EYE Flashcards
function of eye
-focus light rays on rods and cones
structures in the anterior chamber of the eye
- aqueous humor
- ciliary body
- canal of schlemn
- cornea
- lens
- pupil
- iris
- conjunctiva
3 layers of the eye are (from innermost to outermost)
- retina
- choroid
- sclera
aqueous humour location
-front of lens
aqueous humour structure
-protein like
how often is the aqueous humour drained, made and recycled
5x a day
where is aqueous humor drained from?
canal of schlemn
where is aqueous humor produced?
ciliary body
function of aqueous humor
carry nutrients for cornea and lens
glaucoma
- no drainage of aq humor and the optic nerve is harmed and loses capability to send messages to the brain and BLINDNESS
how do you correct glaucoma
- surgery
- daily intake of meds
which structure is the anterior extension of the sclera and is transparent
cornea
what structure divides the 2 fluid filled cavities
lens
function of lens
-projects light onto the retina (upside down)
what makes the lens translucent
-apoptosis during fetal development
iris function
vary size of pupil which determines how much light can get in (not all the light reaches through)
which is the pigment part of the eye
the iris
which structure in the anterior chamber s the furthest from the aq humor
iris
pupil is the structure where
light enters and can be adjusted by contracting iris muscles
which mucous membrane covers the entire eye
conjunctiva
bacteria + conjunctiva =
a lot of puss
virus + conjunctiva =
- less puss
- can go undetected
- aka conjunctivitis (pink eye)
structures in the posterior eye
- vitreous humor
- sclera
- choroid layer
- retina
- optic nerve
- fovea
- macula lutea
- optic discs
vitreous humor structure
- covered by sclera
- gel-like
vitreous humor function
- protect eye
- maintain shape and structure
choroid layer function
- anteriorly from the ciliary body and iris
- prevents scattering of light rays in eyes
what layers of the eye has bv tat nourish the retina
-choroid layer
what eye layer make sup the white part of the eye
-sclera
function of retina
has photoreceptors
optic nerve function
-takes visual pathways to the brain
which region of the has the sharpest vision with the greatest acuity ?
fovea
does fovea have rods or cones or both
CONES ONLY, + highest concentration of cones
where is the macula lutea located
fovea
what is the macula lutea
flap of ct that surrounds fovea
macula degeneration is aka
donut vision
what happens in macula degeneration
-degeneration of sharpest vison, losing photoreceptors
-peripheral vision only
BLINDNESS
what eye structure forms the blindspot
optic discs
which structure in the eye has no rods and cones
optic discs
function of optic discs
-full of bvs which the optic nerve leaves through
accommodation meaning
-changing the strength and shape of lens wit the help of suspensory ligaments
when are the suspensory ligaments stretched to the max, taut and tight
sympathetic stimulation of ciliary muscles
when is the lens flat and why
sympathetic stimulation and for far vision
when are the ciliary muscles relaxed
sympathetic stimulation
what happens to the suspensory ligaments during parasympathetic stimulation
they are relaxed and weakened
what happens to the lens during parasympathetic stimulation
they are rounded
when do we need round lens
for near vision
CN 3 nerve aka
oculomotor nerve
function of cn 3
-change lens shape, pupil muscles, and ciliary muscles
which CN is the trochlear nerve
cn 4
function of the cn4, trochlear nerve
-movement of extrinsic eye muscles
cn 5 aka
trigeminal nerve
which nerve is responsible for sensory info for the head and the neck
CN5, trigeminal nerve
which nerve controls extrinsic muscles of the eye
- cn 6, Abducens
- cn4, trochlear
cn 7 aka
facial nerve
which nerve releases and produces tears
cn 7, facial nerve
hyperopia aka
far - sightedness
when is the focus behind the retina
-hyperopia
how can hyperopia be corrected
convex lenses
what is near sightless referred to as
myopia
where does the focal point land in myopia
in front of retina
how can myopia be fixed
concave lens
which seeing problem is the most common
-myopia
what is the shape of the eye ball in myopia
too long
the lens is too strong in which seeing problem
myopia
what causes prebysopia
old age
what happens in prebysopia
- lens start to call out
- lose elasticity
- can accommodate for near vision
what condition is fixed with reading glasses
prebysopia
when is the eyeball too short and the lens is too weak
hyperopia
which eye structure is the extension of the CNS
retina
retina contains
-modified neurones called rods and cones
which photoreceptor is used for night vision
rods
what colour do rods see in
-seeing in shades of grey
which photoreceptor has low acuity and sensitive
rods
location of rods
abundant in peripheral region
what photoreceptor absorbs all wavelengths and can’t discriminate ?
rods
cones are used for seeing in
the day
what are the three colour the cones can see in
red, green, blue
which colour has the Lowest wavelengths
blue
which photoreceptor has high acuity
cones
where are the highest amount of cones located
-centre of retina (fovea + macula lulea)
Nighttime blindness is caused by the deficiency of
Vit A
what’s happens with night blindness
- no transduction
- reduced # of rods
what time of the day can one see With night blindness
- during the day
which condition is a result of missing or malfunctioning red and green cones
colour blindness
opsin structure
outer covering, disc membrane
retinal is a
vit A derivatve
function of retinal
-light absorbing part of photopigment
photopigments def
set that undergoes chemical alterations when activated by light
which segment of a photoreceptor is faces the chord layer and contacts rods and cones that can detect light stimulus
outer segment
what does the inner segment of a photoreceptor contain
-metabolic parts of a cell
outermost layer of the retina is the closet to
the choriod layer
which layer of the retina contains photoreceptors
-outermost layer
where are bipolar cells found in the Retina layers
middle player
which eye cells display graded potential
bipolar cells
which cells are found in the inner layer of the retina
ganglion cells
ganglion cells function
-form ap and transmit info to brain
which cells unite to form the optic nerve (CN2)
ganglion cells
synaptic terminal location
closest to eyes interior
faces bi-polar cells
synaptic terminal function
- transmits small graded potential
- release neurotransmitters
when is the concentration of cGMP high
retina in the dark
what controls and the opening and closing of Na+ channels
concentration of cGMP
how is darkness perceived?
depolarization occurs, inhibitory neurotransmitter is released
when is transducin excited
-when Retinal leaves opsin when light hits the retina
what is activated when light hits the retina
phosphodiesterase
what happens to the cGMP concentration and Na+ when light hits the retina
- Na+ channels close
- decreased concentration of cGMP
what occurs when light hits the Retina
- inhibitory neurotransmitter is not released
- hyperpolarization
- graded potential
- ganglion cells produce ap which goes to the occitpal lobes
- light is perceived
visual pathway
optic nerve -> optic chaism -> optic tract -> lateral geniculate body -> optic radiation
where is visual info crossed
optic chaism
what takes the info to the thalamus
optic tract
lateral geniculate body location
thalamus
which structure is in the visual cortex
optic radiation
which cells allow lateral inhibition
ganglion cells
which type of ganglion is responsible for enhancing image
on - centre
in which gangion cell does depolarization occur
on-centre
what does the off centre ganglion cell allow
periphery vision
which ganglion cell inhibits the cells
off- centre
