Histology Testbank: Skin 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).

1.
The papillary layer is part of which layer?
a. Epidermis
b. Dermis
c. Hypodermis
d. Both a and b
e. None of the above

Answer: b

The skin is composed of two layers: the epidermis and the dermis. Underneath these layers lies the hypodermis. The epidermis is stratified squamous epithelium. The dermis is composed of a papillary layer and a reticular layer. The reticular layer of the dermis is made up of dense irregular connective tissue. The hypodermis is a layer of loose connective tissue.

2.
Which layer of the epidermis contains star shaped cells?
a. Stratum basale
b. Stratum spinosum
c. Stratum granulosum
d. Stratum lucidum
e. Stratum corneum

Answer: b

The epidermis is divided into five layers: stratum basale, stratum spinosum, stratum granulosum, stratum lucidum, and stratum corneum.

The stratum basale contains the dividing cells. This layer is also called the stratum germinativum.

The stratum spinosum consists of a layer several cells deep. The cells have pointy or spiny processes on them. The cells in the stratum granulosum contain keratohyaline granules.

The stratum lucidum is present only in thick skin.

The stratum corneum is the outermost layer. The cells in this layer are essentially bags of keratin. They contain no nuclei or organelles.

Note from Sarah Bellham: My favorite mnemonic for remembering the layers of the skin: "Californian Ladies Give Superb Backrubs"

3.
Which of the following layers comprise the skin?
a. Epidermis
b. Dermis
c. Hypodermis
d. Both a and b
e. Both b and c

Answer: d

The skin is composed of two layers: the epidermis and the dermis. Underneath these layers lies the hypodermis. The epidermis is stratified squamous epithelium. The dermis is composed of a papillary layer and a reticular layer. The reticular layer of the dermis is made up of dense irregular connective tissue. The hypodermis is a layer of loose connective tissue.

4.
Which cell is responsible for skin pigmentation?
a. Langerhans cell
b. Keratinocyte
c. Melanocyte
d. Merkel cell
e. Fibroblast

Answer: c

Langerhans cells, keratinocytes, melanocytes, and Merkel cells are all found in the epidermis. The Langerhans cell is a phagocyte. The keratinocyte is the most abundant cell in the epidermis. The melanocyte produces melanin, which is responsible for skin pigmentation. The Merkel cell is a mechanoreceptor.

Fibroblasts are found in the dermis. Fibroblasts produces collagen.

5.
Which of the following responds to pain?
a. Free nerve endings
b. Ruffini's corpuscles
c. Pacinian corpuscles
d. Krause's end bulbs
e. Meissner's corpuscle

Answer: a

There are several different sensory receptors in the skin. The most abundant sensory receptor are the free nerve endings. Free nerve endings respond to pain and temperature. Ruffini's corpuscles respond to continuous pressure. Pacinian corpuscles respond to vibration and rapidly changing pressure. Krause's end bulbs are a receptor for fine touch which are located in mucous membranes and the tongue. Meissner's corpuscles are also a receptor for fine touch but they are located in the dermis.

6.
What is the correct term for cuticle?
a. Lunula
b. Eponychium
c. Matrix
d. Nail bed
e. Root

Answer: b

The lunula is the half moon shaped white area on a nail. The anatomical term for the cuticle is the eponychium. The matrix is the region of the nails where there are dividing cells and nail growth. The nail plate rests on the nail bed. The nail root is the proximal portion of the nail that is underneath skin.

7.
What color is keratin with Masson's trichrome stain?
a. Red
b. Pink
c. Green
d. Black
e. Yellow

Answer: a

A trichrome stain is a mixture of three dyes. Collagen fibers stain green with Masson's trichrome stain. Muscle and keratin will be red with Masson's trichrome stain. Cytoplasm will be pink. Nuclei will be black.

8.
What type of tissue makes up the dermis of the skin?
a. Mucous connective tissue
b. Mesenchyme
c. Loose irregular connective tissue
d. Dense irregular connective tissue
e. Dense regular connective tissue

Answer: d

Mesenchyme is embryonic connective tissue. It is an undifferentiated tissue found in the embryo. Mucous connective tissue is a type of embryonic connective tissue; it is a subset of mesenchyme. Wharton's jelly is mucous connective tissue. Loose irregular connective tissue is areolar tissue. Dense irregular connective tissue is seen in the dermis. Dense regular connective tissue comprises tendons and ligaments.

9.
What are the pressure receptors in skin called?
a. Psammoma bodies
b. Corpora arenacea
c. Hassall's corpuscles
d. Prostatic concretions
e. Pacinian corpuscles

Answer: e

Psammoma bodies are collections of calcium. It is derived from the Greek word "psammos", which means sand.

Corpora arenacea refers to the calcifications seen in the pineal gland. Corpora arenacea is nicknamed "brain sand".

Hassall's corpuscles are the ring like structures found in the thymus.

The spherical structures seen in some prostatic alveoli are called prostatic concretions.

Pacinian corpuscles are pressure receptors in the skin.

10.
Which sensory receptor in the skin is NOT encapsulated?
a. Ruffini endings
b. Free nerve endings
c. Pacinian corpuscles
d. Meissner's corpuscles
e. Merkel cells

Answer: b

Ruffini endings, pacinian corpuscles, meissner's corpuscles, and merkel cells are all encapsulated sensory receptors. Free nerve endings are not encapsulated.