CHAPTER 11, 12, 13

• Functions of blood


  • Transport of gases, nutrients and waste products
  • Transport of processed molecules
  • Transport of regulatory molecules
  • Regulation of pH and osmosis
  • Maintenance of body temperature
  • Protection against foreign substances
  • Clot formation
• Components of blood


  • Albumin
  • Globulin
  • Fibrinogen
• Hematopoesis


  1. In fetus, hematopoesis happens in various tissues such as the liver, thymus, spleen, lymph nodes, and red bone marrow

  2. After birth, erythrocytes are produced in bone marrow while some leukocytes are produced in the lymphatic system
• Erythrocytes


  • Primary function is to transport oxygen to the tissues
  • Biconcave disk without nucleus
  • Live for 120 days in males and 110 days in females
• Hemoglobin


  • Makes up 1/3 of the RBC's volume; a pigmented protein which is responsible for the cell's red color
  • Each globin protein is attached to a heme molecule that contains one iron molecule
  • Oxygen binds to iron forming oxyhemoglobin
• Production of erythrocytes


  1. Erythropoietin - hormone produced by the kidney that stimulates the production of RBC in red bone marrow

  2. Some athletes use an illegal drug 'erythropoietin' to increase their RBC

  3. To increase RBC count: increase fluid intake, eat food rich in iron (liver) and leafy vegetables, take iron supplements such as ferrous sulfate
• Fate of old erythrocytes and hemoglobin

  1. Old RBCs are removed from the blood by macrophages in spleen and liver

  2. When hemoglobin is broken down, globin turns into amino acids and iron is recycled, while heme is converted in bilirubin which is transported to the liver and secreted to the small intestine as part of bile
• Leukocytes


  • Have nucleus and larger than RBCs; however, they lack hemoglobin
  • Defend against disease by recognizing proteins that do not belong to the body
  • Able to ooze (pseudopodia) through the walls of capillaries to patrol the tissues and reach the lymph system
  • Capture pathogens through phagocytosis
  • In CBC, when WBC count is low it means that they are fighting an infection somewhere in the body. WBC uses negative feedback mechanism in fighting diseases
• Types of leukocytes


  • Granulocytes (Neutrophil, Basophil, Eosinophil)
  • Agranulocytes (Lymphocyte, Monocyte)
• Neutrophils


  • Nucleus with two four lobes connected by thin filaments, cytoplasmic granules stain a light pink or reddish purple
  • Most common
  • Remain in blood for 10 to 12 hours then move to tissues
  • Phagocytes
• Basophils


  • Nucleus with two indistinct lobes; cytoplasmic granules stain blue purple
  • Least common
  • Release histamine and heparin
• Eosinophils


  • Nucleus often bilobed, cytoplasmic granules stain orange red or bright red
  • Reduce inflammation
  • Destroy parasites
• Lymphocytes


  • Round nucleus, cytoplasm forms a thin ring around the nucleus
  • Immune response
  • Several different types (T cells and B cells)
  • Lead to produce antibodies
• Monocytes


  • Nucleus round, kidney-shaped, or horseshoe-shaped; contains more cytoplasm than lymphocyte
  • Largest and produce macrophages
• Thrombocytes


  • Cell fragment surrounded by a plasma membrane containing granules
  • Produced in the red bone marrow from large cells called megakaryocytes
  • Small fragments break off from the megakaryocytes and enter the blood as platelets
  • Necessary in preventing blood loss
• Preventing blood loss


  1. Vascular spasm - immediate but temporary constriction of blood vessel when the smooth muscle within the wall of the vessel contracts

  2. Platelet plug formation - series of steps including platelet adhesion, activation, and aggregation

  3. Blood clotting (coagulation)
• Blood clotting


  1. Damage in blood vessel activates the clotting factors caused by exposed tissues or release of thromboplastin

  2. Clotting factor (prothrombinase) is formed and acts upon prothrombin

  3. Prothrombin turns into thrombin (active form)

  4. Thrombin activates fibrinogen into fibrin

  5. Fibrin forms a network that traps blood (clots)
• Clot formation control


  • Anticoagulants - prevent clots from forming e.g., heparin and antithrombin
  • Anticoagulants can't work on a specific area of the body that experienced injury since it causes enough clotting factors to be activated
• Clot retraction


  1. Process where blood clot shrinks which enhances healing

  2. Occurs within 24 hours of initial clot formation
• Fibrinolysis


  1. Process of dissolving blood clot

  2. Occurs after clot retraction

  3. Prevents naturally occurring blood clots to grow and caused problems

  4. Plasma protein (plasminogen) breaks down blood clot (fibrin)
• Agglutination


  Transfusion reaction; clumping of blood cells
• Antigens


  Molecules on the RBC's surface; foreign substances that causes the immune system to produce antibodies
• Antibodies


  Protein in the plasma that was produced by the immune system to fight and attack specific antigens
• Blood groups


  Named according to antigen (ABO)
• ABO blood groupings


  • Type A blood plasma
  • Type B blood plasma
  • Type AB blood plasma
  • Type O blood plasma
• Type A can receive type A and O blood
• Type B can receive type B and O blood
• Type AB is universal receiver
• Type O is universal donor but can only receive type O blood
• Rh blood groupings


  • Rh+ have Rh antigens
  • 85% to 95% of the population is Rh+
  • When Rh- individual is exposed to Rh+ blood they develop antibodies, its either from transfusion or pregnancy
• Rh incompatibility in pregnancy


  During pregnancy, Rh antibodies from the mother's body can cross the placenta and attacks the fetal blood cells
• Hemolytic anemia


  • A serious type of anemia in the fetus in which RBC's are destroyed faster rather than being replaced
  • Could be fatal
  • Prevented through RhoGAM which contains antibodies against Rh antigens
• Complications may include: brain damage due to high levels of bilirubin (kernicterus) fluid buildup and swelling in the baby (hydrops fetalis) problems with mental function, movement, hearing, speech, and seizures
• Prothrombin time - time it takes for blood to clot (9 - 12 secs)
• WBC count - total number of WBC
• Leukopenia


  Low WBC count caused by radiation, chemotherapy drugs, tumors, and viral infections
• Leukocytosis


  High WBC count caused by infection and leukemia
• If type AB is universal receiver and type O is universal donor why does one can't receive blood from another? In blood transfusion, everything is being transferred including the antibodies and antigen. Transferring type AB to type O or vice versa might cause agglutination, so both plasma and blood transfusion must be matched to avoid an immune reaction.
• Blood


  Liquid connective tissue that consists of cells surrounded by liquid extracellular matrix
• Components of blood


  • Plasma
  • Formed elements