sensory system pt2

lateral rectus

moves eye laterally, abducens VI

medial rectus

moves eye medially, oculomotor III

Superior rectus

elevates eye and turns it medially, oculomotor III

Inferior rectus

depresses eye and turns it medially, oculomotor III

Inferior oblique

elevates eye and turns it laterally, oculomotor III

Superior oblique

depresses eye and turns it laterally, trochlear IV

hyperopia (farsightedness)

trouble seeing close up, fix with convex lens to add power

Myopia (nearsightedness)

trouble seeing far away, fix with concave lens to reduce power

step 1

light enters through pupil

step 2

light passes through the lens and vitreous humor to the retina

step 3

the image projected from the lens on the back of the eye is upside down

step 4

retina has photoreceptors that detect light & sends impulses to the brain

rods

black and white vision; sensitive to light; night vision

cones

color vision & detial; blue, red, green pigment cones detect different wavelengths of light

step 5

impulses from the rods and cones in the retina are sent to the optic nerve

step 6

optic nerves from each eye cross at optic chaisma (left eye to right occipital; right eye to left occipital)

step 7

visual integration centers in the occipital lobe process visual input

presbyopia

the crytaline lens tends to harden with age

astigmatism

curvature of the cornea

red & green color blindness

red or green cones/pigments are missing

Blue color blindness

blue cone/pigments missing

Monochromats

totally color blind

glaucoma

damage to the optic nerve occurs due to increased eye pressure

Cataracts

clouding of the lens that affects vision