Lecture 34. Special sense Flashcards
What is embedded in the extra occular fat
nerves and blood vessels
what are the attachments of the levator palpebrae superioris muscle
conjunctivia and the tarsal plate, connective tissue in the eyelid
What innervates the levator palpebrae superioris
CN3, parts of the fibers are also innervated by the sympathetic fibers.
What happens if patient cannot fully open eye
ptosis, signs of injury to sympathethic nervous system
What supplies sympathetic fibers to head and neck
T1
What is the conjunctiva
single layer epithelium that covers the cornea
What is the conjunctiva sac
the reflection of the conjunctivia that collects tears
What are the 3 layers of the eyeball
- fibrous
- vaculature
- nervous
What composes the fibrous layer of the eye
posterior 5/6 : sclera
anterior 1/6: cornea
What is the function of the sclera
protect the eyeball
shapes the eyeball
attachment site for the extraocular muscle
allows penetration of the optic nerve and opthalmic artery
What penetrates the sclera
optic nerve and opthalmic artery
What is the function of the cornea
focus light on the retina
What composes the vascular layer of the eye
posterior 5/6: chorioid : supplies blood to retina
anterior 1/6 turns into
-ciliary body : mass of smooth muscle fibers
- iris: controls the size the pupil ( smooth muscle fibers)- disc that sits in front of lens
How are the cilliary body connected to the lens
through suspensory ligaments (tendons of ciliary body)
What is the function f the ciliary body
hold lens in place and change convexity of lens
What composes the nervous layer of the eye
posterior 3/4 : retina, contains numerous receptors
anterior 1/4: epithelial layer loaded with melanin
-separated by the line ora serata
where does the anterior 1/4 of the nervous layer of the eye extend to
the back of the iris
What is the optic disc
exact exit point of the optic nerve and opthalmic artery , the artery is surrounded by the optic nerve.
has no photoreceptors
What is the macula lutea
has a high number of photoreceptors, and the fovea is the very center of the macula lutea
What is the fovea
highest concentration of cones
What is the function of the ciliary body
arranged in concentric layers ( like a sphincter) , when it contracts the diameter of the opening of the ciliary body - it becomes narrower , suspensory ligaments will be lose and the convexity increases, when the ciliary body relazes the convexity decreases
what happens when you have parasympathetic and sympathetic innervation of the ciliary body
sympathetic: see far, relax the ciliary body, causes flattening of lens
parasymp: see near, contract ciliary body
what are the 2 sets of muscles in the iris
circular and radial
what causes pupil to decrease / increase
decrease: ( parasympathetic), caused by circular muscle contraction
increase: ( sympathetic), caused by radial muscle contraction
What are the 3 chambers
- anterior chamber: cornea to iris
- posterior chamber: iris to lens
- vitreous chamber: lens to retina
What fluid fills the anterior and posterior chamber
ciliary body produces the aqueous humor
How does aqueous humor flow
made by ciliary body from the posterior chamber to the anterior chamber to the veins in the cornea and sclera junction
what does the aqueous humor do
nourishes the structure and removes waste material
what is the difference between glaucoma and cataracts
glaucoma: high pressure at cornea : build up of pressure
cornea: hardening of lens
What is the lacrimal apparatus
consists of lacrimal gland and ducts
Function of lacrimal gland
produces tears directed towards medial corner of the eye which contain ducts ( lacrimal canaliculi), drain tears into the larcrimal sac contained within lacrimal fossa of the larcrimal bone
What is the nasolacrimal duct
It is the distal contunuation of the lacrimal sac that empties into the inferior nasal meatus- through parasympathetic fibers
