| |
|
|
| |
|
|
|
What is blood?Blood is a mixture of cells and a watery liquid called plasma. Blood also contains other substances like nutrients, hormones, clotting agents, and waste products to be flushed out of the body. Blood cells come in three varieties: red blood cells, white blood cells, and platelets. White blood cells are the largest of the three types of cells and are responsible for fighting infections or germs. Red blood cells carry oxygen to the cells in your body and return to the lungs to flush out carbon dioxide. Platelets are the smallest of the cells, and their job is to form clots (scabs) in the blood to help stop bleeding. Plasma is a sticky fluid that is 95 percent water. The other 5 percent contains nutrients, proteins, and hormones. In short, blood carries oxygen and nutrients to all parts of the body and carries carbon dioxide and other waste products back to the lungs, kidneys, and liver for filtration and disposal. Blood helps fight against infection and heals wounds so we can stay healthy. Blood Cells Are Produced in Bone Marrow. Red cells, white cells, and platelets are made in the marrow of bones, especially the vertebrae, ribs, hips, skull, and sternum. These essential blood cells fight infection, carry oxygen, and help control bleeding. Plasma Carries Blood Cells. Plasma is a pale yellow mixture of water, proteins, and salts. One of the functions of plasma is to act as a carrier for blood cells, nutrients, enzymes, and hormones. Red Cells Deliver Oxygen. Red cells are disc-shaped cells containing hemoglobin, which enables the delivery of oxygen to all parts of the body. White Cells Defend the Body. White cells are the body's primary defense against infection. They can move out of the blood stream and reach tissues being invaded by bacteria, viruses, and other substances. Platelets Help Control Bleeding. Platelets are small cells in the blood that control bleeding. They form clusters to plug small holes in blood vessels and are essential to the clotting process. There is no substitute for human blood. If people lose blood from surgery or injury, or if their bodies cannot produce enough new blood, there is only one place to turn—volunteer blood donors. Want to know more about blood? Here are 56 Facts About Blood.
|
|
|
