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## Composition of Blood Blood, which is a liquid tissue, is the medium of circulation. Its main function is to transport materials and fight infection. The blood is composed of two parts: the liquid portion called plasma and the formed elements called corpuscles. ### The Different Formed Elements -...

## Composition of Blood Blood, which is a liquid tissue, is the medium of circulation. Its main function is to transport materials and fight infection. The blood is composed of two parts: the liquid portion called plasma and the formed elements called corpuscles. ### The Different Formed Elements - **Red blood cells (RBCs)** transport gases, especially oxygen, to all parts of the body. Structurally, RBCs are shaped like a biconcave disk and do not have a nucleus (anucleated). The red color is due to the pigment hemoglobin that also enables them to carry and transport oxygen. - **White blood cells (WBCs)** fight infection by producing antibodies and engulfing foreign bodies (phagocytes). Structurally, most of their shapes are irregular (amorphous), but they are nucleated. WBCs are of two types – those with granules in the cytoplasm (granulocytes) and those that lack granules in the cytoplasm (agranulocytes). They can also be identified using the shape of the nucleus as the basis. The granulocytes are the basophil, neutrophil, and eosinophil, named after the kind of stain they can absorb. The agranulocytes are the monocytes and the lymphocytes. - **Blood platelets** are among the smallest formed blood cells, they are just fragments of larger cells found in fresh blood samples because they disintegrate quickly. ### Skills Lab **Safety Tips** - Observe the proper way of using the microscope. - Handle the microscope properly. - Be careful in handling breakable materials. - Dispose of waste materials properly. - Wash your hands often. **Observing the different types of blood cells** - Get a prepared slide of human blood. - Focus the prepared slide under the microscope - Choose a part in the field of view where the cells are spread out. - In your science notebook draw and label the cells you observe. **ABO Blood Relationships** In 1900, Karl Landsteiner, an Austrian scientist, discovered blood groups that characterize human blood. In most cases, the specific combination of antigens and antibodies determines a person’s blood group. Landsteiner was awarded the Nobel Prize in 1930 for his work. - **A Blood Type** A person who has antigen A in the red blood cell and antibody B in the plasma is blood type A. - **B Blood Type** A person who has antigen B in the red blood cell and antibody A in the plasma is blood type B. - **AB Blood Type** A person who has both antigen A and antigen B in the red blood cell and no antibodies in the plasma is blood type AB. - **O Blood Type** A person who has neither antigen A nor B in the red blood cell and has antibody A and antibody B in the plasma is blood type O.