Red blood cell
Red blood cells (also known as RBCs, red blood corpuscles or erythrocytes) are cells in the blood which transport oxygen. Red blood cells are very large in number; in women, there are 4.8 million red blood cells per microliter of blood. In men, there are 5.4 million red blood cells per microliter of blood. Red blood cells are red because they have haemoglobin in them.
The most important function of red blood cells is the transport of oxygen. The haemoglobin absorbs oxygen in the lungs, travels through blood vessels and brings oxygen to all other cells via the heart. Since the blood cells go through both the lungs (to collect oxygen), through the heart (to be pumped around the rest of the body to give all cells oxygen) and back to the heart to be re-pumped to the lungs (to again collect oxygen), it is said that the blood in your body travels in a double circuit, going through your heart twice before it completes one full of the body.
A fact which makes human red blood cells different to all other cells is that, when they are mature, red blood cells do not have a nucleus. However, most other vertebrates have red cells with nuclei.
Red blood cells are doughnut (without the hole) shaped. This shape is called a Bi-concave disc. However, hereditary diseases such as sickle-cell disease can cause them to change shapes and stop blood flow in capillaries and veins. Plasma is obtained from whole blood. To prevent clotting, an anticoagulant such as citrate is added to the blood specimen immediately after it is obtained
- Bradfield, Phil; Potter, Steve (2009). Edexcel IGCSE Biology Student Book. Pearson Education. ISBN 9780435966881.
- Liang, Barbara. "General Anatomy & Physiology: Red Blood Cells". Wisc-Online. http://www.wisc-online.com/objects/ViewObject.aspx?ID=ap14604. Retrieved 2011-03-22.