Video: Which Way Is Up?: How T Cells Adjust Their Orientation to Selectively Mount Immune Responses

A tissue with red blood cells, white blood cells, platelets, and other substances suspended in fluid called plasma. Blood takes oxygen and nutrients to the tissues, and carries away wastes.

The individual unit that makes up the tissues of the body. All living things are made up of one or more cells.

The activity of the immune system against foreign substances (antigens).