the human eye

Question 1

what are the features/functions of the iris?

Answer 1

the iris is a circular sheet of muscles which contain melatonin. a pair of circular and radial muscles control the amount of light entering the eye

Question 2

what are the features/functions of the pupil?

Answer 2

it is a circular opening of the eye, that allows light to enter the eye

Question 3

what are the features/functions of the sclera?

Answer 3

it is an outermost white tough fibrous coat that protects the eye. it progresses to form the transparent cornea in the eye

Question 4

what are the features/functions of the lacrimal gland?

Answer 4

it secrets tears wnich wash dust away, keeps cornea moist and lubricages the conjuctiva

Question 5

what are the features and functions of the conjunctiva?

Answer 5

it is a thin, transparent membrane covering the sclera, helping to lubricate the eye

Question 6

what are the features/functions of the cornea?

Answer 6

it is a dome shaped, transparent refractive layer causing light rYs to converge towards the pupil, causing the greatest refraction

Question 7

what are the features/functions of the retina?

Answer 7

it is the innermost layer containing photoreceptors. nerve impulses generated are transmitted towards brain along sensory neurons in the optic nerve.

Question 8

what are the features/functions of the fovea?

Answer 8

it contains the highest concentration of cones, with no rods

Question 9

what are the features/functions of the choroid?

Answer 9

it is the middle layer, pigmented black to prevent TIR, contains blood vessels, and provides oxygen and glucose to retina and removes waste

Question 10

what are the features/functions of the lens?

Answer 10

it refracts to focus light on the retina, due to the elastic and flexible nature of it. edge is attached to cillary body by suspensory ligaments. the curvature of the lens can be altered

Question 11

what are the features/functions of the blind spot?

Answer 11

there are no photoreceptors where the optic nerve leaves the eye

Question 12

what are the features/functions of the optic nerve?

Answer 12

it transmits nerve impulses from the retina to the brain, when photoreceptors are stimulated and from brain back to effectors for response

Question 13

what are the features/functions of the cillary muscles?

Answer 13

they contract and relax to change the thickness of the lens

Question 14

what are the features/functions of the suspensory ligament?

Answer 14

they attach the lens to the cillary body, and taut and slacken

Question 15

what are the features/functions of the aqueous/virtuous humour?

Answer 15

they help to maintain the shape of the eyeball by providing an internal fluid pressure, and help to refract light

Question 16

what are the features/functions of the rectus muscles?

Answer 16

they are attached on the outside of the eyeball, and control movement

Question 17

how does the eye work?

Answer 17

light entering the eye is refracted by the cornea and the lens, which stimulates photoreceptors on the retina. nerve impulses generated are transmitted along sensory neurons in the optic nerve to the brain and back to the eye