Which of the following descriptions characterizes skeletal muscle tissue?
a. It contains striations.
b. It contains uninucleate cells.
c. It contains spindle-shaped cells.
d. It contains intercalated discs.
e. It contains branched cells.
The correct answer and explanation is :
The correct answer is:
a. It contains striations.
Explanation:
Skeletal muscle tissue is one of the three main types of muscle tissue in the human body, alongside cardiac muscle and smooth muscle. It has several unique characteristics that distinguish it from the other two types.
- Striations (Correct Choice)
Skeletal muscle fibers are characterized by a striped, or striated, appearance under a microscope. These striations result from the highly organized arrangement of actin and myosin filaments within the muscle fibers, which form repeating units called sarcomeres. This structure allows skeletal muscle to contract efficiently and generate movement. - Multinucleated Cells (Not b)
Unlike cardiac or smooth muscle, skeletal muscle fibers are multinucleated. This is because they are formed by the fusion of multiple embryonic cells called myoblasts during development. Therefore, option b (It contains uninucleate cells) is incorrect. - Cylindrical Shape (Not c, Not e)
Skeletal muscle cells are long, cylindrical, and unbranched. In contrast, smooth muscle cells are spindle-shaped (option c) and cardiac muscle cells are branched (option e). Hence, both options c and e are incorrect. - No Intercalated Discs (Not d)
Intercalated discs are specialized junctions found only in cardiac muscle tissue. They allow electrical impulses to spread rapidly between cardiac muscle cells, enabling coordinated heart contractions. Since skeletal muscle does not have intercalated discs, option d is incorrect.
Summary
Skeletal muscle tissue is characterized by striations, multinucleated cells, and cylindrical shape. It is voluntary muscle, meaning it is consciously controlled, unlike cardiac and smooth muscles, which function involuntarily. Its striations, caused by sarcomeres, make option (a) the correct answer.