Definition of an Organ
Groups of tissues located and working together make up an organ. Organs perform specific, typically vital functions. Some of the organs you are familiar with are the heart, lungs, brain, liver, kidneys and stomach. There are many others in our bodies.
To see how an organ has several different tissues, we can take a closer look at the heart. The heart is made up of the muscular tissue we know. But it is also made up of electrical conducting tissue and specialized tissue that makes up the “cardiac skeleton”. The electrical tissue conducts the impulse that causes the muscles to contract and the heart to pump. These electrical impulses are what we see on an EKG. The cardiac skeleton provides a structure for the muscle to pump against much as our bones provide a stable structure for your muscles to pull against. The heart valves are also part of the cardiac skeleton. So the heart requires each of the tissues to work properly. Each tissue requires its cells to be working properly. This is true of all of our organs. When injured or diseased, cells, tissues and organs use growth factors to call on stem cells for repair.