Q.Define tetany and state its immediate cause.

Muscular disorders: Myasthenia gravis (autoimmune blocking of acetylcholine receptors at the neuromuscular junction, causing progressive weakness); Tetany (muscle spasms from parathyroid-hormone deficiency and low blood calcium); Muscle fatigue (inability to keep contracting, from ATP shortage and lactic-acid build-up); Atrophy (muscle wasting from disuse); Muscle pull (a traumatic tear from overstretching, e.g. causing back pain); Muscular dystrophy (progressive genetic degeneration of muscle fibres, e.g. Duchenne Muscular Dystrophy); and Rigor mortis (post-mortem stiffening, as ATP depletion after death leaves actin-myosin cross-bridges permanently locked). …