Tell me more about blood and stem cells
What does blood do?
Blood has three main functions:
1. Transportation: Blood transports lots of substances around the body. It carries oxygen from the lungs, nutrients from the gut, and hormones from the glands, to the tissues in the body. It also carries waste products away.
2. Regulation: Blood helps the body to balance its internal environment, such as the maintenance of a constant temperature.
3. Protection against infection and blood loss: Blood contains infection-fighting cells and can clot to prevent excessive loss.
What is blood and how is it made?
Blood is a mixture of liquid and lots of tiny cells and proteins, which are made in different places in the body. The liquid part of blood is called plasma and is made up mostly of water and proteins. Carried in the plasma are three main types of cells and cell fragments: red blood cells, white blood cells and platelets.
Red blood cells: Red blood cells are red, iron containing cells which transport oxygen.
White blood cells: White blood cells have many different functions and for this reason, exist in lots of different specialist types. One particular white blood cell, the megakaryocyte, grows very large and then breaks up to make platelets. The megakaryocyte actually lives in the bone marrow until it breaks into platelets, which then enter the bloodstream.
Platelets: Platelets are tiny cell fragments which stick together and help blood to clot. The levels of all important markers and cells in the blood can be measured from a blood sample. Normally, your platelet count should be between 150 and 450 x 109/L. In ET, the platelet count is over 600 x 109/L.
Blood cells do not live forever. They are constantly being made by the body, and old ones are constantly being removed. However, in ET, too many platelets are made and they cannot be removed quickly enough by the body. This leads to a build-up of platelets in the blood.
What do blood vessels do and how does ET affect them?
Blood vessels contain your blood as it is pumped around your body. Veins and arteries are types of blood vessel. Arteries carry blood away from the heart and veins carry blood back to the heart. When you cut yourself and start to bleed, this is because one of your blood vessels has been damaged. Normally, this damage would be a signal for your platelets to come and stick to the damaged blood vessel wall, and to each other, to help to form a clot and stop the bleeding. However, in ET, the increased number of platelets in the blood means that they may form a clot in a normal blood vessel and block the flow of blood through to parts of the body.