हिंदी

The Human Eye - Structure of the Eyeball

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Topics

  • Definition: Sclerotic Layer (Sclera)
  • Definition: Cornea
  • Definition: Choroid Layer
  • Definition: Ciliary Body
  • Definition: Iris
  • Definition: Pupil
  • Definition: Retina
  • Definition: Rod Cells
  • Definition: Cone Cells
  • Key Points: Structure of the Eyeball
CISCE: Class 10

Definition: Sclerotic Layer (Sclera)

The tough, white outer layer of the eyeball made of fibrous tissue, visible as the white part of the eye.

CISCE: Class 10

Definition: Cornea

The transparent, bulged-out front part of the sclera that covers the coloured part of the eye and allows light to enter.

CISCE: Class 10

Definition: Choroid Layer

The middle, dark-pigmented layer of the eye rich in blood vessels; it nourishes the eye and prevents light scattering.

CISCE: Class 10

Definition: Ciliary Body

A muscular part of the choroid layer that changes the shape of the lens to focus light on the retina.

CISCE: Class 10

Definition: Iris

The coloured part of the eye (extension of choroid) that controls the size of the pupil using circular and radial muscles.

CISCE: Class 10

Definition: Pupil

The circular opening in the centre of the iris that regulates the amount of light entering the eye.

CISCE: Class 10

Definition: Retina

The innermost light-sensitive layer of the eye containing rod and cone cells that detect light and colour.

CISCE: Class 10

Definition: Rod Cells

Light-sensitive cells in the retina that work in dim light and contain the pigment rhodopsin; they do not detect colour.

CISCE: Class 10

Definition: Cone Cells

Light-sensitive cells in the retina responsible for colour vision and bright light, containing the pigment iodopsin.

CISCE: Class 10

Key Points: Structure of the Eyeball

  1. The eyeball has three layers: outer sclerotic, middle choroid, and inner retina.
  2. The sclerotic layer is tough and white, forms the visible white part, and its front part forms the transparent cornea.
  3. The choroid layer is rich in blood vessels and dark pigment; it nourishes the eye and prevents internal reflection of light.
  4. The ciliary body and iris are extensions of the choroid; the iris controls the size of the pupil to regulate light entry.
  5. The pupil widens in dim light and constricts in bright light, controlled by radial and circular muscles.
  6. The retina is the innermost layer containing light-sensitive rods and cones.
  7. Rod cells detect dim light; cone cells detect bright light and color and are concentrated in the yellow spot.
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