The Eye Outer, Middle, and inner 1/22/26

What's the function of the cornea? is it transparent and vascularized?

The function of the cornea is to refract light, it is transparent, but it is not vascularized, its avascular

Where is the stroma? what is it composed of?

It is located between the inner and outer epithelium of the cornea; it is composed of dense collagen fibers and

What is the conjunctiva? what are the two types?

It is a thin mucous membrane, with numerous goblet cells, that is behind the eyelid, there two types are bulbar conjunctiva and palpebral conjunctiva

Where is the bulbar conjunctiva?

It covers the anterior part of the sclera, and stops at the cornea

Where is the palpebral conjunctiva?

it covers the inner surface of both upper and lower eyelids

What is the function of conjunctiva? what type of epithelium is it?

Its numerous goblet cells lubricate the eyes and protect it from debris and infection, and it is non-keratinized stratified epithelium

what is conjunctivitis? what is its nickname?

Also known as pink eye, it is an infection of the conjunctiva from bacteria or viral infection

What are the three components of the middle layer of the eye?

choroid, ciliary body, iris

What is the choroid? how does impact light in the eye?

It is a membrane that lies underneath the sclera surrounding the eye, it is heavily pigmentated which allows it to absorb light and reflection which can affect vision

What is the ciliary body? what is its function?

It is ring of smooth muscle that's attached to the lens and connects the choroid to the iris, it functions to change the shape of the lens through suspensory ligaments for better vision and produce aqueous humor

What is the iris? what is its function?

it is a colored flat ring-shaped membrane behind the cornea with an opening in the middle called the pupil, it functions to receive light through the pupil and regulate it through the iris

What are the two groups of smooth muscle in the iris?

The sphincter pupillae, and the dilator pupillae

What is the function of the sphincter pupillae? what nerve innervates it?

It constricts the pupil and is innervated by the parasympathetic III cranial nerve

What is the function of the dilator pupillae? does it receive less or more ligh?

It dilates the pupil in response to sympathetic stimulation. it receives more light

What is visual accommodation?

The ability to change the thickness of the lens by thickening when objects get closer than 20ft and loosening objects are beyond that range

what are suspensory ligaments?

they are strings that attach the ciliary body to the lens that tighten and relax to change the shape of the lens

what composed inner eye? what are its two components?

The retina, it contains a pigmented outer layer and a neural inner layer

Where is the pigmented outer layer of the retina? what does it do?

It is between the choroid and the retina, it contains many melanin granules which help to absorb light and reduce random reflections

What are the three neural components of the retina?

The outer layer facing the choroid are photoreceptors, the middle layer are bipolar neurons, and the inner layer are ganglion cells

what is the flow of light through the 3 neural layers of the eye? what is the flow for images to processed?

ganglions, bipolar cells, photoreceptors. the wave of light returns in the opposite direction and sent to the optic nerve to be processed

What comprises the photoreceptor layer? what are each of their functions?

Rods and cones, rods respond in dim light, have low visual acuity, and are mostly peripheral. cones respond to bright light, have high visual acuity, and are mostly in fovea

what is the function of bipolar cells?

They transfer information between the ganglions and photoreceptor cells

What is the function of ganglionic cells in the retina?

They transmit information from light to the optic nerve through their axons

What is another name for the posterior back surface of the eye? what is contained here?

the fundus of the eye, it contains the optic disc, and the Macula, and fovea centralis

What is the optic disc? Are there blood vessels, photoreceptors and arteries here?

also known as the Blind spot, it is where optic nerve exits the eye. there are blood vessels and arteries but no photoreceptors

What is the macula? (Lots of cones) where is it?

It is a small yellow pigment on the posterior retina, surrounding the fovea centralis, responsible for central vision and visual acuity

What is the fovea centralis? (lots of rods) How is it identified?

it is located in the middle of the macula; it is the area in the retina with the greatest visual acuity containing only cones.

As you steer out of the macula what type of photoreceptor cells will you see more of?

rods, for peripheral vision

What is macular degeneration?

A vision change that can gradually increases blurry vision over time