Question

3.  What is a sarcomere? What are striations, and why does skeletal muscle have a striated appearance? (1 pt)

4. Are cardiac muscle cells unbranched (like skeletal muscle cells) or branched? Are they multi-nucleated (like skeletal muscle) or with single nuclei? (1 pt)

5. Are smooth muscle cells long and fibrous (like skeletal muscle cells) or much shorter and compact? Are they multi-nucleated or with single nuclei? (1 pt)

Answer 1

3. Sarcomere is the contractile unit of a striated muscle fiber. Sarcomeres are divided into bands of filaments made of actin or myosin. It is the structures coming between the two z lines. Striated appearance is due to the formtion of alternative light or I band by thin filament and Dark bands comprising of thick filaments.

4.Cardiac muscle cells are branched unlike the skeletal muscle cells. They are multi-nucleated (like skeletal muscle).

5. smooth muscle cells short and compact unlike skeletal muscle cells. They are with single nuclei.