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
Common causes of abnormal heart rhythms (arrhythmias) or conditions that can lead to arrhythmias include: 1  Heart defects you're born with (congenital heart defects). 2  Coronary artery disease. 3  High blood pressure. 4  Diabetes. 5  Smoking.6  Excessive use of alcohol or caffeine. 7  Drug abuse. 8  Stress.eart infections, such as pericarditis, endocarditis and myocarditis, are caused when an irritant, such as a bacterium, virus or chemical, reaches your heart muscle. The most common causes of heart infections include: 1  Bacteria. 2  Viruses. 3  Parasites.