Homeostasis

Question 1

Define ‘homeostasis’

Answer 1

All the functions in your body which try to maintain a ‘constant internal environment’

Question 2

Why must certain things be kept at the right level within your body?

Answer 2

To keep all your cells working properly

Question 3

Name 4 bodily levels that need to be controlled

Answer 3

1. Ion content
2. Sugar content
3. Water content
4. Temperature

Question 4

Which organs regulate ion content?

Answer 4

The kidneys

Question 5

Give an example of an ion

Answer 5

Sodium, Na⁺

Question 6

Ions are taken into the body in ____, then ____ into the ____ .

Answer 6

Ions are taken into the body in food, then absorbed into the blood.

Question 7

How do ions get into the body?

Answer 7

They are taken in in food

Question 8

What happens if food contains too much of an ion?

Answer 8

The excess ions need to be removed

Question 9

Give an example of food containing too much of an ion

Answer 9

A salty meal containing too much Na+

Question 10

Name 2 ways that excess ions are removed

Answer 10

1. Some are lost in sweat
2. The kideneys will remove excess from the blood - this is then gotten rid of in urine

Question 11

Eating what kind of food causes glucose to be put into the blood?

Answer 11

Carbohydrates

Question 12

Where does the glucose put into the blood come from?

Answer 12

The gut

Question 13

If you aren’t exercising, describe how glucose is removed from the blood

Answer 13

The normal metabolism of cells removes glucose from the blood

Question 14

What happens to how much glucose is removed from the blood when you do a lot of vigorous exercise?

Answer 14

Much more glucose is removed from the blood

Question 15

Which hormone helps to maintain the right levels of glucose in your blood?

Answer 15

Insulin

Question 16

Why does insulin need to help maintain the right level of glucose in your blood?

Answer 16

So your cells get a constant supply of energy

Question 17

There’s a need for the body to ____ ____ the water coming in against the water coming out

Answer 17

There’s a need for the body to constantly balance the water coming in against the water coming out

Question 18

Name the 2 ways water is taken into the body

Answer 18

1. As food
2. As drink

Question 19

Name the 3 main ways and the 4th ways that water is lost from the body

Answer 19

1. Through the skin as sweat
2. Via the lungs as breath
3. Via the kidneys as urine
   (4. Some is also lost in faeces)

Question 20

Name 2 things that the balance between sweat and urine can depend upon

Answer 20

1. How much exercise you’re doing
2. The weather

Question 21

Describe the balance of sweat and urine (+ urine detail) produced by the body on a cold day when you aren’t exercising much

Answer 21

You don’t sweat much

SO

You’ll produce more urine which will be pale

Question 22

Why does yor urine go pale when you don’t sweat much?

Answer 22

The water carried in the urine is more diluted

Question 23

Describe the balance of sweat and urine (+ urine detail) produced by the body on a hot day when you are exercising

Where else will you water?

Why

Answer 23

You sweat a lot

SO

You’ll produce less urine which will be a deeper colour

You will also lose more water through your breath

Because when you exercise you breathe faster

Question 24

Why will your urine ne a deeper colour on a hot day when you’re exercising?

Answer 24

Because you will lose more water in your sweat and your breath so your urine will be more concentrated

Question 25

Which organ controls body temperature?

Answer 25

The **brain**

Question 26

What temperature does the body try to maintain?

Answer 26

37^oC

Question 27

Why does your body try to maintain a constant temperature of **37^oC**?

Answer 27

Because that is the temperature that the **enzymes** within the human body _work best at_

Question 28

Explain how your brain works in terms of keeping yor body at a constant temperature (2)

Answer 28

1. A _part_ of the brain is **sensitive** to the **blood temperature** in the _brain_ 2. It receives **messages** from the **skin** that provide _information_ about **skin temperature**

Question 29

Which 2 substances do sports drinks often include?

Answer 29

1. Electrolytes 2. Carbohydrates

Question 30

Why do sports drinks often contain electrolytes?

Answer 30

To **replace** the **salts** lost in **sweat**

Question 31

Why do sports drinks often contain carbohydrates?

Answer 31

To give you an _energy boost_ (more **glucose** in blood to be used in **respiration** be your **cells**)