Nervous system and homeostasis B Flashcards
What are the different parts of the human eye?
- Iris
- Ciliary muscles
- Suspensory ligaments
- Retina
- Pupil
- cornea
- Optic nerve
- Lens
What does the Ciliary muscle do?
Contracts and relaxes to change the shape of the lens.
What does the Retina do?
Layer of light receptors at the back of the eye.
What does the Sclera do?
White layer that is tough to protect the eye.
What does the optic nerve do?
Nerve that connects the eye to the brain.
What does the suspensory ligaments do?
Tightens and slackens to change the shape of the lens.
What does the Lens do?
Sits behind the pupil and focuses light on the retina.
What does the Cornea do?
Transparent and curved letting light in and changing its direction to focus on the retina.
What does the Iris do?
Coloured part of the eye containing muscles that contract and relax changing the size of the pupil.
What is accomodation?
Changing of the shape of the lens to focus on near or distant objects.
What happens to Focus on a Distant object?
- Ciliary muscles contract
- Suspensory ligaments are slack
- Lens is thicker so it bends light more
What happens to focus on a near object?
- Ciliary muscles relax
- Suspensory ligaments are pulles tight
- Lens is thinner and flatter
What is myopia?
Short-sightedness, when distant objects look blurry because the rays are infront of the retina.
How is myopia treated?
Using concave spectacle lenses.
What is hyperopia?
Long sightedness, When near objects looked blurred because the rays are behind the retina.
