A longitudinal section of smooth muscle is best described by which feature?

A longitudinal section of smooth muscle is best described by which feature?

• A. Circular profiles
• B. Striations
• C. Parallel bundles of spindle-shaped cells
• D. Multinucleated cells

Answer: (C)

Smooth muscle cells are slender and spindle-shaped (fusiform) and tend to run in parallel bundles in a given layer. In a longitudinal section, this arrangement stands out as long, parallel, elongated cells that align with one another, which is why the description of parallel bundles of spindle-shaped cells is the best match. Notice that smooth muscle lacks obvious striations, so you wouldn’t describe it as having a striped appearance like skeletal muscle. Also, smooth muscle cells are typically uninucleate, not multinucleated, which helps distinguish it from skeletal muscle. In a circular layer, you’d more likely see circular profiles in a cross-section, which isn’t the feature shown in a longitudinal view.

Smooth muscle cells are slender and spindle-shaped (fusiform) and tend to run in parallel bundles in a given layer. In a longitudinal section, this arrangement stands out as long, parallel, elongated cells that align with one another, which is why the description of parallel bundles of spindle-shaped cells is the best match.

Notice that smooth muscle lacks obvious striations, so you wouldn’t describe it as having a striped appearance like skeletal muscle. Also, smooth muscle cells are typically uninucleate, not multinucleated, which helps distinguish it from skeletal muscle. In a circular layer, you’d more likely see circular profiles in a cross-section, which isn’t the feature shown in a longitudinal view.