Special Senses: Visual System Flashcards
what are the muscles of the eye
lateral rectus medial rectus superior rectus inferior rectus interior oblique superior oblique
Moves eye laterally
lateral rectus
moves eye medially
medial rectus
elevates eye and turns it medially
superior rectus
depresses eye and turns i medially
inferior rectus
elevates eye and turns it laterally
interior oblique
depresses eye and turns it laterally
superior oblique
shade and prevent sweat from entering the eyes
eyebrows
protect eyes and spread lacrimal fluid (tears) with blinking
eyelids (palpebrae)
secrete an oily secretion that lubicates the surface of the eye
tarsal glands
secrete an oily secretion that lubricates the surface of the eye and the eyelashes
ciliary glands (sty-infection of ciliary gland)
secrete mucus to lubricate the eye
conjunctivae; conjunctivitis-pink eye
form the corners of the eyes
medial and lateral commisures
secretes a whitish oily secretion for lubrication of the eye
lacrimal caruncle
Protects the eye by keeping it moist
lacrimal apparatus
secretes lacrimal fluid, which contains mucus, antibodies, lysozyme
lacrimal gland
allow lacrimal fluid to drain into the superior and inferiorly located lacrimal canaliculi
lacrimal puncta
allow lacrimal fluid to drain into the lacrimal sac
lacrimal canaliculi
allows lacrimal fluid to drain into the nasolacrimal duct
lacrimal sac
allows lacrimal fluid to flow into the nasal cavity
nasolicrimal duct
control the movement of each eyeball and hold eyes in the orbits
extrinsic eye muscles
Depth perception is also called
three dimensional vision
Describe depth perception
each eye has visual field of 170 degrees; 2 visual fields overlap, but each eye sees a slightly different view; visual cortex fuses they slightly different images delivered by the 2 eyes
helps maintain shape of eyeball and provide attachment point for extrinsic eye muscle
sclera
forms clear window that’s the major light bending medium of eye
cornea
blood vessels nourish the other layers of the eye and the melanin helps to absorb excess light
choroid
contains the ciliary muscle and ciliary process
cilary body
alters shape of lens with contraction and relaxation
cilliary muscle
capillaries of the ciliary process form the aqueous humor by filtering plasma
ciliary process
attaches lens to ciliary process
ciliary zonule (suspensory ligament)
controls amount of light entering eye by changing size of pupil diameter
iris
allows light to enter eye
pupil
absorbs light and prevents it from scattering in the eye; pigment cells act as phagocytes for cleaning cell debris; store vitamin a needed for photorecptor renewal
pigmented layer of retina
photoreceptors respond to light and convert light energy into action potentials that travel to primary visual cortex of brain
neural layer of retina
Cells of the retina include what
pigment cells of outer pigmented layer and neurons of neural layer
what 3 major populations of neurons located in inner neural layer
photoreceptors, bipolar cells, ganglion cells
respond to light
photoreceptors
what are 2 photoreceptors
rods and cones
specialized photoreceptors for dim light
rods
color photoreceptors that permit high levels of visual acuity, but only function under conditions of high light
cones
T or F. light must pass through the ganglion cell layer and bipolar cell layer to reach and excite the rods and cones
T
what happens to the photoreceptors as a result of light stimulus
they undergo changes in their membrane potential that influence bipolar cells, which stimulate ganglion cells
how do the axons of the ganglion cells leave the retina
in tight bundles of fibers known as optic nerve
Interneurons that play a role in visual processing
horizontal cells and amacrine cells
