Flashcards in Med Neuro [Week 2] Deck (29):
The cornea contributes between ________ of the eyes total focusing power.
True or false: The cornea has no blood vessels.
From outside to inside, what are the 5 layers of the cornea?
2. Bowman's Membrane
4. Descemet's Membrane
What is the function of the epithelium of the cornea? (2)
1. Protection from dust, water, and bacteria
2. Absorb oxygen and nutrients from tears and distribute them to the rest of the cornea.
What part of the cornea will scar as it heals?
Stroma consists primarily of water and collagen and contributes ______ of the cornea's thickness.
What is the function of Descemet's membrane?
Barrier against infection and injury
What is the function of the corneal endothelium?
1. Pump excess fluid out of the stroma
Can corneal endothelial cells regenerate?
No. Too much damage can lead to corneal edema and blindness
Nearsightedness (eye too long)
Farsightedness (eye too short)
What are the three parts of the uvea?
2. Ciliary body
What makes up the largest component of the uvea?
What are the three layers of the choroid?
1. Vessel layer - medium sized arteries and veins
2. Chorocapillary layer - capillaries arranged in one plane
3. Bruch's membrane - thin amorphous hyaline membrane where the retinal pigmented epithelia rests
What is the ciliary body?
An expansion of stroma of the choroid near the lens
What are the functions of the ciliary body?
2. Aqueous humor production
3. Production and maintenance of lens zonules
What is the function of the iris?
1. Cover the lens
2. Regulate amount of light reaching retina
People with brown eyes have more ____________.
What two muscles are behind the iris and regulate its size?
Sphincter pupillae - parasym
Dilator pupillae - symp
Aqueous humor is drained from the anterior chamber via the ________________. From here it passes into the _______________________ that drains to the venous system
1. Trabecular meshwork
2. Canal of Schlemm
Anterior of iris. Contains the aqueous humor, is avascular. Is involved in maintaining intraocular pressure
What is the most common form of glaucoma?
Open-angle or chronic glaucoma - due to an obstruction of the drainage system
What are the functions of the lens?
1. Refractive functions
2. Accommodation - thinner on distant objects - relaxed ciliary muscles
The vitreous body is nearly acellular, major macromolecules are ____________________ and ___________________.
1. Type 2 collagen
2. Hyaluronic acid
Where do the two regions of the retina come from?
Different layers of the optic cup during development
What are the two regions of the retina?
1. Neural/sensory retina
2. Retinal pigment epithelium
What are major functions of the retinal pigment epithelium?
1. Absorbs scattered light
2. Transports nutrients and ions between photoreceptors and choriocapillaries
3. Reisomerization of all-trans retinal
4. Secretion of GF for maintenance and structural integrity of retina
The retina has a dual blood supply from the __________________ and the ____________________.
1. Choriocapillaries - outer retina
2. Central retinal artery - inner retina