Histology Testbank: Skin 2a

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.
Which of the following is composed of connective tissue?
a. Epidermis
b. Dermis
c. Hypodermis
d. Both a and b
e. Both b and c

Answer: e

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 of the following is composed of dense irregular connective tissue?
a. Epidermis
b. Reticular layer of dermis
c. Hypodermis
d. Both a and b
e. Both b and c

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.

3.
Where is thick skin found?
a. Lips
b. Over the knee
c. Palms
d. Breast
e. All of the above

Answer: c

Thick skin is found on the palms of the hand and the sole of the feet. Thin skin
is found everywhere else.

4.
Which layer of the epidermis is present only in thick skin?
a. Stratum basale
b. Stratum spinosum
c. Stratum granulosum
d. Stratum lucidum
e. Stratum corneum

Answer: d

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"

5.
Which cell is a mechanoreceptors?
a. Langerhans cell
b. Keratinocyte
c. Melanocyte
d. Merkel cell
e. Fibroblast

Answer: d

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.

6.
Which cell is found in the dermis?
a. Langerhans cell
b. Keratinocyte
c. Melanocyte
d. Merkel cell
e. Fibroblast

Answer: e

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.

7.
What is underneath the nail plate?
a. Lunula
b. Eponychium
c. Matrix
d. Nail bed
e. Root

Answer: d

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.

8.
What is the innervation of an eccrine sweat gland?
a. Cholinergic; parasympathetic
b. Cholinergic; sympathetic
c. Adrenergic; parasympathetic
d. Adrenergic; sympathetic
e. Cholinergic; motor

Answer: b

Eccrine sweat glands are innervated by the sympathetic nervous system. The neurotransmitter for the eccrine sweat glands is acetylcholine. Thus it is cholinergic.

Note from Sarah Bellham: For most postganglionic sympathetic neurons, the neurotransmitter is norepinephrine. Eccrine sweat glands are an exception to this generalization, as the innervation for eccrine sweat glands is cholinergic sympathetic.

9.
Which of the following responds to continuous pressure?
a. Free nerve endings
b. Ruffini's corpuscles
c. Pacinian corpuscles
d. Krause's end bulbs
e. Meissner's corpuscle

Answer: b

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.

10.
Which of the following is found in the hair follicle?
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 are all part of the retina.

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