MS Hematology (midterm)

• What are the seven major functions of blood?

  • Transport of gases, nutrients, waste products
  • Transport of processed molecules
  • Transport of regulatory molecules
  • Regulation of pH and osmosis
  • Maintenance of body temperature
  • Protection against foreign substances
  • Blood clotting for tissue repair
• What is the temperature of blood?


  38 degrees Celsius
• What is the average total blood volume in adults?


  Approximately 5 liters
• What are the components of blood?

  • Liquid plasma
  • Formed elements (erythrocytes, leukocytes, platelets)
• What percentage of blood volume do erythrocytes account for?


  About 95% of formed elements
• What is hematocrit?


  The percentage of RBCs out of the total blood volume
• What is the pH range of blood?


  1. 35 - 7.45
• What is the average blood volume for males and females?


  Males: 5-6 L; Females: 4-5 L
• What is the primary component of plasma?


  Water (91%)
• What are the main proteins found in plasma?

  • Albumin (58%)
  • Globulins (38%)
  • Fibrinogen (4%)
• What is the function of albumin in plasma?


  Helps maintain osmotic pressure
• What role do globulins play in the blood?


  • Immunity: antibodies and complement
  • Transport: bind to molecules such as hormones
  • Clotting factors
• What is the function of fibrinogen in plasma?


  Converted to fibrin during clot formation
• What are the formed elements of blood?

  Erythrocytes, leukocytes, and platelets
• What is the lifespan of red blood cells (RBCs)?

  100-120 days
• What is hematopoiesis?

  Blood cell production
• Where does hematopoiesis occur after birth?

  In the red bone marrow of the axial skeleton and girdles
• What is the role of hemocytoblasts?

  They give rise to all formed elements of blood
• What is the structure of red blood cells (RBCs)?

  Biconcave discs, anucleate, with essentially no organelles
• What is the primary function of red blood cells?

  Dedicated to respiratory gas transport
• What is hemoglobin (Hb) and its function?

  It is a protein that functions in gas transport
• How does the structure of RBCs contribute to their function?

  The biconcave shape provides a large surface area for gas exchange
• What determines the color of blood?

  Oxygen content: oxygenated blood is bright red, deoxygenated is darker red
• How is oxygen transported in the blood?


  98.5% bound to hemoglobin, ~1.5% dissolved in plasma
• What is the role of carbonic anhydrase in RBCs?


  It catalyzes the conversion of carbon dioxide and water to carbonic acid
• What is erythropoiesis?


  The production of red blood cells (RBCs)
• What triggers the release of erythropoietin (EPO)?


  Hypoxia due to decreased RBCs, decreased oxygen availability, or increased tissue demand for oxygen
• What happens to old RBCs?


  They become rigid and fragile, and are engulfed by macrophages
• What is the function of macrophages in relation to RBCs?


  They engulf dying RBCs and separate heme and globin
• What is the function of platelets?


  They function in clotting by forming platelet plugs and clots
• What are the three phases of blood loss prevention?

  1. Vascular spasms
  2. Platelet plug formation
  3. Coagulation
• What is coagulation?


  The formation of a clot, a network of protein fibers called fibrin
• What initiates the extrinsic pathway of coagulation?


  The release of thromboplastin from damaged tissue
• What is the role of activated Factor X in coagulation?


  It converts prothrombin to thrombin
• What are the types of white blood cells (WBCs) and their functions?


  • Granulocytes: neutrophils, eosinophils, basophils
  • Protect against microorganisms and remove dead cells
  • Agranulocytes: lymphocytes, monocytes
  • Lymphocytes: B cells (produce antibodies) and T cells (attack infected cells)
  • Monocytes: differentiate into macrophages
• What are the characteristics of granulocytes?


  • Contain large cytoplasmic granules
  • Have lobed nuclei
  • Are all phagocytic cells
• What are the characteristics of agranulocytes?


  • Lack visible cytoplasmic granules
  • Have spherical (lymphocytes) or kidney-shaped (monocytes) nuclei
• What is the role of eosinophils?


  • Account for 1-4% of WBCs
  • Reduce inflammation and counteract allergies
  • Lead the body's defense against parasitic worms
• What is the role of basophils?


  • Account for 0.5% of WBCs
  • Contain histamine (vasodilator) and heparin (prevents clot formation)
• What is the function of lymphocytes?


  • Account for 25% or more of WBCs
  • B cells produce antibodies
  • T cells protect against viruses and infected cells