IGCSE Biology 9 Views 1 Answers
Identify in diagrams and images the structures of the eye, limited to: cornea, iris, pupil, lens, retina, optic nerve and blind spot
Identify in diagrams and images the structures of the eye, limited to: cornea, iris, pupil, lens, retina, optic nerve and blind spot
Answered step-by-step
The structures of the eye, including the cornea, iris, pupil, lens, retina, optic nerve, and blind spot, play crucial roles in vision. Below is a description of each structure along with a diagrammatic representation.
Structures of the Eye
1. Cornea
- Description: The cornea is the clear, dome-shaped front surface of the eye. It serves as a protective barrier and helps focus light onto the retina.
2. Iris
- Description: The iris is the colored part of the eye surrounding the pupil. It controls the size of the pupil and thus regulates the amount of light entering the eye.
3. Pupil
- Description: The pupil is the dark circular opening in the center of the iris. Its size changes in response to light levels—dilating in low light and constricting in bright light.
4. Lens
- Description: Located behind the iris and pupil, the lens is a transparent structure that further focuses light onto the retina. It can change shape (accommodate) to focus on objects at varying distances.
5. Retina
- Description: The retina is a thin layer of tissue lining the back of the eye. It contains photoreceptors (rods and cones) that convert light into electrical signals sent to the brain.
6. Optic Nerve
- Description: The optic nerve transmits visual information from the retina to the brain. It consists of millions of nerve fibers that carry electrical impulses.
7. Blind Spot
- Description: The blind spot is an area on the retina where there are no photoreceptors because it is where the optic nerve exits the eye. This results in a lack of visual information from that part of the visual field.
Did this page help you?