An organelle is a specialized cellular structure in eukaryotic cells analogous to an organ in the body.Organelles are discrete structures within the cell that perform a specialized function. Most are surrounded by internal membranes and can be seen in the light or the electron microscope.n organelle is a specialized cellular structure in eukaryotic cells analogous to an organ in the body.
irregular pulse or heart palpitations; chest pain; pale skin; sweating; What causes abnormal heart rhythms? A number of things may cause an abnormal heartbeat, including high blood pressure. Other common causes are: Coronary heart disease. This serious heart problem occurs when cholesterol and other deposits block the coronary arteries. Medications
Certain substances can contribute to an abnormal/irregular heartbeat, including: 1  Caffeine. 2  Tobacco. 3  Alcohol. 4  Cold and cough medications. 5  Appetite suppressants. 6  Psychotropic drugs (used to treat certain mental illnesses) 7  Antiarrhythmics (paradoxically, the same drugs used to treat arrhythmia can also cause arrhythmia.