Which types of muscle tissue are striated when viewed under a microscope?

• A. Smooth muscle only
• B. Skeletal muscle and cardiac muscle
• C. Cardiac muscle and smooth muscle
• D. Skeletal muscle and smooth muscle

Answer: (B)

Verified step by step guidance

1. Understand the three types of muscle tissue: skeletal, cardiac, and smooth muscle.
2. Recall that striations are alternating light and dark bands seen under a microscope, caused by the organized arrangement of actin and myosin filaments in muscle fibers.
3. Identify that skeletal muscle is striated because it has a highly organized structure of sarcomeres, which produce the banding pattern.
4. Recognize that cardiac muscle is also striated due to a similar sarcomere arrangement, although its cells are branched and connected by intercalated discs.
5. Note that smooth muscle lacks striations because its actin and myosin filaments are arranged more randomly, so it appears smooth under the microscope.