The brain + THE EYE

Question 1

Purpose of the brain

Answer 1

The brain controls complex behaviour (e.g. language)

Question 2

What is the brain made up of

The brain controls complex behaviour (e.g. language)
how does the brain do this

Answer 2

It is made of billions of
interconnected neurones and has different regions that carry out
different functions.

Question 3

parts of the brain

Answer 3

cerebral cortex
medulla
cerebellum

Question 4

Purpose of cerebral cortex

Answer 4

The highly folded, outer part of the brain
It is responsible for/its functions include language, intelligence, memory and consciousness

Question 5

Purpose of the cerebellum

Answer 5

The cerebellum controls our balance and coordinates our movements (muscle coordination)

Question 6

purpose of the medulla

Answer 6

The medulla controls unconscious activities for example heart rate and breathing rate

Question 7

label parts of the brain
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Answer 7

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Question 8

Describe how methods/ways scientists use to investigate brain function

Answer 8

1. Many scientists look at patients who have suffered brain damage

By looking to see where the damage has taken place, they can try to link that part of the brain to its function

2. Different parts of the brain can be electrically stimulated and look at the effects on the person behaviour
   That allows us to narrow down specific regions to their functions
3. MRI scanning can be used to look at which parts of the brain are most active during different activities
   E.g. when a person is looking at images, we see greater activity in the part of the brain responsible for image processing, we see greater activity in the part of the brain responsible for image processing

spec
Neuroscientists have been able to map the regions of the
brain to particular functions by studying patients with brain damage,
electrically stimulating different parts of the brain and using MRI
scanning techniques

Question 9

explain some of the difficulties of
investigating brain function and treating brain damage and disease

Answer 9

studying the brain is extremely difficult
It is also difficult to treat brain damage or brain diseases

The brain is protected by the skull so it is very tricky to access

The structures of the brain are extremely complex. So it is difficult to work out exactly which parts of the brain carry out specific functions

The brain is extremely delicate and easy to damage

_
spec The complexity and delicacy of the brain makes
investigating and treating brain disorders very difficult

Question 10

What is the eye

Answer 10

The eye is a sense organ containing receptors sensitive to light intensity and colour (of light)

Question 11

Name different parts of the eye

Answer 11

Pupil
retina
* optic nerve
* sclera
* cornea
* iris
* ciliary muscles
* suspensory ligaments.

Question 12

Label diffrerent parts of the eye
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Answer 12

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Question 13

What is the function of the cornea

Answer 13

The cornea is the transparent outer layer found at the front of the eye

Purpose: To refract light rays as they enter the eye
(to start the focussing of the light rays)

cornea: transparent area at front of eyeball that admits light, curved surface to help
focus light coming into the eye on retina;

Question 14

What is the function of the iris

Answer 14

The iris is the coloured part of the eye
The function of the iris is to control the size of the pupil and therefore how much light enters the eye (the iris contains muscles that allow it to control the diameter of the pupil - and therefore how much light enters the eye

Question 15

how does the iris control the size of the pupil (and how much light enters the eye)

Answer 15

(the iris contains muscles that allow it to control the diameter of the pupil - and therefore how much light enters the eye

Question 16

Function of the lens

Answer 16

The function of the lens is to focus the light rays onto the back of the eye
(allows us to focus on near or distant objects)

Question 17

Describe one key feature of the lens

Answer 17

One key feature of the les is that it can change shape, allowing it to focus on distant or near objects. This is called accommodation

Question 18

Describe the function of the retina

Answer 18

The back of the eye is called the retina
Contains receptor cells for light. These receptor cells allow us to detect light intensity and light colour (receptor cells sensitive to light intensity and colour)

Question 19

Describe the function of the optic nerve

Answer 19

Carries impulses from the receptors on the retina to the brain

Question 20

Describe how the eye works - describe how the eye detects light

Answer 20

Light rays pass through the transparent front of the eye - called the cornea
The function of the cornea is to refract light rays as they enter the eye
(to start the focussing of the light rays)

The light rays pass through the pupil in the centre of the iris

The iris is the coloured part of the eye

Light rays now pass through the lens. The function of the lens is to focus the light rays onto the back of the eye

Lens changes shape to focus light onto retina
The shape of the lens is controlled by the ciliary muscles and suspensory ligaments

One key feature of the lens is that it can its change shape, allowing the eye to focus on distance or near objects. This is called accommodation

The light rays are now focussed onto the back of the eye. This is called the retina.
The retina contains receptor cells for light
These receptor cells allow us to detect light intensity and light colour (receptor cells sensitive to light intensity and colour)

The receptor cells in the retina now send electrical impulses down the optic nerve to the brain

Question 21

What is the sclera and its function

Answer 21

The white part of the eye is called the sclera
This tough outer structure protects the eye

Question 22

What is the shape of the lens controlled by

Answer 22

The shape of the lens is controlled by the ciliary muscles and suspensory ligaments

Question 23

What two parts work with the lens

Answer 23

The ciliary muscles and the suspensory ligaments work with the lens

Question 24

What do the ciliary muscles and suspensory ligaments allow the eye to do

Answer 24

Together the ciliary muscles and the suspensory ligaments allow the eye to focus on distant or near objects

Question 25

What is the pupil

Answer 25

The pupil is the space in the centre of the iris which light passes through. The pupil allows light rays into the eye

