VISUAL SHIT Flashcards
light stimuli is——- waves
electromagnetic
Shape of the eye is Approximately——-
spherical
The eye has a A tough outer—- layer made of—- ,— ,——
- A middle layer made of——,—-,—-
- An inner neural layer made of ——
fibrous
sclera conjuctiva cornea
ciliary body iris choroid
retina
from out-in=___-____-retina
sclera
choroid
Nerve fibers leaves the eye at the——-
optic disc
Blood vessels supplying the retina enter and leaves the eye through the ——
Optic disc
blood vessels that run over the inner surface of the retina can be examined with an——- (very useful for——- or—— patients)
ophthalmoscope
diabetic
hypertensive
The two inner chamber of the eye contain the anterior —— and posterior—— humor, suspended between these two is the——-.
aqueous
vitreous
lens
The shape of the eye is maintained by an——- of approximately ——mmHg.
intraocular pressure
15
Intraocular pressure itself is maintained by the——-
balance between the formation and drainage of aqueous humor.
aqueous humor is secreted by the——— and flows from—— chamber to——- chamber
Ciliary processes
posterior
anterior
Aqueous humor Drains through the———
canal of Schwemn
abnormal elevation of intraoccular pressure is called ‘——-’ and if untreated can lead to——-
glaucoma
blindness
eye can distinguish two qualities of light: its—— and its———
brightness
wavelength
For humans, the wavelengths between—— and—— nanometers are called visible light
400
750
Visual acuity is highest at a—— point of the retina, called the ——-; light is focused at a depression , called the ——-
central
macula
fovea
How many muscles of eye movement do we have?…
List them
6
4 rectus muscles(Superior, inferior, lateral and medial)
-Two oblique muscles(Superior and inferior)
INNERVATION of the muscles of eye movement?
lat rectus and sup oblique are controlled by CN6 and CN4 respectively
-all others by C.N III
List and define 4 types of movement of the eye
conjugate movement or version:both eyes moving in the same direction
- disjunctive movement or vergences: both eyes moving in opposite direction like in accommodation
- rapid movement or saccades:altering fixation from one object to another
- smooth movement or pursuit:the eyes are fixed on a moving object
In what direction does the superior oblique move the eye?
Downwards
Light is Focused by the———-
Cornea and Lens
Most of the focusing of light is done by the—— which is a transparent section of the——
cornea
sclera
Cornea and Lens. Which is elastic, and which has fixed focus
Cornea is non-adjustable (fixed focus)
-Lens (very elastic) gives fine adjustment to focus
Lenses give—— images
inverted
The—— Controls the Amount of Light Entering the Eye by——-
Iris
constricting and dilating
The—— is the hole in the center of the iris
pupil
The iris has 2 rings of muscles: —- to—— pupil) and —— to—— pupil
Sphincter ; constrict
dilator
open
INNERVATION of the muscles of the iris
sphincter: CN3(para)
- dilator:sympathetic nerves
Lenses—— light waves
refract
The more curved the lens surface the more——-
refraction
The lens is held in place by——-
suspensory ligaments
Contraction of ciliary muscle—— ligaments leading to lens curvature ——- (for—— vision)
relaxes
increasing
near
Relaxation of ciliary muscle leads to lens——- and—— curvature (for—- vision)
flattening
less
far
ciliary muscle is controlled by—— nerve
Occulomotor
The refractive power of the lens is made greater by increasing its——-
surface curvature
power of accommodation is about—— at childhood
10D
Decrease in accommodation of the lens with age is called——?
Presbyopia
When focusing at infinity, the lens is pulled——- by tension in the zonule
flat
Another name for zonules is??
lens ligament
Miosis is??
Constriction of pupil
Constriction of pupil Results in better or worse depth of focus ??
Better
mydriasis is —-?
Dilation of pupil
Mention hard drugs that constrict or dilate the pupil
Constrict: heroin
Dilate: cocaine, amohetamines,marijuana, lsd
Hypermetropia is corrected by —-
Myopia is corrected by —-
corrected by convex lens
Corrected with concave lens
Hypermetropia is also called ——
Myopia is also called ——
long-sightedness, farsightedness
short- sightedness, nearsightedness
In Hypermetropia The axis of the eye is too—- and images of ——— object are focused —— the retina
short
Close
Behind
In Myopia, The axis of the eye is too—- and images of —— objects are focused——- the retina
long
Far
in front of
Astigmatism is corrected with ———
Corrected by cylindrical lens
astigmatism is majorly due to issue with —— and sometimes ——
Cornea
Lens
Define astigmatism
The curvature of the cornea (or occasionally the lens) is different in one plane from that in another , therefore giving different degrees of refraction in different planes.
Near point @ 20 years???
