A type of muscle cell, found in certain fishes (e.g. sailfish and marlin), that is specialized for generation of heat. Heater cells lack muscle fibrils but retain the sarcoplasmic reticulum. When the cell is stimulated, stored calcium ions are released from the sarcoplasmic reticulum into the cytosol, triggering intense energy metabolism by mitochondria. This releases energy, in the form of heat, at rates of up to 250 W/kg.
Subjects: Biological Sciences.