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
How stress leads to a strain on the heart. By FIONA MACRAE, science reporter. Last updated at 23:53 09 April 2007. Stress could be responsible for many heart problems, researchers say. Their findings could help explain what triggers irregular heartbeats, which can lead to heart attacks and sudden death. A study of brain activity in those with heart conditions revealed that the cortex - a region associated with learning, memory and emotion - controls the heart during times of stress.