Histology Testbank: Special Senses 4a

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).

1.
What structure was Crystal Gayle referring to when she sang, "Don't it make my brown eyes blue"?
a. Pupil
b. Lens
c. Cornea
d. Iris
e. Retina

Answer: d

The iris is the colored part of the eyes.

2.
What makes up the bulk of the cornea?
a. Purkinje fibers
b. Myofibrils
c. Elastic fibers
d. Reticular fibers
e. Collagen fibers

Answer: e

The cornea is composed primarily of collagen fibers.

3.
What is the middle layer of the eyeball?
a. Uvea
b. Rods
c. Cones
d. Bipolar cells
e. Ganglion cells

Answer: a

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.

4.
What is the anterior pigmented portion of the retina called?
a. Choroid
b. Ciliary body
c. Iris
d. Ora serrata
e. Sclera

Answer: d

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".

5.
Which one of the following is not found in the retina?
a. Henle's layer
b. Bipolar cells
c. Amacrine cells
d. Rods
e. Ganglion cells

Answer: a

Bipolar cells, amacrine cells, rods, and ganglion cells are all part of the retina.

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

6.
Which structure is part the uvea?
a. Ora serrata
b. Pigmented epithelium
c. Choroid
d. Cornea
e. Sclera

Answer: c

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

7.
What is the space posterior to the lens?
a. Anterior chamber
b. Posterior chamber
c. Vitreal cavity
d. Both a and b
e. All of a, b, and c

Answer: c

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.

8.
Where is the blind spot?
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.

9.
How many layers does the retina have?
a. 1
b. 2
c. 4
d. 5
e. 10

Answer: e

There are ten layers to the retina.

10.
Which of the following is NOT a layer of the cornea?
a. Bowman's membrane
b. Substantia propria
c. Descemet's membrane
d. Lamina vitrea
e. Endothelium

Answer: d

There are five layers to the cornea: epithelium, Bowman's membrane, substantia propria, Descemet's membrane, and endothelium.

The surface of the cornea is covered by a non keratinized stratified squamous epithelium. Bowman's membrane and Descemet's membrane are acellular. The majority of the cornea is from the substantia propria. The endothelium is a simple epithelium.

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