Question 1: Describe the primary function of skeletal muscles in the human body.

Answer: Skeletal muscles are responsible for voluntary movements, maintaining posture, and stabilizing joints by contracting to produce movement.

Question 2: Name three major muscle groups involved in upper body movement and describe their functions.

Answer: The biceps brachii (flexes the elbow), the pectoralis major (adducts and rotates the arm), and the deltoid (lifts the arm sideways).

Question 3: Explain the difference between voluntary and involuntary muscles, providing an example of each.

Answer: Voluntary muscles are consciously controlled, such as skeletal muscles used for movement. Involuntary muscles operate automatically, like the cardiac muscle of the heart.

Question 4: Identify the muscle group that is primarily used during running and describe its role.

Answer: The quadriceps are primarily used during running; they extend the knee and help propel the body forward.

Question 5: Describe what happens to muscle fibers during muscle contraction.

Answer: Muscle fibers contract by the sliding filament mechanism, where actin and myosin filaments slide past each other, shortening the muscle and producing force.

Question 6: Sketch a simple diagram of a muscle fiber, labeling the key parts such as the myofibril, sarcomere, and nucleus.

Answer: A correct sketch would show elongated muscle fibers with multiple myofibrils running lengthwise, with labeled sarcomeres (the contractile units) and nuclei located on the periphery.

Question 7: List two ways regular exercise can strengthen muscles and improve muscular endurance.

Answer: Regular resistance training stimulates muscle growth, and sustained aerobic activities increase muscular endurance by improving the muscle's ability to sustain repeated contractions.

Question 8: Explain the concept of muscle fatigue and one common cause during exercise.

Answer: Muscle fatigue is the decline in muscle strength due to prolonged activity, often caused by the depletion of energy sources like glycogen or the accumulation of lactic acid.

Question 9: Describe how the muscular system works in conjunction with the skeletal system during movement.

Answer: Muscles attach to bones via tendons; when muscles contract, they pull on bones, creating movement at the joints. This collaboration enables voluntary movement and stability.

Question 10: Draw a simple side view of the human arm and indicate where the biceps and triceps muscles are located.

Answer: A correct drawing would depict the upper arm with the biceps located at the front (upper part of the arm), and the triceps at the back (posterior side), with clear labels.