Histology Testbank: Special Senses 3a

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.
During the American Revolution, in the battle of Bunker Hill, an officer instructed his troops: "Don't fire until you see the whites of their eyes". What anatomical structure was he referring to?
a. Choroid
b. Ciliary body
c. Iris
d. Ora serrata
e. Sclera

Answer: e

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".

2.
Where is the region associated with maximum visual acuity?
a. Ciliary body
b. Optic disc
c. Fovea centralis
d. Lamina vitrea
e. Lamina cribrosa

Answer: c

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.

3.
What is the suspensory ligament of the lens?
a. Zonlular fibers
b. Purkinje fibers
c. Elastic fibers
d. Spiral ligament
e. Oval ligament

Answer: a

The zonular fibers are the suspensory ligament of the lens.

4.
Which layer of the cornea is acellular?
a. Bowman's membrane
b. Substantia propria
c. Epithelium
d. Endothelium
e. All of the above

Answer: a

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.

5.
How many layers of tissue compose the eyeball?
a. 1
b. 2
c. 3
d. 4
e. 5

Answer: c

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.

6.
What type of glands are the glands of Moll?
a. Endocrine gland
b. Apocrine sweat gland
c. Oil gland
d. Sebaceous glands
e. Eccrine sweat gland

Answer: b

The glands of Moll in the eyelid are apocrine sweat glands.

7.
Which structure is part the uvea?
a. Ora serrata
b. Pigmented epithelium
c. Cornea
d. Sclera
e. Ciliary body

Answer: e

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

8.
What is the space anterior 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: d

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.

9.
What is the vascular pigmented structure?
a. Choroid
b. Ciliary body
c. Iris
d. Ora serrata
e. Lens

Answer: a

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".

10.
What type of epithelium is on the surface of the cornea?
a. Simple squamous
b. Stratified squamous
c. Simple cuboidal
d. Simple columnar
e. Transitional epithelium

Answer: b

The surface of the cornea is covered by a non keratinized stratified squamous epithelium.