VISUAL SHIT Flashcards by Iseoluwa Ojo

light stimuli is——- waves

electromagnetic

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Shape of the eye is Approximately——-

spherical

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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

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from out-in=___-____-retina

sclera

choroid

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Nerve fibers leaves the eye at the——-

optic disc

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Blood vessels supplying the retina enter and leaves the eye through the ——

Optic disc

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blood vessels that run over the inner surface of the retina can be examined with an——- (very useful for——- or—— patients)

ophthalmoscope

diabetic

hypertensive

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The two inner chamber of the eye contain the anterior —— and posterior—— humor, suspended between these two is the——-.

aqueous

vitreous

lens

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The shape of the eye is maintained by an——- of approximately ——mmHg.

intraocular pressure

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Intraocular pressure itself is maintained by the——-

balance between the formation and drainage of aqueous humor.

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aqueous humor is secreted by the——— and flows from—— chamber to——- chamber

Ciliary processes

posterior

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Aqueous humor Drains through the———

canal of Schwemn

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abnormal elevation of intraoccular pressure is called ‘——-’ and if untreated can lead to——-

glaucoma

blindness

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eye can distinguish two qualities of light: its—— and its———

brightness

wavelength

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For humans, the wavelengths between—— and—— nanometers are called visible light

400

750

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Visual acuity is highest at a—— point of the retina, called the ——-; light is focused at a depression , called the ——-

central

macula

fovea

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How many muscles of eye movement do we have?…

List them

4 rectus muscles(Superior, inferior, lateral and medial)
-Two oblique muscles(Superior and inferior)

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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

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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

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In what direction does the superior oblique move the eye?

Downwards

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Light is Focused by the———-

Cornea and Lens

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Most of the focusing of light is done by the—— which is a transparent section of the——

cornea

sclera

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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

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Lenses give—— images

inverted

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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 membrane while 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

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

Pupil dilated or constructs when looking at a near object?

Constrict

Light shone into one eye leads to how many pupils constricting???

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