Muscular System 2

What is the basic structural unit of skeletal muscle?

• Myofibril

• Sarcoplasm

• Muscle fiber (myofiber)

• Muscle cell

How are skeletal muscle fibers arranged?

• Skeletal muscle fibers are arranged in a spiral configuration.

• Skeletal muscle fibers are arranged in circular patterns.

• Skeletal muscle fibers are arranged in parallel bundles.

• Skeletal muscle fibers are arranged randomly throughout the muscle.

What is the primary function of cardiac muscle?

• To pump blood throughout the body.

• To absorb nutrients from the blood.

• To facilitate gas exchange in the lungs.

• To store energy for muscle contractions.

What unique feature distinguishes cardiac muscle from skeletal muscle?

• Presence of myofibrils and multinucleation.

• Striated fibers and voluntary contraction.

• Slow contraction speed and rhythmicity.

• Intercalated discs and involuntary contraction.

What are the characteristics of smooth muscle?

• Characteristics of smooth muscle include being non-striated, involuntary, controlled by the autonomic nervous system, and having slow contraction and relaxation cycles.

• Controlled by the somatic nervous system

• Striated and voluntary

• Fast contraction and relaxation cycles

How does smooth muscle differ from skeletal muscle in terms of control?

• Smooth muscle is striated; skeletal muscle is non-striated.

• Smooth muscle is involuntary; skeletal muscle is voluntary.

• Smooth muscle is controlled by the somatic nervous system; skeletal muscle is controlled by the autonomic nervous system.

• Smooth muscle contracts faster than skeletal muscle; skeletal muscle contracts slower.

What is the role of calcium ions in muscle contraction?

• Calcium ions facilitate muscle contraction by enabling the interaction between actin and myosin.

• Calcium ions inhibit muscle contraction by blocking actin and myosin interaction.

• Calcium ions are only involved in nerve signal transmission, not muscle contraction.

• Calcium ions are stored in the muscle fibers and do not play a role in contraction.

Describe the sliding filament theory of muscle contraction.

• Muscle contraction occurs through the thickening of muscle fibers.

• The sliding filament theory describes how muscle contraction occurs through the sliding of actin and myosin filaments past each other.

• Actin and myosin filaments detach completely during contraction.

• Muscle contraction is solely dependent on calcium ions without filament interaction.

What is the main energy source for muscle contraction?

• Creatine phosphate

• Lactic acid

• Glucose

• Adenosine triphosphate (ATP)

How do skeletal muscles attach to bones?

• Skeletal muscles attach to bones through tendons.

• Skeletal muscles attach to bones through synovial fluid.

• Skeletal muscles are connected to bones by ligaments.

• Skeletal muscles attach directly to cartilage.