Question

Draw a diagram showing the vertical section of the human eyeball and label the following parts.
a. Cornea
b. Yellow spot

Answer 1

Hint: The sense organ in the human body that reacts to light and helps in vision is called the eye or human eye. There are two types of cells present in the human eye named as rod and cone cells. The nerves of the human eye are directly connected to the brain. It works just like a camera and allows the things visible to a person.

Complete answer:

(a) Cornea – The clear outer layer which is present in the front of the eye is called the cornea. The pupil, iris, and anterior chamber of the eye are covered by the cornea. The refraction or bending of light is the major function of the cornea. The light which enters the eye should be focused properly and this is done by the cornea. It is composed of proteins and cells. The blood vessels are not present in the cornea. The human eye tears and aqueous humor provide nutrients to the cornea due to lack of blood vessels.

There are 5 layers comprised in the cornea:
- Epithelium
- Bowman’s layer
- Stroma
- Descemet’s membrane
- Endothelium

The cornea has the capability to repair itself from minor injuries but deeper abrasions may cause a problem and scars which can lose the transparency of the cornea that leads to visual impairment.

(b) Yellow spot – The abnormal eye growth that usually presents on the sclera near the cornea is called a yellow spot. It is oval-shaped and 1.5 millimeters in size. It is also called macula. This will help to see things with the highest clearness. The yellow spot is composed of the maximum number of cone cells.

The parts in which the yellow spot is divided are:
- Umbo
- Foveola
- Foveal
- Avascular zone
- Parafovea
- Perifovea areas

Note: The human eye is that organ of the body without which you cannot see anything in this world. The people who are blind cannot see anything because of some eye injuries or loss of eye cells. The retina is the main part of the human eye on which the image of an object falls and becomes clear. The various parts of the eye perform different functions so that one can see the object properly.