Vertebrate striated muscle contraction is controlled (regulated) by the action of the proteins troponin and tropomyosin on the actin filaments. Nervous stimulation causes a depolarisation of the muscle membrane (sarcolemma) which triggers the release of calcium ions from the sarcoplasmic reticulum.
n. 1  Abnormally fast or deep respiration, which results in the loss of carbon dioxide from the blood, thereby causing a fall in blood pressure, tingling of the extremities, and sometimes fainting.
Medical Definition of Breathing. Breathing: The process of respiration, during which air is inhaled into the lungs through the mouth or nose due to muscle contraction and then exhaled due to muscle relaxation. Last Editorial Review: 5/13/2016.