Blood
Oxygen is carried by red blood cells. Glucose is dissolved in the liquid part of the blood, called plasma. Plasma leaks out of the capillaries and forms tissue fluid around cells in the body. Some of the oxygen leaves the red blood cells dissolves in the tissue fluid. The red blood cells stay inside the capillary.
If you press two fingers firmly onto your wrist, you can feel your blood being pumped. This is called your pulse. Your pulse rate is the number of beats you can feel in one minute.
