How Much Do You Know About Skeletal Muscle? Trivia Quiz

Smooth muscle and cardiac muscle are both types of muscle tissue that are involuntary, meaning they are not under conscious control. Smooth muscle is found in the walls of organs such as the stomach, intestines, and blood vessels, and it helps to regulate their movements. Cardiac muscle is found in the heart and is responsible for pumping blood throughout the body. Both of these muscle types are controlled by the autonomic nervous system, which operates without conscious effort. Therefore, the statement that smooth muscle and cardiac muscle are involuntary is true.

A tendon is a tough, fibrous connective tissue that attaches muscle to bone. It is responsible for transmitting the force generated by the muscle to the bone, allowing movement to occur. Tendons are composed of collagen fibers that are highly resistant to tension, providing strength and stability to the attachment point. Adipose tissue is a type of fat tissue, cartilage is a flexible connective tissue that provides support and cushioning, and ligaments attach bone to bone, providing stability to joints. Therefore, the correct answer is tendon.

The biceps brachii is a muscle located in the upper arm that is responsible for flexing the elbow joint. The triceps brachii, on the other hand, is a muscle located on the back of the upper arm that is responsible for extending the elbow joint. Since flexion and extension are opposite movements, the triceps brachii would be antagonistic to the biceps brachii.

The origin refers to the point of muscle attachment that remains fixed or stationary during muscle contraction. This means that the origin does not move, while the insertion (the other point of muscle attachment) is the one that moves towards the origin.

Smooth muscle tissue is not striated because it lacks the organized arrangement of actin and myosin filaments that give skeletal and cardiac muscle their striated appearance. Smooth muscle is found in the walls of hollow organs, blood vessels, and other structures, and its contraction is controlled involuntarily by the autonomic nervous system. Unlike skeletal and cardiac muscle, smooth muscle does not have a regular pattern of alternating light and dark bands, making it non-striated.

Myofibrils are the elongated bundles of contractile proteins that fill the cytoplasm of skeletal muscle fibers. These proteins, called actin and myosin, are responsible for the contraction and relaxation of muscles, allowing for movement and locomotion. Myofibrils play a crucial role in muscle function and are essential for muscle contraction.

Muscles that work in opposition to one another, such as the biceps brachii and the triceps brachii, are known as antagonists. Antagonist muscles have opposite actions and are responsible for controlling movement in opposite directions. In the case of the biceps and triceps, the biceps flexes the arm at the elbow joint while the triceps extends the arm. This antagonistic relationship allows for smooth and coordinated movement.

Smooth muscle is not cross-striated because myofibrils are not in register with each other. In cross-striated muscles, such as skeletal and cardiac muscles, the myofibrils are arranged in a highly organized manner and are aligned in parallel, resulting in the characteristic striations. However, in smooth muscle, the myofibrils are not aligned in a uniform pattern and do not have a regular arrangement. This lack of alignment and organization is why smooth muscle does not exhibit cross-striations.

Intercalated discs are specialized cell junctions found in cardiac muscle tissue. These discs help to connect individual cardiac muscle cells together, allowing for coordinated contraction of the heart. The intercalated discs are most likely to be observed in a longitudinal section of cardiac muscle because this section would show the alignment and arrangement of the cardiac muscle cells and the intercalated discs between them. The other options, such as transverse sections of skeletal muscle or cardiac muscle, would not provide a clear view of the intercalated discs.

The insertion is the point of muscle attachment that is synergistic. Synergistic refers to muscles that work together to produce a specific movement or stabilize a joint. In the context of muscle attachment, the insertion is the point where the muscle attaches to the bone and works in conjunction with other muscles to create coordinated movement.