Beyond the Senses

Sense Organs: Organs that helps us to be aware of our surroundings are known as sense organs.

Receptors: Any cell or tissue sensitive to a selective stimuli are called receptors.

Eye

Composed of three layers:

• Outermost layer- sclera and cornea
• Middle layer- choroid, ciliary body, iris
• Innermost layer- retina, with rod cells and cone cells.

• Just behind the iris, a transparent, biconvex, and elastic structure called lens is present.

• Rods – Contain rhodopsin pigment that is highly sensitive to dim light

• Cones – Contain iodopsin pigment that is sensitive to high intensity light. Cones are also responsible for colour vision.

• Blind spot – Area where photoreceptors such as rods and cones are absent

• Fovea – Area that contains only cones. Vision is finest and sharpest in this zone.

• Aqueous chamber – Space between cornea and lens; contains aqueous humour.

• Vit…