Biology
State the functions of the following:
(i) Eyelids
(ii) Eyelashes
(ili) Tears
(iv) Iris
(v) Ciliary muscles
Answer
(i) Eyelids — Protects the outer surface of the eyes and can shut out light.
(ii) Eyelashes — Prevent falling of large particles into the eye.
(ili) Tears — serve as lubricant, washes away dust particles.
(iv) Iris — regulates the amount of light that can enter the eye.
(v) Ciliary muscles — It changes the shape of the lens during accommodation reflex.
Related Questions
Write in proper sequence the names of all the parts of the human eye through which the light rays coming from an object pass before they form an image on the retina.
Name the following :
(i) Place of best vision in the retina of the eye
(ii) Place of no vision in the retina of the eye
(iii) Kind of retinal cells sensitive to dim light
(iv) The circular opening enclosed by iris
(v) The fibres which collectively hold the lens in position
(vi) Capacity of the eye to focus at different distances
(vii) The kind of lens required to correct near sightedness
(viii) The layer of the wall of the eye-ball that corresponds to the black lining of the box of a camera
Give the reason for the following:
(i) Medicines dropped in the eye flow down into the nose.
(ii) A person from bright sunlight outside enters a poorly lit room and feels blinded for a short while.
Categorise the following parts under
(i) external (ii) middle (iii) internal ear.
Ear drum, hammer, pinna, cochlea, anvil, stirrup, eustachian tube, tympanum, oval window, semi-circular canals.