Chapter 15: Sight

Question 1

What are the accessory structures of the eye?

Answer 1

eyebrow

eyelid

eyelashes (“ciliary glands” and “meibomian glands”)

conjunctiva

Question 2

lacrimal apparatus

Answer 2

the structure that produces tears. lacrimal gland produces tears that pass over the eye and then drains into the nasal cavity.

Question 3

what are the three layers or “tunics” of the eye?

Answer 3

fibrous

vascular: extends from the carotid arteries and contains melanin

nervous

Question 4

sclera

Answer 4

the white of the eye and the outermost layer of the eye. It is fibrous tissue and is continuous with the cornea. The collagen fibers are large and opaque

Question 5

cornea

Answer 5

the transparent window into the eye with a lot of sqaumous cells for protection. the collagen fibers are small and transparent. the function of the cornea is to bend the light

Question 6

iris

Answer 6

part of the vascular tunic of the eye.

the colored part of the eye also has the smooth muscles that determine the size of the pupil (“sphincter pupillae” and “dilator pupillae”)

Question 7

ciliary body

Answer 7

part of the vascular tunic of the eye.

produces the aqueous humor that fills the anterior chamber. contains the ciliary muscles that control the shape of the eye, and attach to the lens.

Question 8

retina

Answer 8

part of the nervous layer.

has two layers itself. the “pigmented” simple cuboidal epithelium which functions as a filter that separates sensory cells and reduces light. also the sensory retina, which is the inner layer of rod and cone shaped cells that are sensitive to light.

Question 9

lens

Answer 9

a transparent biconvex structure made of epithelial cells

Question 10

what are the functions of the eye?

Answer 10

sensing visible light

refraction or bending of the light

convergence of the light onto a surface

focal point: the point where light rays converge and cross

focus: causing light to converge

Question 11

rods

Answer 11

bipolar photoreceptors that pick up black and white vision. more sensitive to light than cones, which is why you can still see stuff in the dark.

Question 12

cones

Answer 12

a bipolar photoreceptor cell that picks up color

Question 13

myopia

Answer 13

nearsightedness caused by a cornea/lens that is too powerful, or the eyeball is too long. corrected by LASIK and radial keratotomy.

Question 14

hyperopia

Answer 14

farsightedness caused by a cornea/lens that is too weak. Only corrected by a convex lens.

Question 15

presbyopia

Answer 15

increase in near point vision due to age.

Question 16

glaucoma

Answer 16

increase intraocular pressure by aqueous humor buildup

Question 17

diabetes

Answer 17

dysfunction of peripheral circulation

Question 18

astigmatism

Answer 18

there’s not a uniform curve to the cornea, so light that goes through doesn’t refract correctly

Question 19

cataract

Answer 19

clouding of the lens