Heamatology

1. Components of Blood

Blood has four main components:

  • Red Blood Cells (RBCs): Also known as erythrocytes, they carry oxygen from the lungs to tissues and remove carbon dioxide.
  • White Blood Cells (WBCs): Also called leukocytes, they are part of the immune system and help fight infection.
  • Platelets (Thrombocytes): Involved in blood clotting.
  • Plasma: The liquid part of blood that carries cells, nutrients, hormones, and waste products.

2. Hematopoiesis

This is the process of blood cell formation, which occurs primarily in the bone marrow. There are three main lines:

  • Erythropoiesis – Formation of RBCs
  • Leukopoiesis – Formation of WBCs
  • Thrombopoiesis – Formation of platelets

3. Hemoglobin and Oxygen Transport

  • Hemoglobin is a protein in RBCs that binds oxygen.
  • Each hemoglobin molecule can carry four oxygen molecules.
  • Iron is a vital component of hemoglobin.

4. Blood Groups

  • Determined by antigens on the surface of RBCs.
  • Major systems: ABO and Rh.
  • Blood typing is essential for transfusions to prevent hemolytic reactions.

5. Coagulation and Hemostasis

  • Hemostasis is the process that prevents excessive bleeding when a blood vessel is injured.
  • It involves:
    1. Vasoconstriction
    2. Platelet plug formation
    3. Coagulation cascade (involving clotting factors)
  • Disorders: Hemophilia, Von Willebrand disease, etc.

6. Common Hematological Diseases

  • Anemia: Deficiency in RBCs or hemoglobin.
  • Leukemia: Cancer of white blood cells.
  • Lymphoma: Cancer of lymphatic tissue.
  • Thalassemia: Genetic disorder affecting hemoglobin.
  • Sickle Cell Disease: Abnormal hemoglobin causing RBCs to sickle.

7. Diagnostic Tests in Hematology

  • Complete Blood Count (CBC): Measures RBCs, WBCs, platelets, hemoglobin, and hematocrit.
  • Peripheral Blood Smear: Microscopic examination of blood cells.
  • Bone Marrow Aspiration and Biopsy: Used to diagnose blood disorders and cancers.
  • Coagulation Tests: PT, aPTT, INR for clotting disorders.

8. Hematology in Clinical Practice

  • Used in:
    • Diagnosing infections, anemia, clotting issues
    • Monitoring chemotherapy
    • Managing chronic diseases (e.g., kidney failure, which affects erythropoietin production)