Same chapter3 marksDifficulty: Medium
Name three disorders of the muscular and skeletal system and state the cause of each.
Locomotion and Movement
3 marksDifficulty: Medium
Explain the sliding filament theory of muscle contraction.
Original Khojo Papers practice question — not from a past board paper.
Answer
On stimulation, calcium ions released from the sarcoplasmic reticulum bind to troponin and expose the binding sites on actin. The myosin heads attach to actin, forming cross bridges, and swivel, pulling the actin filaments over the myosin towards the centre of the sarcomere. ATP then detaches the heads and the cycle repeats. The filaments themselves do not shorten; they slide past one another, so the sarcomere and hence the muscle shortens.
No citable source has been recorded for this record. Treat it as practice material, not as fact.
Explanation
The A band stays the same length while the I band and the H zone narrow.
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