Lecture 7: Eye And Adenxa Flashcards Preview

CHI 280: Human Anatomy I > Lecture 7: Eye And Adenxa > Flashcards

Flashcards in Lecture 7: Eye And Adenxa Deck (28)
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Know how to label the picture on slide 4

Do it nigs


Know the 6 muscles of the eye slide 7
Their innervation and muscle action

Superior rectus- oculomotor nerve, elevates, and laterally rotates the eyeball
Inferior rectus- CN 3- depresses, adducts, and rotates eyeball laterally
Lateral rectus- CN 6- abducts eyeball
Medial rectus- CN 3- adducts eyeball
Superior oblique- CN 4 (trochlear)- abducts, depresses, and medially rotates eyeball
Inferior oblique- CN 3- abducts, elevates, and laterally rotates eye
Levator palpebrae superioris- CN3- elevates superior eyelid


All eye muscles are the oculomotor nerve except?

Torochlear (4) superior oblique (goes through a trochlear)
Abducent CN 6: lateral rectus


What muscles are used to close eyelids?
To open eyelids?

Orbicularis oculi contracts and levator palpebrae relaxes
To open: levator palpebrae superioris contracts


What are the glands that secrete oily substance into tears?

Tarsal glands


What is the syndrome were you have a drooping superior eyelid cause by loss of sympathetic innervation to superior tarsus muscle.

Ptosis: in Horners syndrome


Be able to label the diagram in slide 21



Be able to label the bones making the orbit on slide 22



What are the parts that make u the lacrimal apparatus?
Picture on slide25

Consist of the:
Lacrimal gland: secretes lacrimal fluid (watery physiological saline containing lysozyme and O2)
Excretory ducts: lacrimal fluid from gland to conjunctival sac
Lacrimal canaliculi (small canals)
Lacrimal punctum (opening)
Lacrimal papilla
Lacrimal lake (where tears collect)
Lacrimal sac (diluted superior part of duct)
Nasolacrimal duct --> inferior nasal meatus


What is the parasympathetic innervation of the lacrimal gland?

Secretomotor parasympathetic fibre from facial nerve (CN 7) via pterygopalatine ganglion
Sympathetic: inhibits tears
Parasympathetic: creates tears


Were do the retina, iris and optic nerve originate from?
What forms from the ectoderm?

The brain. Reason why the optic nerve is coated in the 3 layers of the cranial meninges!
Surface ectoderm --> lens, cornea, conjunctiva, eyelashes, lacrimal glands.
Mesenchyme--> choroid, sclera, tarsal plates, orbicularis oculi


Describe the optic tract

The optic nerves meet at the optic chiasm then to the optic tract and end at the lateral geniculate body (midbrain)


Rods and cones. What do they specialise in?

Rods: dim light, peripheral vision receptors
Cones: bright light, high acuity colour receptors


Normal retina
What is the optic disc
Fovea centralis

Optic disc: blind spot, where retinal ganglion cell nerve axons leave retina in optic nerve and pass to brain
Fovea centralis: area of macula with most accurate vision, only comes


What used to be in the hyaloid canal?

Because when we are an embryo less than 10 weeks old we have an artery that is supplying the lens and letting it grow. It regresses and it no longer gets supplied from blood vessels. Instead lens will get nutrients from the vitreous fluid


What is the function of the vitreous body?

-holds the eye in shape
-vision, it is a high density substance which magnifies and refracts the light to focus it onto the fovea centralis


Tunic of the eyeball
Label diagram on slide 35

Fibrous: sclera (white): tough, opaque, supplied by arteries cornea (clear): transparent, avascular, highly innervated by nerves from CN5-V1
Vascular: choroid, ciliary body, and iris
Nervous coat: retina (2 layers, neural layer and retinal pigmented epithelium) important because it changes the colour of our eyeball


Corneal blink reflex:
Afferent limb (sensory) ie which nerve is sensory to brain
Efferent limb (motor from brain)

Afferent: opthamic branch from trigeminal
Efferent: facial



Clouding of lens
Scatters light entering the eye ie light can't focus so will make vision blurry
- fixed by removing lens and replacing it


Aqueous humour

Fills and shapes anterior and posterior chambers of eye
-provides nutrients to avascular lens and cornea, removes wastes
-secretion from ciliary processes
-ciliary processes --> posterior chamber --> through pupil --> anterior chamber
-circadian rhythm of flow: higher in morning than at night


Glaucoma. What is this condition

Impaired aqueous humour outflow
Elevated intracellular pressure
Optic nerve damage


Ciliary body and iris

Ciliary body connect choroid to iris
Ciliary body processes secrete aqueous humour
Autonomic innervation of muscles of iris.


What is the disease when there is a hole in the iris?



Pupillary reflexes

Slow sympathetic response ie dilation
Fast parasympathetic fibres by ciliary nerves ie constriction
Under autonomic control


What happens when there is an absence of nerve stimulation to the eye?

The ciliary muscle relax, the k
Zonular fibres are under tension
Lens is stretched then to refract light for distant vision


What happens when parasympathetic stimulation causes ciliary muscle to contract?

Zonular fibres relax.
In the absense of stretching, internal tension causes lens to become more spherical (thicker) to refract light for near vision


What happens when the aqueous humour pressure decreases?

It may cause the retina to separate slide 50.
Vision impairment and blindness


Macula degeneration

Chronic disease no cure,
Leading causes of blindness