ion content?

Answer 9

Excess ions that would upset the balance of the ions and water are removed by the kidneys and added to the urine to be excreted

Question 10

What is the other way that ions can be removed from the body?

Answer 10

In sweat

Question 11

What are the 3 ways that water is lost from the body?

Answer 11

Urine
Sweat
Breathed out air

Question 12

In which 3 ways is the amount of water regulated?

Answer 12

Liquids consumed

Amount sweated out

Amount excreted by the kidneys into the urine

Question 13

If someone sweats a lot, how will their urine be different?

Answer 13

Less urine will be produced but it will be more concentrated

This is because there is less water available that can make it more dilute

Question 14

What are the 3 important substances that sports drinks contain and why?

Answer 14

Water and ions replace those lost in sweat

Sugar can be used in respiration to give the body more energy

Question 15

What are the 2 hormones that control blood sugar?

Answer 15

Insulin

Glucagon

Question 16

When is insulin used?

Answer 16

When blood glucose level is too high

Question 17

Describe the journey of insulin and how it works

Answer 17

It is secreted by the pancreas and travels with the blood until it reaches the liver

It causes the liver to turn glucose into glycogen causing blood sugar to decrease

Question 18

When is glucagon used?

Answer 18

When the blood glucose level is too low

Question 19

Describe the journey of glucagon and how it works

Answer 19

It is secreted by the pancreas and travels with the blood to the liver

It makes the liver turn glycogen into glucose meaning that the blood glucose level is increased

Question 20

What is type 1 diabetes?

Answer 20

A condition where the pancreas produces little or no insulin meaning the blood sugar level is too high

Question 21

What are the 3 simple ways of controlling type 1 diabetes?

Answer 21

Eating less simple carbohydrates

Regular exercise

Injecting insulin (insulin therapy)

Question 22

What are the old and new ways of getting insulin for patients?

Answer 22

The old way was to extract it from the pancreases of pigs and cows

The new way is to make human insulin with genetic engineering

Question 23

Give 2 reasons that the new method of getting insulin is better

Answer 23

Human insulin does not have any side-effects where animal insulin does

No animals are killed in the new method

Question 24

What is the more difficult way of removing type 1 diabetes?

Answer 24

A kidney transplant

Question 25

What is done if a transplant is rejected?

Answer 25

Immunosuppresive drugs are taken which are expensive and can have serious side-effects

Question 26

Why can’t insulin be taken in a pill?

Answer 26

The enzymes in the stomach would destroy it before it could reach the bloodstream