Question

44.Explain the major parts of the human eye with a suitable diagram.​

Answer 1

Answer:

Sclera: It is the outer covering, a protective tough white layer called the sclera (white part of the eye).

Cornea: The front transparent part of the sclera is called cornea. Light enters the eye through the cornea.

Iris: A dark muscular tissue and ring-like structure behind the cornea are known as the iris. The colour of the iris actually indicates the colour of the eye. The iris also helps regulate or adjust exposure by adjusting the iris.

Pupil: A small opening in the iris is known as a pupil. Its size is controlled by the help of iris. It controls the amount of light that enters the eye

.

Lens: Behind the pupil, there is a transparent structure called a lens. By the action of ciliary muscles, it changes its shape to focus light on the retina. It becomes thinner to focus distant objects and becomes thicker to focus nearby objects.

Retina: It is a light-sensitive layer that consists of numerous nerve cells. It converts images formed by the lens into electrical impulses. These electrical impulses are then transmitted to the brain through optic nerves.

Optic nerves: Optic nerves are of two types. These include cones and rods.

Cones: Cones are the nerve cells that are more sensitive to bright light. They help in detailed central and colour vision.

Rods: Rods are the optic nerve cells that are more sensitive to dim lights. They help in peripheral vision

At the junction of the optic nerve and retina, there are no sensory nerve cells. So no vision is possible at that point and is known as a blind spot.

Answer 2

$\large \bf \red {Question:-}$

Explain the major parts of the human eye with a suitable diagram.

$\large \bf \red {Answer:-}$

The following are the parts of the human eye :-

• $\small \bf Pupil$ : The pupil is a small opening in the iris. The iris controls the size of the pupil. The pupil's function is to adjust the amount of light entering the eye.
• $\small \bf Sclera$ : The outer covering of the eye is called sclera. It is a protective tough white layer (white part of the eye).
• $\small \bf Cornea$ : The transparent part in front of the sclera is called the cornea. Light enters the eye through the cornea.
• $\small \bf Iris$ : It is a dark, muscular tissue and ring-like structure present behind the cornea. The color of the eye is due to the color of the iris. The iris regulates the amount and intensity of light entering the eyes by adjusting its size.
• $\small \bf Retina$ : It is the light-sensitive layer which consists of nerve cells. It's function is to convert the images formed by the lens into electrical impulses. These electrical impulses are then transmitted through optic nerves to the brain.
• $\small \bf Lens$ : The transparent portion situated behind the pupil is called the lens. The lens alters the shape to focus light on the retina, with the help of ciliary muscles. It becomes small to focus objects at a distance and becomes big to focus nearby objects.
• $\small \bf Optic~nerves$ : There are two types of optic nerves :-

1. $\small \rm Cones$ : Cones are the nerve cells that are more sensitive to bright light. Cones help in central and color vision.
2. $\small \rm Rods$ : Rods are the nerve cells that are more sensitive to din light. Rods help in peripheral vision.

• There are no sensory nerve cells at the junction of the optic nerve and retina. Therefore, no vision is possible at this point and is called as Blind spot.

$\large \bf \red {Diagram:-}$

Refer the attachment!