What is a cell?

The basic unit in our body is the cell.  Our bodies have about 100 trillion cells.  All cells perform basic metabolic functions like using oxygen and consuming food.  Cells have certain components, some of the important ones are:

  1. Cell wall – outer protective layer
  2. Nucleus – contains the chromosomes, DNA and genetic material
  3. Mitochondria – the “furnace” that makes food into chemical energy the cell can use
  4. Cytoplasm – the liquid material filling the cell
  5. Ribosomes – the factory that produces proteins that make up the cell and allow it to function

 definition of a cell

There are over 100 different types of cells.  Each of these types performs special functions.  For instance, heart muscle cells are designed to pump regularly, lung cells allow us to breathe and red blood cells carry oxygen.  Groups of cells make up tissues and organs, more on those later.  It is these groups of cells working together that make all of our bodily functions possible.

Some types of cells like blood cells and skin cells produce new cells constantly.  Other types of cells like nerve cells or heart cells make very few or no new cells.  The job of making new cells is the job of stem cells, no matter what types of cells we are talking about.  So if you cut your skin, stem cells make the new cells to heal the wound.  If you break a bone, special bone stem cells make new bone.  This will become very important later on when we talk about adult stem cell therapy.