Which description best fits a longitudinal section of smooth muscle?

Which description best fits a longitudinal section of smooth muscle?

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

Answer: (D)

In a longitudinal section of smooth muscle you’ll see elongated fusiform (spindle-shaped) cells aligned in parallel. These cells have a single central nucleus and lack visible striations, which distinguishes smooth muscle from skeletal or cardiac muscle. Intercalated discs are specific to cardiac muscle, and striations are due to sarcomeres seen in skeletal and cardiac muscle, not smooth. The description parallel bundles of spindle-shaped cells captures both the shape of the cells and their orderly, lengthwise arrangement, which is exactly what a longitudinal view of smooth muscle shows.

In a longitudinal section of smooth muscle you’ll see elongated fusiform (spindle-shaped) cells aligned in parallel. These cells have a single central nucleus and lack visible striations, which distinguishes smooth muscle from skeletal or cardiac muscle. Intercalated discs are specific to cardiac muscle, and striations are due to sarcomeres seen in skeletal and cardiac muscle, not smooth. The description parallel bundles of spindle-shaped cells captures both the shape of the cells and their orderly, lengthwise arrangement, which is exactly what a longitudinal view of smooth muscle shows.