EX: 24
What is the function of the tapetum lucidum, and of what benefit is this to the cow?
It reflects light that enters the eye, allowing the image to hit the retina several times before being absorbed. As a result, it increases light stimulation of the different areas of the retina. It works especially well under dim light conditions.
Define accommodation (with respect to physiology to vision).
ability to focus by changing the shape of the lens for close vision
What are the functions of the cornea?
allows light in, protects eye, refracts light
What is the function of the pupil?
allows light to enter the eye (posterior portion)
What is the function of the lens?
allows light to enter the eye and refracts (or bends) light rays
What is the function of suspensory ligaments?
attaches the eye to the ciliary body
What function does the vitreous humor have with respect to the retina?
holds retina against the back of the eyeball, refracts light, and helps sustain internal eyeball pressure
elevates eye and turns is laterally
inferior oblique
depresses eye
inferior rectus
look down. what extrinsic eye muscles are responsible for this action? right eye: ___ left eye: ___
inferior rectus inferior rectus
moves the eye laterally
lateral rectus
What is the functions of the sclera?
leads shape and protection to the eyeball and provides anchoring points for extrinsic eye muscles; seen anteriorly as the white of the eye
lesion in left optic tract Vision left eye: right eye: FOV left eye: rigt eye:
loss of lateral vision loss of medial vision loss of medial FOV loss of lateral FOV
lesion in the right cerebral cortex vision left eye: right eye: FOV left eye: right eye:
loss of medial vision loss of lateral vision loss of lateral FOV loss of medial FOV
Lesion through the optic chiasm vision left eye: right eye: FOV left eye: right eye:
loss of medial vision loss of medial vision loss of lateral vision loss of lateral vision (tunnel vision)
moves eye medially
medial rectus
Look to the left. What extrinsic eye muscles are responsible for this action? right eye: ____ left eye: ____
medial rectus lateral rectus
Look up and to the left. What extrinsic eye muscles are responsible for this action? right eye: ___ left eye: ___
medial rectus and superior rectus inferior oblique
What is the function of the circular muscle?
muscle of the iris which constricts the pupil with parasympathetic stimulation
What is the function of the radial muscle?
muscle of the iris which dilates the pupil with sympathetic stimulation
Lesion in the right optic nerve vision Left eye: right eye: FOV left eye: right eye:
no effect loss of medial and lateral vision (complete loss) no effect total loss on right side
What is the function of the ciliary body?
produces aqueous humor and contains ciliary muscle needed for accommodation.
What 2 specific photo receptors make up the nervous layer of the retina?
rods and cones
depresses eye and turns it medially
superior oblique
elevates eye and turns it medially
superior rectus
What subdivision of the autonomic nervous system controls the radial muscles: ___ circular muscles: ___
sympathetic parasympathetic
What is the function of the optic nerve?
transmits sensory impulses from each eye to the CNS
What is the 2 major functions of the choroid?
vascular tunic- blood vessels supplying nutrients to retina Pigmented for light absorption (prevents light from scattering and reflecting with the eye)
