The human body consists of a circulatory system that transports blood and oxygen throughout the body via arteries, arterioles, capillaries and veins. Blood is composed of blood cells suspended in plasma and performs vital functions like delivering oxygen and nutrients to tissues via the smallest blood vessels, capillaries. The components of blood that support these functions include plasma, red blood cells that carry oxygen, platelets that control bleeding, and white blood cells that fight infection.

1. The human bodyBy Bianca Egger

2. ArteriesArteries are the vessels that carry blood and oxygen fromyour heart to the rest of your body. Arterioles continue to branch into smaller and smaller vessels which, once they have decreasedin size below 10 micrometresin diameter are known ascapillaries.

3. Veinsveins are blood vessels that carry blood towardsthe heart.Most veins carry deoxygenated blood from the tissues back to the heart.

4. BloodBlood is a specialized bodily fluid that deliversnecessary substances to the body's cells.In vertebrates, it is composed of blood cellssuspended in a liquid called blood plasma.

5. CapillariesCapillaries are the smallest of a body's blood vessels and areparts of the microcirculation.They are only 1 cell thick. They connect arterioles andvenules, and enable the exchange of water, oxygen, carbon dioxide, and many other nutrient and waste chemical substances between blood and surrounding tissues.

6. Components of blood

7. PlasmaBlood plasma is theyellow liquid component of blood in which the blood cells in whole blood are normally suspended.It makes up about 55% of the total blood volume.

8. Red blood CellsRed blood cells are the most common type of blood cell and the vertebrate organism's principal means of delivering oxygen to the body tissues via the blood flow through the circulatory system. They take up oxygen in the lungs and release it while squeezing through the body's capillaries.

9. PlateletsPlatelets, "clot" the blood from rushing out of your body whenyou cut yourself. They are small, regularly shaped clear cell fragments.The average lifespan of a platelet is normally just 5 to 9 days.

10. White blood cellsWhite blood cells, are cells of the immune system involved in defending the body against both infectious disease and foreign materials.