Week 6 - The Eye

Question 1

outer layer - fibrous tunic

Answer 1

formed by the anterior cornea and posterior sclera

Question 2

sclera

Answer 2

white of the eye; a tough fibrous coat that protects the inner parts of the eye and gives shape to the eye

Question 3

cornea

Answer 3

main function is to refract rays of light to focus them onto the retina

Question 4

middle layer - vascular tunic

Answer 4

formed by the anterior ciliary body, posterior choroid, and iris

Question 5

ciliary body

Answer 5

extends from the retina to the base of the iris; alters the shape of the lens for focusing; secretes aqueous humor

Question 6

choroid

Answer 6

dark brown membrane that lines the sclera; high blood supply to nourish the retina; pigmented to absorb light rays

Question 7

iris

Answer 7

coloured part of the eye; a diaphragm that alters the size of the pupil

Question 8

pupil

Answer 8

changes in size depending on the contraction of an antagonistic pair of muscles (circular and radial muscles); allows light rays to enter eyes

Question 9

sphincter pupillae muscle contracts

Answer 9

pupil size decreases (parasympathetic)

Question 10

dilator pupillae muscle contracts

Answer 10

pupil size increases (sympathetic)

Question 11

inner layer - retina

Answer 11

lines the posterior side of the eyeball; involved in image formation; contains nervous tissue layer and pigmented layer; stores vitamin A

Question 12

macula lutea

Answer 12

the small area at the center of the retina

Question 13

fovea

Answer 13

the small depression in the center of the macula, with the highest concentration of cones (photoreceptors)

Question 14

optic disc

Answer 14

where the ganglion neurons bend posteriorly from the optic nerve (aka blind spot)

Question 15

lens

Answer 15

completely transparent and lies posterior to the iris; focuses light rays on the retina; suspended in the ciliary body by suspensory ligaments (zonula fibers); divides the eye into anterior and posterior cavities

Question 16

conjunctiva

Answer 16

a thin mucous membrane which lines the eyelids and covers the front surface of the eyeball (but not the cornea); keeps the eyeball moist

Question 17

anterior cavity: between the cornea and lens

Answer 17

filled with aqueous humour; functions to maintain pressure on the eyeball for clear vision and supplies the lens and cornea with nutrients

Question 18

posterior cavity: between the lens and retina

Answer 18

filled with vitreous humour; prevents the eyeball from collapsing and to hold the retina against the choroid

Question 19

lacrimal apparatus

Answer 19

makes and drains tears; tears clean and moistens eyes, protect against bacterial infection