The kidneys and homeostasis

Question 1

What are the kidneys three main roles?

Answer 1

• The removal of urea from the blood.
• Adjustment of ions in the blood.
• Adjustment of water content of the blood.

Question 2

Protein can’t be stored in the body, what are any excess amino acids converted into?

Answer 2

Fats and carbohydrates in the liver which can be stored.

Question 3

What is produced when excess amino acids are converted into fats and carbohydrates in the liver?

Answer 3

The reaction produces poisonous urea which is a waste product from the reactions.

Question 4

How is urea removed?

Answer 4

It is released into the bloodstream by the liver, and is then filtered out of the blood by the kidneys, and temporarily stored in the bladder before it is excreted from the body in urine.

Question 5

How do we get ions such as sodium?

Answer 5

They are taken into the body in food and then absorbed Into the blood.

Question 6

What can upset the balance between ions and water?

Answer 6

If the ion or water content is wrong.

Question 7

What happens when the ion or water content is wrong in our bodies?

Answer 7

Too much or too little water is drawn into cells by osmosis, having the wrong amount of water can damage cells or mean they don’t work as well as normal.

Question 8

How are excess ions removed?

Answer 8

By the kidneys (e.g. a salty meal will contain too much sodium, so excess sodium ions are removed from the blood by the kidneys).

Question 9

What other ways are ions lost?

Answer 9

Through sweat.

Question 10

How is the balance between water and ion content maintained?

Answer 10

By the kidneys.

Question 11

How is water lost from the body?

Answer 11

• In urine.
• In sweat.
• In the air we breath out.

Question 12

How does the body maintain a constant balance of water coming in against water coming out?

Answer 12

The balance is between:

• Liquids consumed.
• Amount sweated out.
• Amount excreted by the kidneys in the urine.

Question 13

What happens to urine on a cold day?

Answer 13

If you don’t sweat, you will produce more urine which will be pale and dilute.

Question 14

What happens to urine on a hot day?

Answer 14

You sweat a lot, and you will produce less urine which will be dark coloured and concentrated.

Question 15

How is balance of water restored on a hot day?

Answer 15

The water lost has to be replaced with water from food and drink to restore balance.

Question 16

What do sports drinks replace?

Answer 16

• Water.
• Sugar.
• Ions.

Question 17

What does the water and ions contained by a sports drink replace?

Answer 17

The water and ions lost in sweat.

Question 18

What does the sugar contained by a sports drink replace?

Answer 18

The sugar that’s used up by muscles during exercise.

Question 19

What do some sports drinks manufacturers claim?

Answer 19

That their product will rehydrate you faster than plain water, or improve your endurance.

Question 20

How do you judge whether you can believe claims like some sports manufactures claims?

Answer 20

Think about if:

• The report is a scientific study.
• The report was published in a reputable journal.
• The report was written by a qualified person.
• The sample was large enough.
• Other studies have found the same results.