The visual system Flashcards by Ethan Furtado

Where does the eyeball sit in

Bony orbit

How well did you know this?

Not at all

Perfectly

What three parts can the eyeball be divided into

fibrous
vascular
inner

How well did you know this?

Not at all

Perfectly

What three parts can the eyeball be divided into

fibrous
vascular
inner

How well did you know this?

Not at all

Perfectly

What is the outer most layer of eye

Fibrous layer

How well did you know this?

Not at all

Perfectly

What is the function of fibrous layer

Provide shape to the yee and support deeper sturcutresa

How well did you know this?

Not at all

Perfectly

What is the sclera

Majority of the fibrous layer

provides attachment for the extraocular muscles

How well did you know this?

Not at all

Perfectly

What is the cornea

Transparent and centrally position part of fibrous layer

Light entering the eye is refracted by the cornea

How well did you know this?

Not at all

Perfectly

What is the vascular layer made up of

Choroid
Ciliary body
Iris

How well did you know this?

Not at all

Perfectly

What is the choroid

Connective tissue and blood vessels

Provides nourishment to the outer layer of the retina

How well did you know this?

Not at all

Perfectly

What is the ciliary body

Comprised of the ciliary muscle and ciliary processes

Controls the shape of the lens and contributes to the formation of aqueous humor

How well did you know this?

Not at all

Perfectly

What are the ciliary muscles

Collection of smooth muscle fibres, which are attached to the lens by ciliary processes

How well did you know this?

Not at all

Perfectly

What is the iris

Circular structure with an aperture in the centre

Pupil diameter is altered by smooth muscle fibres within the iris, innervated by the autonomic nervous system

How well did you know this?

Not at all

Perfectly

What is the macula

In the macula Yellowish layer that contains fovea, which contains high concentration of light detetcing cells
Responsible for high acuity vision

How well did you know this?

Not at all

Perfectly

What is the lens

Located anteriorly between the virtous humor and the pupil

Shape of the lens is altered by ciliary body, altering its refracting power

How well did you know this?

Not at all

Perfectly

What are the anterior and posterior chambers

areas filled with aqueous humor
Anterior chamber located between iris and cornea
Posterior chamber between iris and ciliary processes

How well did you know this?

Not at all

Perfectly

What is the aqueous humor

Clear plasma like fluid that nourishes and protects the eye

Porudced constantly and drain via the trabecular meshwork

How well did you know this?

Not at all

Perfectly

what is the trabecular meshwork

Area of tissue at the base of the cornea

How well did you know this?

Not at all

Perfectly

What is elevation and depression

Elevation is movement of eyeball superiorly

Depression is movement of eyeball inferiorly

How well did you know this?

Not at all

Perfectly

What is abduction and adduction of eyeball

Abduction - lateral movement of eyeball

Adduction - medial movement of eyeball

How well did you know this?

Not at all

Perfectly

What are the 7 extrinsic muscles of the eye

Superior rectus
inferior rectus
medial rectus
lateral rectus
superior oblique
Inferior oblique
Levator palpebrae superioris muscle

How well did you know this?

Not at all

Perfectly

What is the only extrinsic muscle that acts on the eyelid

Levator palpebrae superioris

Attachments of the Levator palpebrae superioris

Originates from the lesser wing of the sphenoid bone, immediately above the optic foramen
Attaches to the superior tarsal plate of the upper eyelid

What innervates the Levator palpebrae superioris

Oculomotor nerve

Where do the four recti muscles originate from

Common tendinous ring

Attachment of superior rectus

Originates from the superior part of the common tendinous ring and attaches to the superior and anterior aspect of the sclera

Action of superior rectus

Elevation | also contributes to adduction and medial rotation of the eyeball

Attachment of inferior rectus

Originates from the inferior part of the common tendinous ring and attaches to the inferior and anterior aspect of the sclera

Action of inferior rectus

Depression | Contributes to adduction ad lateral rotation of the eyeball

Attachment of the medial rectus

Originates form the medial part of the common tendinous ring and attaches to the anteromedial aspect of the sclera

Action of the medial rectus

Adducts the eyeball

Attachment of the lateral rectus

Originates from the lateral part of the common tendinous ring and attaches to the anterolateral aspect of the sclera

Action of the lateral rectus

Abducts the eyeball

Innervation of the recti muscles

All innervated by oculomotor | except lateral rectus - innervated by abducens

Attachment of superior oblique

Originates from the body of the sphenoid bone | Tendon passes though a trochlea and then attaches to the sclera of the eye posterior to the superior rectus

Action of the superior oblique

Depresses, abducts and medially rotates the eyeball

Attachment of inferior oblique

Originates from the anterior aspect of the orbital floor | attaches to the sclera of the eye posterior to the lateral rectus

actions of the inferior oblique

Elevates, abducts and laterally rotates the eyeball

Innervations of the oblique muscles of eye

Superior - trochlear | Inferior - Oculomotor

What does the parasympathetic part of the oculomotor nerve innervate in the eye?

supplies the sphincter papillae and the ciliary muscles of the eye

Through what does the oculomotor nerve enter the cranial cavity What happens to the nerve past this point

Via the superior orbital fissure | Divided into the superior and inferior branches

What does the sphincter pupillae do?

constricts the pupil

Through what does the trochlear nerve exit the cranial cavity

Superior orbital nerve

Where does the trochlear nerve arise from

Posterior aspect of the midbrain

Where does the abducens nerve arise rom and where does it exit the cranial cavity from

Exits the brainstem at the junction of the pons and the medulla Exits the cranial cavity through superior orbital fissure

How is the optic nerve formed

Convergence of axons from the retinal ganglion cells

Where does the optic nerve travel after it's formation

Leaves bony orbit via the optic canal | Enters the cranial cavity running along the surface of the middle cranial fossa

What is the optic canal

A passageway through the sphenoid bone

What is the optic chiasm

Within the middle cranial fossa, optic nerve from each eye unite to form the optic chiasm Fibres from the nasal (medial) half of each retina cross over to the contralateral optic tract, while fibres from the temporal (lateral) halves remain ipsilateral

What does the left optic tract contain

Fibres from the left temporal retina and the right nasal retina

What does the right optic nerve contain

Fibres from the right temporal retina and left nasal retina

How does brain process sensory data from eye

Each optic nerve travels to its corresponding cerebral hemisphere to reach the lateral geniculate nucleus Axons from the LGN then carry visual information via the optic radiation Once at the visual cortex, the brain processes the sensory information and response appropriately

What is the lateral geniculate nucleus

A relay system located in the thalamus