Introduction and Anatomy Flashcards
where are blood-eye barriers?
ciliary epithelium
blood vessels
retinal pigment epithelium
what are the three tunics of the globe?
fibrous
vascular
neurologic
what does cranial nerve IV innervate with reference to the eye?
dorsal oblique muscle
what leads to focusing of an image on the retina?
refraction
convergence
what can change curvature or position of the lens?
ciliary body contrature
what does pupil size affect with focus?
depth of focus
what is hyperopia?
image in focus behind the retina- farsighted
how can you assess refractive error?
streak retinoscopy (skiascopy)
what are cone photoreceptors like?
lower sensitivity
higher acuity
less summation
color perception
what can second-order cells do with the signal they receive?
preserve or invert it
what forms the optic nerve?
axons of retinal ganglion cells
does a normal pupillary light reflex mean an animal can see?
no
how is the visual cortex organized?
retinotopically
where is the only place the CNS can be seen directly?
eyes
what is in the neurologic tunic of the globe?
retina
what are the extraocular muscles?
dorsal, ventral, medial, lateral rectus
dorsal and ventral obliques
retractor bulbi
what cranial nerves innervate the eye and extraocular muscles?
CN III
CN IV
CN VI
can pupil size and shape compensate for some lens-induced errors in focusing?
yes
what is myopia?
image in front of retina
nearsighted
what is hyperopia?
image in focus behind retina
farsighted
what is visual acuity determined by?
distribution and types of retinal cells
what are rods like?
high light sensitivity
lower acuity
greater summation
what is the primary determinant of acuity?
distribution and density of photoreceptors
can retinal ganglion cells transmit information to brain even when photoreceptors are not functioning?
yes
why PLR does not equal vision
how much crossover do horses have for decussation?
85%
