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Bell Work. How would you describe blood? Does lower or higher density materials float? What does proximal mean? Where is the epiphysis of the femur located? What is a clot? What is blood plasma?. Blood. The only fluid tissue in our body
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Bell Work • How would you describe blood? • Does lower or higher density materials float? • What does proximal mean? • Where is the epiphysis of the femur located? • What is a clot? • What is blood plasma?
Blood • The only fluid tissue in our body • It transports everything that is needed in our bodies • It has formed elements (living blood cells) and plasma (nonliving fluid matrix)
Hematopoiesis • Blood Cell Formation • Occurs in the Red Bone Marrow or myeloid found chiefly in the flat bones of the skull and pelvis, the ribs, sternum, and the proximalepiphyses of the humerus and femur. • All blood cells arise from a common type of stem cell called the hemocytoblast, but triggers will cause the stem cells to irreversibly change to produce the different types of blood cells
Separating Blood • Blood can be separated using a centrifuge, which uses a fast rotational motion to separate components based on densities. • Materials with high densities would sink to the bottom while lower densities would remain at the top.
At the top, you would have… • Plasma, which is composed of • Mostly water (90%) • Salts • Plama Proteins • Nutrients • Waste • Respiratory Gases • Hormones
At the bottom, you would have… Erythrocytes
Erythrocytes • Red blood cells • Outnumber other parts by roughly 1000 to 1 • Transport oxygen and carbondioxide • They do not have a nucleus and have very few organelles • Basically, they are a sac full of the iron-bearing protein called hemoglobin • One cell can contain 250 hemoglobin molecules, each of which can bind 4 oxygen molecules
In the middle, the buffy coat, which contains… Leukocytes Platelets
Leukocytes • White blood cells • Defense and immunity • Can perform • Diapedesis – can leave and enter the blood stream • Positive chemotaxis – they can travel around the body in response to chemicals that are released from damaged cells. They follow the diffusion gradient of these chemicals to find the injured area. • Leukocytosis – when the body makes more WBC • Leukopenia – abnormally low levels of WBC
Types • Granulocytes – contain granules • Neutrophils –phagocytes at sites of acute infection • Eosinophils – helps battle allergies and infections by parasitic worms • Basophils – contain large histomine (inflammatory chemical) containing granules • Agranulocytes • Lymphocytes – Found in lymphatic tissue and plays an important role in immune response • Monocytes – Largest WBC that migrates into tissues, turn into macrophages, which can destroy large amounts of infection.
Platelets • Irregular cell fragments that originate from megakaryocytes • Used for blood clotting when hemostasis occurs
What is hemostasis? • A stoppage of blood flow through broken blood vessels • Steps in hemostasis. • Plateletplugformation – “sticky” platelets cling to damage area and use a chemical to attract more platelets • Vascularspasms – serotonin is also released by platelets. This causes the blood vessel to spasm and narrow, which decreases blood loss • Coagulation (bloodclotting) occurs
Coagulation Steps • Injured tissue releases tissuefactor • A chemical, PF3, on the surface of the platelets reacts with the tissuefactor and some other ions to form an activator (prothrombin) that starts the clottingcascade. • The activator converts prothrombin into thrombin • The thrombin joins fibrinogen in the area into long, insoluble, hair like molecules called fibrin. This creates a mesh that traps RBC and forms the clot. • Once the clotting cascade starts, factors are triggered to stop widespread clotting