This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Muscle, Subject name: Physiology
In malignant hypehermia, excess heat production is due to: 
Select and explain. 
A. Increased muscle metabolism by excess of calcium ions, B. Thermic effect of food, C. Increased sympathetic discharge, D. Mitochondrial thermogenesis
A: Increased muscle metabolism by excess of calcium ions
Answer: A: Increased muscle metabolism by excess of calcium ions 
Explanation: Malignant hypehermia is an autosomal-dominant disease in which the defect is in RyR1 gene. When such individuals are administered inhalation anaesthetics (halothane or ether) or muscle relaxant succinylcholine , there is excess release of Ca++ in the sarcoplasm. This increases muscle metabolism.