Histology Testbank: Connective Tissue 1a

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 NOT primarily composed of connective tissue?
a. Blood
b. Bone
c. Tendon
d. Intervertebral disc
e. Myometrium

Answer: e

Of the four basic tissue types (epithelium, connective tissue, muscle and nervous tissue), connective tissue is the most diverse. Blood, bone, tendon, and intervertebral discs are all composed of connective tissue. The myometrium is the muscular layer of the uterus. Thus, the myometrium is composed of muscle tissue.

2.
Which of the following is NOT a fiber found in connective tissue?
a. Collagen fiber
b. Elastic fiber
c. Reticular fiber
d. Purkinje fiber
e. All of the above are fibers found in connective tissue

Answer: d

There are three types of fibers found in connective tissue: collagen fibers, elastic fibers, and reticular fibers. Collagen fibers are the most abundant fiber type in connective tissue.

Purkinje fibers are seen in the heart. Purkinje fibers are specialized muscle fibers.

3.
Which connective tissue cell type contains properties of smooth muscle cells?
a. Fibroblast
b. Myofibroblast
c. Histiocyte
d. Plasma cell
e. Mast cell

Answer: b

Myofibroblasts contain properties of both fibroblasts and smooth muscle cells.

Fibroblasts, histiocytes, plasma cells, and mast cells are routinely seen in loose connective tissue. Fibroblasts produce collagen. The fibroblast also produces the ground substance in connective tissue. Myofibroblasts contain properties of both fibroblasts and smooth muscle cells. The histiocyte is a connective tissue macrophage. Plasma cells are derived from B lymphocytes. Mast cells secrete histamine. Mast cells also secrete heparin, SRS-A (slow reacting substance of anaphylaxis, ECF-A (eosinophilic chemotactic factor of anaphylaxis.

4.
Which cell is a connective tissue macrophage?
a. Kupffer cells
b. Histiocyte
c. Dust cell
d. Langerhans cell
e. Microglia

Answer: b

Macrophages are mononuclear phagocytes. Many tissues have resident (fixed) macrophages. Fixed macrophages are given a unique name, depending on the tissue that they are located in. Kupffer cells are the hepatic macrophages. Histiocytes are macrophages seen in connective tissue. Dust cells are alveolar macrophage found in the respiratory tract. Langerhans cells are macrophages seen in the skin. Microglia are the central nervous system macrophages.

5.
Which of the following can be classified as "specialized connective tissue"?
a. Mesenchyme
b. Mucous connective tissue
c. Dense connective tissue
d. Blood
e. Loose connective tissue

Answer: d

Connective tissue can be sub-classified into connective tissue proper, specialized connective tissue and embryonic connective tissue.

Connective tissue proper consists of loose irregular connective tissue and dense connective tissue (regular and irregular).

Specialized connective tissue includes cartilage, bone, adipose tissue, blood and hemopoietic tissue, and lymphatic tissue.

Embryonic connective tissue includes mesenchyme and mucous connective tissue.

6.
Which of the following can be classified as "embryonic connective tissue"?
a. Cartilage
b. Mucous connective tissue
d. Adipose tissue
d. Bone
e. Blood

Answer: b

Connective tissue can be sub-classified into connective tissue proper, specialized connective tissue and embryonic connective tissue.

Connective tissue proper consists of loose irregular connective tissue and dense connective tissue (regular and irregular).

Specialized connective tissue includes cartilage, bone, adipose tissue, blood and hemopoietic tissue, and lymphatic tissue.

Embryonic connective tissue includes mesenchyme and mucous connective tissue.

7.
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.

8.
What type of adipose tissue tends to increase as humans age?
a. Brown adipose tissue
b. White adipose tissue
c. Unilocular adipose tissue
d. Multilocular adipose tissue
e. Both b and c

Answer: e

Brown adipose tissue is multilocular adipose tissue. This is present during fetal development and then decreases after birth.

White adipose tissue is unilocular adipose tissue. This type of tissue persists into adulthood.

9.
Which of the following would be best suited to differentiate collagen fibers from other fibers?
a. Wright's stain
b. Hematoxylin and eosin stain
c. Sudan stain
d. Silver impregnation
e. Masson's trichrome stain

Answer: e

A peripheral blood smear would be best visualized with Wright's stain. Hematoxylin and eosin stain is the most commonly used tissue stain for routine histological examination. Lipids are best displayed with a sudan stain. Silver impregnation, such as with a reticular stain, can be used to visualize reticular fibers. Collagen fibers can be differentiated from other fibers by staining with Masson's trichrome stain.