| A | B |
|---|
| heart | a muscular pump which circulates blood throughout the body that is divided into four chambers |
| auricles or atria | the two upper and smaller chambers of the heart |
| ventricles | the two lower chambers of the heart |
| septum | a muscular wall that separates the right side from the left side of the heart |
| valves | separate the auricles from the ventricles and keep blood from flowing in the wrong direction |
| Oxygen-poor (blue) blood | comes back to the heart from the body cells collects in the right auricle then it is forced into the left ventricle. From here it is pumped through another valve on its way to the lungs. |
| In the lungs | carbon dioxide is exchanged for oxygen |
| Oxygen-rich (red) blood | returns to the heart gfrom the lungs and collects in the left auricle then it is pumped to the left ventricle and pumped through another valve to the main arteries of the body. |
| The arteries distribute blood to | capillarieswhich in turn convey it directly to the body cells |
| In the cells oxygen from the blood is used for | internal respiration |
| Internal Respiration | the chemical processes by which oxygen is used to burn or oxidize food thereby producing energy |
| The left ventricle | is the most muscular chamber vecause it has to pump the blood through all the vessels of the body except those to and from the lungs |
| The heart is tilted | slightly to the left |
| The number of heartbeats per minute | is controlled by the nervous system |
| Systemic circulation | the process by pumping blood from the heart to the body cells and back again |
| Pulmonary circulation | the process of pumping blood from the heart to the lungs and back again |