Question 26

Explain how the eye adapts to dim light

Answer 26

If you enter a dark room, the amount of light entering the eye is now low This drop in light intensity is sensed by light receptors in the retina and these send electrical impulses to the brain The brain then sends electrical impulses to specific muscles in the iris. These muscles contract, causing the pupil to become larger This now allows more light to enter the eye This is a reflex action because it does not involve the conscious part of the brain ______________ pupils dilated in dim light because circular muscles (in iris) relax (and) radial muscles contract This now allows more light to enter the eye (pupils are wider

Question 27

Explain how the eye adapts to bright light

Answer 27

We can see the opposite effect if we walk into a bright room. In this case, the reflex causes the pupil to become smaller. This now reduces the amount of light entering the eye and protects it from damage (very bright light can damage the retina) _______________ If you enter a bright room, the amount of light entering the eye is now hight This increase in light intensity is sensed by light receptors in the retina and these send electrical impulses to the brain The brain then sends electrical impulses to specific muscles in the iris. These muscles relax, causing the pupil to become smaller This now allows less light to enter the eye In this case, the reflex causes the pupil to become smaller. This now reduces the amount of light entering the eye and protects it from damage (very bright light can damage the retina) This is a reflex action because it does not involve the conscious part of the brain __________ pupils constrict in bright light because circular muscles (in iris) constrict (and) radial muscles relax this now allows less light to enter the eye (pupils are smaller)

Question 28

Explain why this change of shape of pupils depending on differing conditions is a reflex action

Answer 28

This is a reflex action because it does not involve the conscious part of the brain

Question 29

What is a lot of the focussing carried out by

Answer 29

A lot of the focussing is carried out by the cornea (but the cornea is a fixed focus)

Question 30

What is the rest of the focussing carried out by

Answer 30

The rest of the focussing is carried out by the lens

Question 31

How does the lens allow us to focus on near and distant objects

Answer 31

The shape of the lens can change to allow us to focus on near and distant objects

Question 32

What is accommodation

Answer 32

The ability to change the shape of the lens to focus on near or distant objects

Question 33

What is the lens surrounded by - how is this structure connected to the lens

Answer 33

The lens is surrounded by a circular muscle called the ciliary muscle This is connected to the lens by fibres which are called suspensory ligaments

Question 34

How can the ciliary muscle change the thickness of the lens

Answer 34

By contracting or relaxing, the ciliary muscle can change the thickness of the lens

Question 35

What happens when the ciliary muscle contracts

Answer 35

When the ciliary muscle contracts, the suspensory ligaments loosen (relax) The lens is now thicker and refracts light rays more strongly

Question 36

What happens when the ciliary muscle relaxes

Answer 36

When the ciliary muscle relaxes, the suspensory ligaments are pulled tight (contract) The lens is now pulled thin and only slightly refracts light rays

Question 37

Explain how the eye accommodates to focus on distant objects

Answer 37

Light from distant objects needs to be focussed only a relatively small amount When the ciliary muscle relaxes, the suspensory ligaments are pulled tight (contract) The lens is now pulled thin Because the lens is thin, the light rays are only slightly reflected The light rays are now focussed to a point on the retina

Question 38

Explain how the eye accommodates to focus on near objects

Answer 38

Light from near objects need to be focussed a large amount When the ciliary muscle contracts, this causes the suspensory ligaments loosen (relax) The lens is now thicker and refracts light rays more strongly The light rays are now focussed to a point on the retina

Question 39

What does it mean when a person is short-sighted or longsighted

Answer 39

In these people the light rays do not focus correctly on the retina

Question 40

Describe what longsightedness is and how it can be caused

Answer 40

Long sightedness is also called hyperopia People with long sightedness have no problem at all focussing on distant objects but they cannot focus on nearby objects In many cases of longsightedness the eye ball is too short so the light is focused at a point behind the retina However in some cases, especially in the elderly, the lens becomes less elastic. In this case, the lens cannot become thick enough to focus on near objects

Question 41

Describe how long sightedness are treated

Answer 41

Long sightedness can be treated by using glasses with a convex lens These partially focus the light before it enters the eye This leads to the light rays now being able to focus to a point on the retina

Question 42

Draw the diagram for people with long sightedness Draw the diagram with people with glasses to treat long sightedness to illustrate how they work

Answer 42

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Question 43

Describe what short sightedness is

Answer 43

Short sightedness is also called myopia People with short sight can focus on nearby objects but they cannot focus on distant objects In people with short sight, the eyeball can be too long, so the light is focused at a point in front of the retina Short sightedness can also be caused when the lens is too thick The light is focussed in front of the retina

Question 44

How can short sightedness be treated

Answer 44

Short sightedness can be treated using glasses with concave lenses to partially unfocus the light before it enters the eye

Question 45

Draw the diagram for people with short sightedness Draw the diagram with people with glasses to treat short sightedness to illustrate how they work

Answer 45

https://bam.files.bbci.co.uk/bam/live/content/zs4g7p3/small https://bam.files.bbci.co.uk/bam/live/content/z82jsrd/small

Question 46

Alternatives to using glasses

Answer 46

People can also use hard or soft contact lenses These lenses sit on the eyeball and they refract light in the same way as glasses laser surgery can be used to change the shape of the cornea (so it refracts the light to a greater or lesser extent) a replacement lens in the eye (using an artificial lens)