Histology Testbank: Special Senses 5a

Instructions: For each histology question, pick the one best answer. This histology test bank is also useful for the histology questions on the USMLE (USMLE step 1).

Where on the retina are there no photoreceptors?
a. Ciliary body
b. Optic disc
c. Fovea centralis
d. Lamina vitrea
e. Lamina cribrosa

Answer: b

The ciliary body is a thickening in the uvea. It contains the ciliary muscle.

The site where the optic nerve leaves the eyeball is the optic disc. This region is also called the anatomical blind spot. Since there are no photoreceptors at this spot, it causes a blind spot in the visual field.

The fovea centralis is part of the retina. There are only cone cells in the fovea centralis. It is the site for maximal visual acuity.

The inner layer of the choroid is the lamina vitrea. The lamina vitrea is also referred to as Bruch's membrane.

The lamina cribrosa are small openings within the sclera where the fibers forming the optic nerve travel through.

What makes up the bulk of the sclera?
a. Purkinje fibers
b. Myofibrils
c. Elastic fibers
d. Reticular fibers
e. Collagen fibers

Answer: e

The sclera is composed primarily of collagen fibers.

Which is NOT part of the retina?
a. Rods
b. Cones
c. Bipolar cells
d. Ganglion cells
e. Uvea

Answer: e

The eyeball has three layers. The innermost layer is the retina. The middle layer is the uvea. The outer layer is the sclera and cornea.

The retina consists of the rods, cones, bipolar cells, ganglion cells, horizontal cells, and amacrine cells. The receptors for vision are the rods and cones. The rods are located on the periphery, and are not color sensitive. The cones are the receptors for color.

What is the most anterior portion of the uvea?
a. Choroid
b. Ciliary body
c. Iris
d. Ora serrata
e. Sclera

Answer: c

The vascular pigmented structure of the uvea is the choroid. The ciliary body contains the ciliary muscle. The ciliary muscle is responsible for adjusting the lens. The most anterior portion of the uvea is the iris. The anterior pigmented portion of the retina is called the ora serrata. The sclera is the "white of the eye".

Which one of the following is not found in the retina?
a. Pigment epithelium
b. Muller's cells
c. Huxley's layer
d. Horizontal cells
e. Cones

Answer: c

Pigment epithelium, Muller's cells, horizontal cells, and cones cells are all part of the retina.

Huxley's layer is a layer in the hair follicle.

Which structure is part the uvea?
a. Sclera
b. Iris
c. Ora serrata
d. Pigmented epithelium
e. Cornea

Answer: b

The uvea is the middle layer of the eyeball. It consists of the iris, choroid and ciliary body.

What is the space posterior to the iris?
a. Anterior chamber
b. Posterior chamber
c. Vitreal cavity
d. Both a and b
e. All of a, b, and c

Answer: b

The region behind the lens is the vitreal cavity. The chambers anterior to the lens are the anterior chamber and posterior chamber. The iris separates the anterior chamber from the posterior chamber.