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.
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.
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