2.5 The Brain & The Eye Flashcards
What is the brain made of?
The brain is made of billions of interconnected neurones
What is the function of the brain?
The function of the brain is to control complex behaviour
What are the 6 regions of the brain?
- Cerebral Cortex
- Cerebellum
- Medulla
- Spinal Chord
- Pituitary Gland
- Hypothalamus
What is the Cerebral Cortex responsible for?
The Cerebral Cortex controls language, memory, intelligence and consciousness
What is the Cerebellum responsible for?
The Cerebellum is responsible for muscle coordination, balance and movement
What is the Medulla responsible for?
The Medulla is responsible for unconscious activities such as breathing and heart rate
Why is difficult to investigate and study brain function?
Because the brain is an incredibly complex and very delicate organ
- Also because it is inside the skull
How have neuroscientists been able to research and map out parts of the brain?
- By studying people with brain damage to see which functions have been affected
- By electrically stimulating parts of the brain to observe any visible responses and also see the effects of it
- By using MRI Scanning Techniques to help highlight areas of the brain that are active during different activities
Explain the Eye
The eye is a sense organ which contains receptors that are sensitive to light intensity and colour
What is the Iris?
The iris is a thin layer in front of the lens
It contains muscle cells which contract to control the size of the pupil
What is the Pupil?
The pupil is a hole that allows light to enter the eye
What are Ciliary Muscles?
Ciliary muscles are rings of muscles that change the shape of the lens to focus light rays on the back of the retina
What are Suspensory Ligaments?
Suspensory Ligaments are strong radial ligaments that hold the lens in the centre of the right of the ciliary muscle
What is the retina?
The retina is a layer containing receptors sensitive to the light intensity and light colour
What are the two types of receptor cells in the eye?
What are they responsible for?
- Rod Cells which detect light intensity
- Cone Cells which detect colour
What is the function of the optic nerve?
The optic nerve contains neurones that carry impulses from the receptor cells in the retina to the brain, and from the brain to the muscles in the eye
What is the sclera?
The sclera is the white, protective outer layer of the eye that protects the eye and maintains the shape of the eye
What is the cornea?
The cornea is a transparent part of the sclera which allows light through eye and refracts it as it enters the eye to focus on the retina
What is the function of the lens?
The lens refracts rays of light so that they focus at the retina
What features allow the lens to perform its function?
The lens is elastic, so it is able to change shape when the suspensory ligaments attached to it become tighter or looser.
What is accommodation?
Accommodation is the process of changing the shape of the lens so that they focus on near or distant objects
How does the eye focus on a near object?
The ciliary muscles contract whilst the suspensory ligaments loosen, causing the lens to be thicker and light to be refracted strongly
How does the eye focus on a distant object?
The ciliary muscles relax whilst the suspensory muscles are pulled tight, causing the lens to be pulled thin and refract light lightly
What is adaptation?
Adaptation is a reflex action that protects the retina from damage in bright light and protects us from not seeing objects in dim light
What happens to the iris in bright light?
In terms of adaptation
In bright light, the circular muscles of the iris contract to narrow the size of the pupil - to prevent too much light from entering
What happens to the iris in dim light?
In dim light, the radial muscles of the iris contract to dilate the pupils and allow as much light as possible into the eye
What are the 2 defects of the eyes?
+ How do they happen?
Myopia (Short-Sightedness)
Hyperopia (Long-sightedness)
They happen when the rays of light do not focus on the retina
How are myopia and hyperopia generally treated?
Myopia and Hyperopia are generally treated with spectacle lenses that refract rays of light so that they focus on the retina
- Myopia is generally treated with concave lenses
- Hyperopia is generally treated with convex lenses
What type of new technologies can also treat eye defects?
- Soft and hard contact lenses
- Laser surgery that changes the shape of the cornea
- A replacement lens in the eye
