Differentiate between Pectoral and Pelvic girdle.

An elderly woman slipped in the bathroom and had severe pain in her lower back. After X-ray examination doctors told her it is due to a slipped disc. What does that mean? How does it affect our health?

Explain sliding filament theory of muscle contraction with neat sketches.

How does a muscle shorten during its contraction and return to its original form during relaxation?

Discuss the role of Ca2+ ions in muscle contraction. Draw neat sketches to illustrate your answer.