B5: Homeostasis

Question 1

Give a definition of homeostasis.

Answer 1

Keeping a constant/stable internal environment.

Question 2

Give the four things the body needs to control.

Answer 2

Sugars
Salt
Temperature
Water

Question 3

Explain the function of the kidneys.

Answer 3

The kidneys respond to higher levels of water in the blood plasma, making more urine. They also remove waste material for the blood stream.

Question 4

Explain the function of the hypothalamus.

Answer 4

Controls the conditions like body temperature and CO2 levels.

Question 5

Explain the function of the lungs

Answer 5

Regulates temperature by passing hot/cold air in/out of the body. Also reduces CO2 levels with the brain.

Question 6

Explain the function of the skin.

Answer 6

Controls blood vessels in skin layer to cools blood down or lose heat.

Sweat glands put water onto skin (sweat), cooling down by evaporation.

Controls hairs on arms to trap air close to body.

Question 7

What does the pancreas do?

Answer 7

Produces insulin to convert excess glucose to glycogen. Produces glucagon to change glycogen back to glucose.

Question 8

What does the liver do?

Answer 8

Storage place for glycogen. Glycogen reconverts to glucose by glucagon from pancreas.

Question 9

What are the three main components that allow your body to automatically regulate itself?

Answer 9

Receptors
Effectors
Coordination centres

Question 10

What is a receptor?

Answer 10

Cells which detect stimuli (changes to the environment).

Question 11

What is an effective?

Answer 11

Muscles or glands which bring about responses to restore optimum conditions.

Question 12

What is a coordination centre?

Give som examples.

Answer 12

Receive and process information from receptors.

Eg. pancreas, brain, spinal cord

Question 13

What is a negative feedback loop?

Answer 13

A reaction that causes a decrease in function. Occurs in response to some kinds of stimuli.

Question 14

Why do we need a constant internal environment?

Answer 14

Cells need the right conditions to function. (Eg. Enzyme activity)

Question 15

Explain how negative feedback counteracts change.

Answer 15

1) receptor detects a stimulus - level is too high.
2) coordination centre receives and processes the information, then organised a response.
3) effector produces a response, which counteracts the change and restores the optimum level - the level decreases.

Question 16

Explain the response to stimuli.

Answer 16

1) receptor detects a stimulus - level is too low.
2) coordination centre receives and processes the information, then organises a response.
3) effector produces a response, which counteracts the change and restores the optimum level - the level increases.