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## Blood Platelets Blood platelets are amorphous just like WBCs. They are not real cells, but fragments of the stem cell in the red bone marrow. They cannot be seen even in fresh blood samples, as they disintegrate upon contact with air. This is their important attribute - as platelets disintegra...

## Blood Platelets Blood platelets are amorphous just like WBCs. They are not real cells, but fragments of the stem cell in the red bone marrow. They cannot be seen even in fresh blood samples, as they disintegrate upon contact with air. This is their important attribute - as platelets disintegrate, the blood-clotting process begins. ## Skills Lab: Observing Human Blood Cells ### Safety Tips - Observe the proper way of focusing the specimen using the microscope. - Handle the microscope properly and with care when getting it from and returning it to the cabinet. - Be careful in handling breakable materials. - Dispose of waste materials properly. - Wash your hands often. ### Observing Human Blood Cells 1. Get a prepared slide of the human blood smear from the lab technician. 2. Focus the prepared slide under the High Power Objective (HPO) of the compound microscope. Choose a part in the field of view where several blood cells are seen. Observe the blood cells. 3. In your science notebook, draw the different blood cells that you can see in the field of view. You can shift the field of view to see more cells. Observe the structures of the cells, particularly the shape of the nuclei of the white blood cells. ## ABO Blood Relationships In 1900, Karl Landsteiner, an Austrian scientist at the University of Vienna, discovered four different blood groups that characterize human populations. These blood types are A, B, AB, and O, where, in most cases, the specific combination of these four components determines an individual's blood type. Landsteiner was awarded the Nobel Prize in Medicine in 1930 for his work. | Blood Type | Antigen | Antibody | |---|---|---| | A | A | B | | B | B | A | | AB | A and B | None | | O | None | A and B | **Figure 1.9. The variations in the human blood group components** - A blood type A person has antigen A in the red blood cells, and antibody B in the plasma. - A blood type B person has antigen B in the red blood cells, and antibody A in the plasma. - A blood type AB person has both antigens A and B in the red blood cells and no A or B antibodies in the plasma. - A blood type O person has neither A nor B antigens in the red blood cells, but has both A and B antibodies in the plasma.