1.Ciliary muscle:
2.Crystalline lens:
3. Iris :
4. Retina:
5. Blind spot. pls define
Answers
Answer:
Ciliary muscle
Ciliary muscle: A circular muscle that relaxes or tightens the zonules to enable the lens to change shape for focusing. The zonules are fibers that hold the lens suspended in position and enable it to change shape during accommodation.
Explanation:
Crystalline lens
The crystalline lens is the name given to the natural lens that humans are born with. Small muscles attached to the lens can make the lens change shape, which allows the eyes to focus on near or far objects.
Iris
In humans and most mammals and birds, the iris (plural: irides or irises) is a thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil and thus the amount of light reaching the retina. Eye color is defined by that of the iris.
Retina
a layer at the back of the eyeball that contains cells sensitive to light, which trigger nerve impulses that pass via the optic nerve to the brain, where a visual image is formed.
Blind Spot
Blind spot, small portion of the visual field of each eye that corresponds to the position of the optic disk (also known as the optic nerve head) within the retina. There are no photoreceptors (i.e., rods or cones) in the optic disk.