Glossary M

Glossary M

Myocardial infarction refers to death of a portion of heart tissue that no longer conducts electrical activity nor provides force to move blood. Please see also MI. Myocardial infarction is also known as Angina pectoris or Cardiac arrest. Chest pain is a common symptom.

Myocardial ischemia is defined as a condition in which the myocardium experiences an inadequate blood flow; sometimes accompanied by irregularities in the electrocardiogram (Arrhythmias and ST-segment depression) and chest pain (Angina pectoris).

Myocardium is the cardiac or heart muscle that provides the force of contraction to eject blood; muscle type with many mitochondria that is dependent on a constant supply of oxygen.

Myoclonic seizures are seizures that manifest in arrhythmic bursts of jerky motor movements that usually do not last more than a second and tend to occur in clusters over a short period.

Myoclonus refers to a neurologic movement disorder characterized by brief, involuntary, twitching or "shock-like" contractions of a muscle or muscle group. These jerk-like movements may be accompanied by periodic, unexpected interruptions in voluntary muscle contraction, leading to lapses of sustained posture (known as "negative myoclonus").

Myoclonus index refers to the number of leg jerks per hour of sleep.

Myofibrils refers to the portion of the muscle containing the thick and thin contractile filaments; a series of sarcomeres where the repeating pattern of the contractile proteins gives the striated appearance to skeletal muscle.

Myoglobin is protein in muscle that can bind oxygen and release it at low PO2 values. Myoglobin aids in diffusion of oxygen from capillary to mitochondria.