Homeostasis

Question 1

What is homeostasis?

Answer 1

The process of maintaining a constant internal environment

Question 2

Give an example of four bodily levels that need to be controlled?

Answer 2

• Ion content
• Water content
• temperature
• blood glucose level

Question 3

Give three ways in which water is lost from the body

Answer 3

• through the skin as sweat
• via the lungs in breath
• via the kidneys as urine

Question 4

What is the human body temperature?

Answer 4

37 degrees

Question 5

Why is it this temperature?

Answer 5

Because the enzymes in the human body work best at 37 degrees

Question 6

What foods contain glucose that we need?

Answer 6

Carbohydrates

Question 7

Where does deamination happen and what is it?

Answer 7

In the liver. The liver breaks down amino acids into ammonia this is because large amounts of amino acids can be damaging if they stay in the body.

Question 8

What is detoxification?

Answer 8

When the liver breaks down harmful substances into less harmful substances that are excreted in the urine

Question 9

What do the kidneys do?

Answer 9

They filter the blood to produce urine

Question 10

What are the 3 main things the kidneys do?

Answer 10

• Filter the blood
• Reabsorb products : all glucose, any dissolved ions and any water needed by the body
• Release urea, excess ions and excess water as urine

Question 11

What happens in ultrafiltration?

Answer 11

A high pressure is built up which squeezes out water,urea,ions and sugar out of the blood and into the Bowmans capsule. The membranes between the blood vessels and the bowmans capsule act like a filter, so big molecules like proteins and blood cells are not squeezed out.

Question 12

What happens in réabsorption?

Answer 12

• all the sugar is reabsorbed, via active transport
• sufficient ions are reabsorbed, via active transport
• sufficient water is reabsorbed

Question 13

What is the hormone that controls the amount of water reabsorbed called?

Answer 13

ADH - anti-diuretic hormone

Question 14

What part of the brain is instructed to release ADH into the body?

Answer 14

Pituitary gland

Question 15

What does the body do if the water content in the blood is too low?

Answer 15

ADH is released into the body, meaning more water is reabsorbed by the kidneys

Question 16

What does the body do if the water content in the blood is too high?

Answer 16

Less ADH is released, meaning less water is reabsorbed by the kidneys

Question 17

What does your body do to cool down?

Answer 17

• hairs lie flat
• sweating
• vasodilation

Question 18

What is vasodilation and how does it cool you down?

Answer 18

The blood vessels dilate so more blood flows closer to the surface of the skin. The vessels now have a larger surface area so more heat is lost to the environment by radiation

Question 19

What does you body do to warm up?

Answer 19

• Hairs stand up
• no sweat is produced
• vasoconstriction
• shivering

Question 20

What is vasoconstriction and how does it warm you up ?

Answer 20

The blood vessels shrink so there is a lower surface area so less heat is lost by radiation

Question 21

How does shivering keep you warm?

Answer 21

When your muscles contract automatically it requires respiration which releases some energy to warm the body

Question 22

How is glucose normally removed from the blood?

Answer 22

From the normal metabolism of cells

Question 23

What is excess glucose stored as?

Answer 23

It is stored a glycogen in the liver and in the muscles

Question 24

What is the glucose stored as when the stores are full?

Answer 24

It is stored as lipids in the tissues

Question 25

What controls the blood glucose levels?

Answer 25

The pancreas,using the hormones insulin and glucagon

Question 26

What does the body do if the blood glucose level is too high?

Answer 26

Insulin is secreted by the pancreas. Glucose is removed by the liver and other cells and tissues, insulin makes the liver turn glucose into glycogen.

Question 27

What does the body do if the blood glucose level is too low?

Answer 27

Glucagon is secreted by the pancreas. Glucose is added by the liver, glucagon makes the liver turn glycogen into glucose.

Question 28

What is type 1 diabetes?

Answer 28

When someone’s pancreas produces little or no insulin. This means the blood glucose level can rise to a level which can kill them.

Question 29

What is type 2 diabetes?

Answer 29

When someone’s body becomes resistant to their own insulin. This can cause their blood sugar level to rise to a dangerous level