Chapter 6 - Connective Tissue

Question 1

Which one of the following statements regarding collagen is true?
(A) It is composed of tropocollagen.
(B) Reticular fibers are composed of type II
collagen.
(C) It is synthesized mostly by mast cells.
(D) Elastic fibers are composed of type IV
collagen.
(E) Type II collagen is most common in connective tissue proper.

Answer 1

A. Collagen is composed of closely packed tropocollagen molecules. Reticular fibers are composed of type III collagen, whereas elastic fibers are composed of elastin microfibrils rather than collagen. Fibrocytes are inactive nonsecreting fibroblasts that synthesize the procollagen molecules (see Chapter 6 II B 1).

Question 2

Dense regular connective tissue is present in
(A) capsules of organs.
(B) basement membrane.
(C) tendons.
(D) skin.
(E) dermis.

Answer 2

C. Tendons are composed of dense regular connective tissue containing collagen fibers arranged in a uniform parallel fashion (see Chapter 6 IV B 2).

Question 3

Of the following cell types found in connective tissue, which is most often present along capillaries and resembles fibroblasts?
(A) Plasma cell
(B) Lymphocyte
(C) Macrophage
(D) Mast cell
(E) Pericyte

Answer 3

E. Pericytes are pluripotential cells that resemble fibroblasts, although they are smaller, and are adjacent to capillaries (see Chapter 6 III B).

Question 4

Synovial fluids of normal joints are usually devoid of collagen. Patients with rheumatoid diseases have various types of collagen in their synovial fluid, depending on the tissue being damaged. If a patient has type II collagen in the synovial joint, which of the following tissues is being eroded?
(A) Vascular endothelium
(B) Compact bone
(C) Vascular smooth muscle
(D) Articular cartilage
(E) Synovial membrane

Answer 4

D. Type II collagen is present only in hyaline and elastic cartilages; therefore, finding type II collagen in the synovial fluid of a joint indicates erosion of the articular cartilage (see Chapter 6 II B 1).

Question 5

Which one of the following cell types arises from monocytes?
(A) Plasma cells
(B) Fibroblasts
(C) Lymphocytes
(D) Macrophages
(E) Mast cells

Answer 5

D. Monocytes leave the bloodstream and migrate into the connective tissue, where they mature into functional macrophages (see Chapter 6 III E).

Question 6

Foreign body giant cells are formed by the coalescence of
(A) macrophages.
(B) lymphocytes.
(C) fibroblasts.
(D) adipose cells.
(E) plasma cells.

Answer 6

A. Foreign body giant cells result when macrophages coalesce (see Chapter 6 III E 3).

Question 7

Which one of the following cell types in the connective tissue arises from myeloid stem cells?
(A) Pericytes
(B) Eosinophils
(C) Fibroblasts
(D) Osteoblasts
(E) Adipocytes

Answer 7

B. Eosinophils arise from myeloid stem cells during hemopoiesis and migrate to sites of inflam­mation within the connective tissue. Pericytes, fibroblasts, osteoblasts, and adipocytes arise from undifferentiated mesenchymal cells (see Chapter 6 III H 2).

Question 8

Which of the following cell types is respon­sible for anaphylactic shock?
(A) Fibroblasts
(B) Eosinophils
(C) Pericytes
(D) Mast cells
(E) Macrophages

Answer 8

D. After first exposure to an allergen, plasma cells make IgE antibodies that bind to FceRI recep­tors on mast cells (and basophils), sensitizing them. At the second exposure, the allergen binds to IgE, initiating degranulation of mast cells and releasing several mediators that give rise to type I hypersensitivity reaction (see Chapter 6 III D 4).

Question 9

Which one of the following statements re­garding proteoglycans is true?
(A) They consist of a core of fibrous protein covalently bound to glycoproteins.
(B) They are attached to ribonucleic acid.
(C) They are binding sites for deoxyribonucleic
acid.
(D) They are composed of a protein core to which glycosaminoglycans are attached.
(E) They are the exclusive substance of the ECM along with collagen.

Answer 9

D. Proteoglycans consist of a protein core to which glycosaminoglycans are attached (see Chapter 6 II A).

Question 10

Which one of the following statements con­cerning loose connective tissue is true?
(A) It is less abundant than dense connective tissue.
(B) It has a lower proportion of cells to fibers than does dense connective tissue.
(C) It acts as a medium for exchange of nutrients and wastes between the blood and tissues.
(D) It provides structural support for organs.
(E) It consists of many fibers in which various
types of cells are embedded.

Answer 10

C. Both loose and dense connective tissues are composed of three elements: anamorphous ground substance, fibers, and various types of cells. The amorphous ground substance of loose connective tissue is the medium of exchange between the connective tissue cells and the blood­ stream (see Chapter 6 IV B 1).