147 & 148 Visual system I and II Flashcards
where does the optic nerve terminate
lateral geniculate nuclei of the thalamus
what does the fibrous layer consist of
sclera and cornea
what is the purpose of the middle (vascular) layer
focusing and regualting the intensity of light
what does the cilliary body produce
aqueous humor
contraction of the cilliary muscles result in
decreased tension on suspensory ligament, allows lens to increase in thickness, focusing light rays on near object
constrictor muscle is under the influence of
parasympathetics
dilarot muscle is under the influence of
sympathetic control
what does light pass through
cornea, aqueous humor, lens vitreous body
what is the main refractive structure of the eye
cornea
when aqueous humor is drained it goes through
trabecular meshwork and into the sinus venosus sclerae
what happens when aquous humor fails to drain
increases intraocular pressure, leads to glaucoma
what does the term presbyopia mean
failure of the lens to accomadate, happens with age
what is opacification of the lens called
cataract
what is the condition when debris from photoreceptor cells accumulate between the photoreceptor cell layer and the pigment epithelial layer
retinitis pigmentosa
rods are sensitive to
light
cons are responsible for
color
what is more pedominate in the peripheral zone
rods
the fovea only consist of
cones
what is the first order neuron of rods and cones? second order neuron
bipolar cell, ganglion cell
which cells modulate transmission between photoreceptor and bipolar cells
horizontal
what cells modulate transmission between bipolar and ganglion cells
amacrine
what is the area for acute vision
fovea
what happens to rhodopsin when absorbing light and where is it found
in rods, rhodopsin is broken down into retinal and opsin, dependent on vitamin A
where is iodopsin
cones
what matte surroudns the optic nerve
dura arachnoid and pia
what is papilleddema
when the optic nerve becomes compressed
where is the primary visual cortex
medial surface of the occipital lobe
which visual field forms meyers loop and passes inferiorly
superior visual field
visual defects are ______ when confined to the same part of the visual field in each eye
homonymous
lesions in front of the optic chiasm are
heteronymous
lesions distal to optic chiams are
homonymous
total destruction of the optic tract, lateral geniculate nucleus, or visual cortex results in
loss of entire opposite field of vision
what three reflexes dictate size of pupil and curvature of the lens
light or pupillary constriction reflex
pupillary dialation reflex
accommodation reflex
int he light reflex, impulses enter the
brachium of the superior colliculus
consensual light reflex involves
contralateral edinger-westphal nucleus
what is the near triad
convergence of the eyes, pupillary constriction, thickening of lens
what nuclei is responsible for convergence of the eye
somatic nuclei
horner syndrome is the loss of ______ to one side of the face
sympathetics
