Summative Practice 14 – Question 10 (Form 4 Biology Textbook Exercise and Answer)

Question 10:
(a) Explain the property of muscles involved in human movement.

(b) (i) Explain the measures that can be practised to maintain a healthy musculoskeletal system.
(b)(ii) Describe the factors that may put an individual at a high risk of developing osteoporosis.

(c) Describe how muscles work together with the ligament and tendon to move the forearm.

• The muscles involved in movement is skeletal muscles. Skeletal muscles produce a voluntary response because they are controlled by the nervous system and can be stimulated under conscious control.

• Skeletal muscles provide the force that is needed to move bones at the joints.

• Skeletal muscles are unable to push or stretch but can contract and relax.

• Contraction shortens the skeletal muscle.

• Relaxation returns the muscle to its original shape and size.

• The intake of balanced nutrition, for example, taking calcium supplement, phosphate, vitamin A, C and D. Vitamin D aids in calcium absorption and vitamin C increases bone mass.

• Wear comfortable and loose attire.

• Avoid wearing high-heeled shoes.

• Exercise and participate in sports regularly.

• Practise correct and safe exercise techniques to prevent injury to the musculoskeletal system.

• Always adopt good posture in all daily activities.

• Age factor: as a person ages, the density of the bone decreases and subsequently, the bone mass decreases.

• Lack of oestrogen: osteoporosis is more common in menopausal women because the oestrogen level drops after menopause. Oestrogen is involved in calcium metabolism; helps the body absorb calcium and reduce its loss.

• Lack of exercise: exercise stimulates calcium sedimentation

• Lack of calcium intake in the diet

Bending the arm
• At the shoulder, the tendon from one end of the biceps is attached to the scapula (fixed bone) while at the elbows, the tendon at the other end of the biceps is attached to the radius (free-moving bone).

• The tendon from one end of the triceps is attached to the end of the scapula while the tendon on the other end is attached to the ulna.

• When bending the arm, the pulling force produced is transmitted to the bone through the tendon. The contraction of the biceps causes the radius to be pulled upwards and the arm is bent.

• At the same time, the triceps relaxes.

Straightening the arm
• The triceps contracts causing the ulna to be pulled down and the arm is straightened.

• At the same time, the biceps relaxes.

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