2.3 Explain the transport of oxygen and carbon dioxide by the blood.

Oxygen is inhaled into the lungs via breathing and together with haeoglobin found in red blood cells. The haemoglobin then transports the oxygen to cells that need it and releases it. Carbon dioxide is then picked up and carried back to the lungs where most of it is exhaled. Carbon dioxide diffuses from the tissues into red blood cells where it is combined with water to form carbonic acid.
Oxygen going into the lungs then diffuses into the blood stream through the pulmonary circulation and to the left side of the heart. Oxyhaemoglobin in as cellular respiration and energy is released or known as gas exchange. Carbon dioxide is released and diffuses into the blood stream and flows to the right side of the heart and through the lung and out into the atmosphere.
The aortic is between left ventricle and blood flows from the left ventricle to the aorta and to the whole body. Nodes are responsible for the heart beat and control the rhythmic sequence of contractions. They are called sino-atrial and artio ventricular.