Correct Option
The correct option isSmooth muscle
Explanation
Animal tissues are classified based on their structure and function. Muscle tissues, specifically, are categorized into three types: skeletal (striated), smooth (non-striated), and cardiac. The shape of the muscle fibers (cells) is a primary morphological distinction among these types.
Option Analysis
- Striated muscle Striated muscle (Skeletal muscle): Incorrect. These muscle fibers are long, cylindrical, unbranched, and multinucleate. They do not taper at the ends.
- Smooth muscle Smooth muscle: Correct. The cells of smooth muscle tissue are long and pointed at both ends. This shape is technically described as fusiform or spindle-shaped. They are uninucleate and lack striations. These tissues are typically found in the walls of internal organs such as blood vessels, the stomach, and the intestine.
- Cardiac muscle Cardiac muscle: Incorrect. Cardiac muscle cells are cylindrical, branched, and uninucleate. They are structurally distinct from the spindle shape of smooth muscles.
- Nervous tissue Nervous tissue: Incorrect. Nervous tissue consists of neurons and neuroglia. Neurons typically possess a cell body (cyton) with elongated projections (axons and dendrites), resulting in an irregular or star-like shape rather than a spindle shape.
Key Takeaway
Smooth muscle fibers are uniquely characterized by their spindle-shaped (fusiform) structure and lack of striations, distinguishing them from the cylindrical forms of skeletal and cardiac muscles.