Bio 2

• Module 1 - Blood


  Introduction to the course
• Components of Blood


  • Plasma
  • Formed elements
• Functions of Blood


  • Transportation
  • Regulation
  • Protection
  • Communication
  • Maintain constant environment
  • Immune defense
  • Clotting
  • Carrying signal molecules
• Erythropoiesis


  1. In embryo: yolk sac, liver, and spleen

  2. After birth: almost exclusively by red bone marrow

  3. Regulated by the “erythropoietin (EPO)” hormone
• Erythropoietin Analogues


  • Epoetin alpha
  • Darbepoetin alpha
• Hemoglobin Molecule


  • Assembly of four globular proteins known as “Globins”
  • Each globin composed of a protein chain (alpha or beta)
  • Protein chains tightly linked to a “heme” group
• The average lifespan for RBC is 120 days then it is removed from the bloodstream
• Requirements for healthy erythrocytes

  • Erythropoietin
  • Iron for hemoglobin
  • Folic acid and vitamin B12 for replication and maturation
• Disease States


  • Hypoxemia: low oxygen level in the blood
  • Hypoxia: low oxygen level in the tissue
  • Cyanosis: blue coloration of the skin and mucous membranes due to the presence high level of deoxygenated hemoglobin in blood vessels near the skin surface
  • Causes of low oxygen in the blood: low oxygen intake, low oxygen carrying capacity, interrupted blood flow, others
• Erythrocytes count and indices

  • RBC count: M - 4.6-6.2 M/ml, F - 4.2-5.4 M/ml, Low count indicates iron deficiency, hemorrhage
• Causes of reduced RBC count

  • Iron deficiency, hemorrhage, bone marrow damage, kidney failure
• Causes of high RBC count

  • Hypoxia
• Causes of low Hemoglobin level

  • Iron deficiency anemia
• Causes of high Hemoglobin level

  • Smokers, high altitudes, dehydration
• Causes of low Hematocrit level


  • Hemorrhage
• Causes of high Hematocrit level

  • Hypoxia
• Causes of low Mean cell volume (MCV)

  • Microcytic anemia (iron deficiency)
• Causes of high Mean cell volume (MCV)

  • Macrocytic and pernicious anemia
• Sickle Cell Anemia is a genetic disease in which mutated beta chain produces hemoglobin S
• Sickle Cell Anemia


  1. Hemoglobin becomes rigid when deoxygenated and distorts the RBC shape

  2. Abnormal RBC block arteries causing hypoxia, pain, and organ damage

  3. Repeated cycles make RBC fragile with a life of 10-20 days
• Hemolysis is the premature destruction of RBC
• Causes of Hemolysis


  • Inherited diseases (e.g., sickle cell anemia, thalassemia, and G6PD deficiency), infections, drugs, transfusion of mismatching blood, hypersplenism, extreme temperatures, injection of hypotonic solutions
• Jaundice (hyperbilirubinemia) is the yellowish discoloration of the skin, conjunctiva, sclera, and other mucous membranes due to hyperbilirubinemia
• White Blood Cells (Leukocytes)


  Make about 1% of the blood
• White Blood Cells (Leukocytes)


  Main function is to protect the body from infections by phagocytizing bacteria, producing antibodies, playing a role in inflammation, allergic reaction, and anticoagulation
• Production of Leukocytes


  1. Produced in the bone marrow

  2. Stimulated by Interleukins (ILs) and Colony stimulating factors (CSFs)
• Types of Leukocytes


  • Granulocytes (Neutrophils, Eosinophils, Basophils), and agranulocyte (Monocytes, and Lymphocytes)
• Granulocytes are different in size, cytoplasm granular appearance, nucleus shape, and staining characteristics
• Granulocytes - Neutrophils


  Highly mobile phagocyte. Migrate out of blood vessels to fight/engulf bacteria. Contain lysosome enzymes that breakdown bacteria. Have nucleus with 2 – 5 lobes. They make up 54 - 62% of leukocytes
• Granulocytes - Eosinophils


  Kill certain parasites and moderate inflammation and allergic reaction. Have coarse granules in the cytoplasm. They make up 1 - 3% of leukocytes
• Granulocytes - Basophils


  Produce heparin (anticoagulant) and histamine. Have few granules and account for <1% of leukocytes
• Types of White Blood Cells (Leukocytes)

  • Neutrophils
  • Eosinophils
  • Basophils
  • Monocytes
  • Lymphocytes
• Neutrophils


  1. Migrate out of blood vessels to fight/engulf bacteria

  2. Contain lysosome enzymes that breakdown bacteria

  3. Have nucleus with 2 – 5 lobes

  4. Make up 54 - 62% of leukocytes
• Eosinophils


  1. Kill certain parasites and moderate inflammation and allergic reaction

  2. Have coarse granules in the cytoplasm

  3. Make up 1 - 3% of leukocytes
• Basophils


  1. Produce heparin (anticoagulant) and histamine

  2. Have few granules

  3. Account for <1% of leukocytes
• Monocytes


  1. The largest circulating cells with nuclei of various shapes

  2. May leave the blood stream and differentiate to become a wandering macrophage that engulfs foreign particles

  3. Contain lysosomes and phagocytize bacteria and larger particles
• Lymphocytes


  1. The smallest leukocytes and can live for many years

  2. Carry out specific immune functions
• Normal WBC count is between 4,500 and 10,000 cells/ml
• Leukocytosis is when WBC count is >10,000/ml, indicating conditions such as infection, inflammation, stress, or intense exercise
• Leukemia is cancer of the blood or bone marrow with WBC count up to 10x normal