B10

Question 1

What is homeostasis?

Answer 1

The regulation of the internal conditions of a cell or organism to maintain optimum conditions for function in response to internal or external change.

Question 2

What does homeostasis control?

Answer 2

Body temperature, the water content in your body and the glucose concentration in your blood.

Question 3

What are the receptors?

Answer 3

Cells that detect changes in the internal or external environment(stimuli).

Question 4

What is a coordination centre?

Answer 4

Areas that receive and process the information from the receptors, sending signals to coordinate a response.

Question 5

What are effectors?

Answer 5

The muscles or glands that brig about responses to the stimulus that has been received.

Question 6

What is a nerve?

Answer 6

A bundle of neurones which are special cells that send electrical impulses.

Question 7

How does the nervous system work?

Answer 7

The impulse travels along until it reaches the CNS. It then moves to the sensory neurones where it gets lots of information. It is then passed to the motor neurone to carry information from the CNS to your body then the effectors respond.

Question 8

What are reflexes?

Answer 8

Automatic responses that help to make basic bodily functions work.

Question 9

What is a reflex arc?

Answer 9

It goes from the receptor, along the sensory neurones, through the relay neurone and along the motor neurone. Then it arrives at the effector organ through the reflex arc.

Question 10

How do synapses work?

Answer 10

There is a diffusion of a chemical across the synapse which causes the next neurone to set up a new electrical impulse.

Question 11

What is the cerebral cortex?

Answer 11

Concerned with consciousness, intelligence, memory and language.

Question 12

What is the cerebellum?

Answer 12

It coordinates muscular activity and balance.

Question 13

What is the medulla?

Answer 13

Concerned with unconscious activities such as controlling the heart beat.

Question 14

How can scientists study brain damage?

Answer 14

They can use MRI scans, or electrically stimulate different areas of the brain by mapping the different functions.

Question 15

What is the eye?

Answer 15

A sense organ containing many receptors that are sensitive to light intensity and colour. The cells are arranged in the back of the eye known as the retina.

Question 16

What is the sclera?

Answer 16

The tough white outer layer of the eye which has a transparent area at the front of the eyeball called the cornea, letting light into the eye and as it is curved it means the light will always be focused on the retina.

Question 17

What does the iris do?

Answer 17

It is the hole where light entered and is made of muscles to contract or relax to change the size of the pupil to control the amount of light reaching the retina so the cells are not damaged.

Question 18

Where is the lens held?

Answer 18

They are held by suspensory ligaments and the ciliary muscles, changing the direction of the lens to produce a clear image.

Question 19

How does the eye produce an image?

Answer 19

When the light hits the retina, light-sensitive cells are stimulated, sending impulses to the brain along sensory neurones in the optic nerve.

Question 20

How would you focus on a distant image?

Answer 20

You would relax the ciliary muscles so the suspensory ligaments are pulled tight and the lens is pulled flat and thin. It only refracts light rays slightly so they are focused on the retina.

Question 21

How would you focus on a near image?

Answer 21

The ciliary muscles contract so the suspensory ligaments loosen. The lens is then thicker and more curved. It refracts light rays strongly so they are focused on the retina.

Question 22

What is Myopia?

Answer 22

It is when you can see close objects in clear focus, but distant objects look blurred. The light is focused in front of the retina, as a result of a lens that is too curved or a particularly long eyeball.

Question 23

What is Hyperopia?

Answer 23

When you can focus clearly on distant objects but close objects appear blurred. This may be a result of a lens that is too flat and thin or of a particularly short eyeball. As a result, the lens cannot refract the light strongly enough.

Question 24

What are contact lenses?

Answer 24

They are lenses doing the same job as glasses.

Question 25

What is laser eye surgery?

Answer 25

It is used to treat myopia by reducing the thickness of the cornea so it refracts the light less strongly. It also treats hyperopia where it changes the curve of the cornea so it refracts light from close object more effectively.

Question 26

What are replacement lenses?

Answer 26

Putting another lens inside the eye to correct the visual defect permanently. This can be done by implanting a contact lens into the eye and the natural lens being left or the faulty lens being replaced by an artificial lens.