Anatomy of the Retina

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Questions and Answers

What is the main function of the choroid in the eye?

To provide a rich blood supply to the retina (correct)

To transmit light signals to the brain

To regulate the amount of light entering the eye

To absorb light and prevent it from scattering

What is the pathway of light through the retina?

Ganglion cells → bipolar cells → photoreceptors

Photoreceptors → ganglion cells → bipolar cells

Photoreceptors → bipolar cells → ganglion cells (correct)

Bipolar cells → photoreceptors → ganglion cells

Which type of photoreceptor is responsible for peripheral and night vision?

Bipolar cells

Rods (correct)

Ganglion cells

Cones

What percentage of all sensory receptors are found in the eyes?

70 percent Signup and view all the answers

How many nerve fibers are found in each eye?

Over 1 million nerve fibers Signup and view all the answers

Which structure is responsible for regulating the amount of light entering the eye?

Iris Signup and view all the answers

What is the primary function of the bony orbit?

To protect the eye Signup and view all the answers

What is the function of the pigmented layer in the retina?

To absorb light and prevent it from scattering Signup and view all the answers

What is the purpose of the conjunctiva?

To protect the eye Signup and view all the answers

What is the site where the conjunctiva merges with the cornea?

Eyelid Signup and view all the answers

What is the function of the ciliary body in the eye?

To attach the lens to the eye via the ciliary zonule Signup and view all the answers

What is the function of the lacrimal apparatus?

To produce tears Signup and view all the answers

What is the region of the retina that is lateral to the blind spot?

Area with only cones Signup and view all the answers

What is the name of the region where the eyelid meets the eye?

Palpebral fissure Signup and view all the answers

What is the function of the fovea centralis?

To provide the sharpest vision Signup and view all the answers

In which area of the retina are there no photoreceptor cells?

Optic disc Signup and view all the answers

What is the function of the extrinsic eye muscles?

To move the eye Signup and view all the answers

What is the location of the densest concentration of cones in the retina?

Center of the retina Signup and view all the answers

What is the function of the rods in the retina?

Allow vision in dim light and peripheral vision Signup and view all the answers

What is the purpose of the suspensory ligament in the eye?

To hold the lens in place Signup and view all the answers

What is the structure of the lens in the eye?

Biconvex crystal-like structure Signup and view all the answers

What is the purpose of the pigment layer in the retina?

To absorb light and prevent glare Signup and view all the answers

Study Notes

Structure of the Eye

The eye has a pigmented layer of retina, central artery, and vein of retina.
The optic disc is located at the back of the eye.
The sclera is the outer layer of the eye.
The optic nerve is connected to the eye.

Sensory Layer

The retina has two types of neurons: rods and cones.
Rods are found towards the edges of the retina, allow vision in dim light and peripheral vision, and perceive in gray tones.
Cones are densest in the center of the retina, allow for detailed color vision, and are found in the fovea centralis.
There are no photoreceptor cells at the optic disc, or blind spot.

Lens

The lens is a biconvex crystal-like structure held in place by a suspensory ligament attached to the ciliary body.

Special Senses

The five special senses are smell, taste, sight, hearing, and equilibrium.

The Eye and Vision

70 percent of all sensory receptors are in the eyes.
Each eye has over 1 million nerve fibers.
The eye is protected by a bony orbit and a cushion of fat.

Accessory Structures of the Eye

The accessory structures of the eye include eyelids and eyelashes, conjunctiva, lacrimal apparatus, and extrinsic eye muscles.

Surface Anatomy of the Eye and Accessory Structures

The conjunctiva merges with the cornea at the limbus.
The eyelids and eyelashes protect the eye.
The lacrimal caruncle is located at the medial commissure.

Vascular Layer

The choroid is a blood-rich nutritive layer in the posterior of the eye.
The choroid is modified anteriorly into two structures: ciliary body and iris.
The iris regulates the amount of light entering the eye and gives the eye its color.

Retina

The retina contains two layers: outer pigmented layer and inner neural layer.
The outer pigmented layer absorbs light and prevents it from scattering.
The inner neural layer contains receptor cells (photoreceptors) including rods and cones.