Medical Dictionary. arrhythmia. play. noun arÂ·rhythÂ·mia \Ä-Ërith-mÄ-É\. Medical Definition of arrhythmia. : an alteration in rhythm of the heartbeat either in time or force.
Central metabolism provides mechanisms for the generation of energy from carbon-energy source catabolism and the production of biosynthetic precursors and intermediates for the anabolic pathways essential to maintain cell structure and function.
The liver additionally produces glucose from non-carbohydrate sources other than fatty acids by a process called gluconeogenesis during starvation. In the brain, ketone bodies are a vital source of energy during fasting or strenuous exercise.