Fundamentals of Anatomy and Physiology

Diagram of the human heart (labelled)

        Superior vena cava      Aorta (arch)
                 \             /   Pulmonary artery
                  \           /   /
                   \   _____ /   /       Pulmonary veins
                    \ /     V   V         /
   Pulmonary  ---->  |  RA  |  LA  | <----
   veins (right)     |      |      |
                     |------+------|
                     |Tricuspid|Bicuspid (mitral)
                     |  valve  |valve
                     |  RV  | |  LV  |
                     |      |S|      |
                      \     |e|     /
                       \    |p|    /
Inferior vena cava       \  |t|  /
   (enters RA from below)  \|u|/
                            \m/
                             V  Apex

Labels to show on the drawing: right atrium (RA), right ventricle (RV), left atrium (LA), left ventricle (LV); superior and inferior vena cava entering the right atrium; pulmonary artery leaving the right ventricle; pulmonary veins entering the left atrium; aorta leaving the left ventricle; tricuspid valve (RA-RV); bicuspid/mitral valve (LA-LV); semilunar (pulmonary and aortic) valves; interventricular septum; myocardium; apex.

The right side carries deoxygenated blood to the lungs, and the left side carries oxygenated blood to the body.

Functions of the circulatory system

The circulatory system consists of the heart, blood vessels and blood.

1. Transport of oxygen from the lungs to all tissues, carried by haemoglobin in red blood cells.
2. Removal of carbon dioxide and wastes such as urea, carried to the lungs and kidneys for excretion.
3. Transport of nutrients (glucose, amino acids, fats, vitamins, minerals) from the intestine to the cells.
4. Transport of hormones from endocrine glands to target organs.
5. Regulation of body temperature by distributing heat through the body.
6. Defence against infection, by white blood cells and antibodies.
7. Clotting and fluid balance: platelets and plasma proteins stop blood loss, and plasma maintains water and electrolyte balance.