B5: Homeostasis Flashcards Preview

GCSE (TRILOGY) BIOLOGY (PAPER 2) > B5: Homeostasis > Flashcards

Flashcards in B5: Homeostasis Deck (16):
1

Give a definition of homeostasis.

Keeping a constant/stable internal environment.

2

Give the four things the body needs to control.

Sugars
Salt
Temperature
Water

3

Explain the function of the kidneys.

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

4

Explain the function of the hypothalamus.

Controls the conditions like body temperature and CO2 levels.

5

Explain the function of the lungs

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

6

Explain the function of the skin.

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.

7

What does the pancreas do?

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

8

What does the liver do?

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

9

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

Receptors
Effectors
Coordination centres

10

What is a receptor?

Cells which detect stimuli (changes to the environment).

11

What is an effective?

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

12

What is a coordination centre?

Give som examples.

Receive and process information from receptors.

Eg. pancreas, brain, spinal cord

13

What is a negative feedback loop?

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

14

Why do we need a constant internal environment?

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

15

Explain how negative feedback counteracts change.

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.

16

Explain the response to stimuli.

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.