Near point @ age 50 – 60
about 10cm
About 80cm
Presbyopia is due to —- increase and loss of ——— of the lens
inelastic crystalline core (lens nucleus) increases in size and the surrounding lens capsule loses its elasticity
Cataract are——- of the—— and are common in the——.
opacities
lens
elderly
Action potentials are not generated until the ganglion cells——-
converge at the optic disc
The optic disc is also known as the ——
Blind spot
Optic nerves synapse at the ——-
lateral geniculate nucleus of the thalamus
Optic nerves from the—- half of each retina decussate at the——-
nasal
optic chiasm
optic nerves from the——- halves of each retina , stay on the same side
temporal
Mention the layers of the lateral geniculate layers and what region they occupy
magnocellular(top 2) and parvocellular(lower 4) layers
lateral geniculate nucleus project to the——-
visual cortex
The magnocellular system processes information pertaining to—-,—- and——
-The parvocellular system processes information about—- and—-
movement ,texture ,stereoscopic vision
color ,high discrimination of forms and contours
The Pigment cell layer of the retina extends into the—— layer and also convert ——-to ——-and deliver the——- form to the——
photoreceptor
all-trans-retinal
11-cis retinal
11-cis
photoreceptors
Contents of Outer nuclear layer and inner nuclear layer
nuclei of photoreceptors
cell bodies of retinal interneurons including bipolar cells, horizontal cells,and amacrine cells
Contents of the Outer plexiform layer and inner plexiform layer
- synapses between receptor and bipolar,receptor and horizontal , horizontal and bipolar
- Synapses between interneurons and ganglion cells.
—— are the output cells of the retina.
Ganglion cells
Axons of retinal ganglion cells form the——- layer
optic nerve
The Retina Has 2 Types of Light Detectors. List them
Rods & Cones
Rods detect——.
-Cones detect—-.
light and dark
Light and colors
Which is more numerous in the eye. Rods or cones?
Rods
light-sensitive pigments of the eye are ——— and —— derived from——
rhodopsin, iodopsin
vitamin A
———joins outer and inner segment of rods and cones
connecting stalk/cilium
inner segment of cones and rods have ———
mitochondria,golgi,ribosomes and endoplasmic reticulum
Which has more rhodopsin. Rods or cones?
Rods
Difference between the arrangement of pigmented discs of rods and cones
Rods-pigment discs stacked like pennies all the way to the base
Cones-pigment discs taper off toward the base
membranes of discs of ———-are DISTINCT from the plasma membranewhile that of —— is continuous with the plasma membrane
Rods
Cones
——- photoreceptors are Sensitive to dim light
Rods
——-photoreceptors Respond to—- wavelengths (colors) but send only —— to the brain because they——-
Rods
ALL
“grey” information
can’t see color so everything is just shades of black white and grey
——-photoreceptors are Not good for visual acuity
——-photoreceptors are good for visual acuity
Rods
Cones
Cones are primarily concentrated in the——
fovea
all-trans retinal’causes——- of rod
hyperpolarization
The NT commonly used in the eye transmission is ———
Glutamate
——- receptor of glutamate leads to depolarization while —— leads to hyperpolarization
Metabotropic
Ionotropic
List the 3 photopsins you know and their maximum wavelength sensitivity
blue cones:maximum sensitivity at 455 nm
- green cones:maximum sensitivity at 530nm
- red cones:maximum sensitivity at 625nm
Color blindness is most commonly due to mutation in —— cones
Red and green
In light adaptation,——photoreceptors are inhibited. ——-photoreceptors are activated. rhodopsin in rods is ———. Pupil size ——
Rods
Cones
bleached out
Decrease
In Dark adaptation——- photoreceptors begin to cease to be stimulated ;bleached out rods produce——-;———photoreceptors eventually take over in the dim light; pupils size ———
cones
rhodopsin
rods
Increase
night blindness is also called ——
Nyctalopia
night blindness is described as a deficiency in function of—— during——- situations
rods
dim-light
The 3 types of cones can produce sensations of all the colors in the rainbow. T/F
T
When rods or cones are struck by light, they produce a small——-
generator potential
——- tract is the optic radiation of fibers from thalamus to cortex
geniculocalcarine
primary visual cortex is found in which lobe of the cortex and which bodmann’s area?
Occipital lobe
Area 17
List the 3 other brain areas that receive visual information and their function
superior colliculi for control of extrinsic eye muscles
pretectal nuclei - mediate pupillary light reflexes
suprachiasmatic nucleus of hypothalamus - circadian rhythmo
Light impulses are mapped out in - dimensions on the occipital cortex and the Brain constructs a —-dimensional image from the sensory data
2
3-
Nerve from Fovea centralis has a ——-on cortex than nerves from other parts of the retina
much larger area
Hemianopia is ???
the loss of vision in half the visual field of one or both eyes.
The superior colliculus is involved in light reflexes . T/F
T
Pupil dilated or constructs when looking at a near object?
Constrict
Light shone into one eye leads to how many pupils constricting???
2
The afferent pathway for the light reflex is via the optic nerve to the ——-of the mid brain
-The efferent pathway is along parasympathetic fibers of——
pretectal region
C.N III
In the light reflex, the pretectal nuclei stimulates both sides of the——— even though the light was only perceived in the right eye
-rt and left—— generate AP through the right and left CN 3 causing both pupil to constrict
edinger westphal nucleus
edinger westphal nucleus
