Introduction to Blood and Immunity

Introduction to Blood

• Blood is a circulatory fluid that carries oxygen and nutrients to tissues while removing waste products.
• Blood is made up of plasma (55%) and formed elements (45%).
  • Plasma: Water, proteins (albumin, globulins, fibrinogen), hormones
  • Formed elements: Red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes)

Blood Cells

• Erythrocytes (Red Blood Cells): Responsible for carrying oxygen and carbon dioxide
• Leukocytes (White Blood Cells): Combat infections and provide immunity
• Thrombocytes (Platelets): Important for clotting (hemostasis)

Immunity

• Immunity is the body's defense mechanism against harmful microorganisms and foreign substances.
• Two main types of immunity:
  • Innate immunity: Non-specific, inborn defenses such as the skin barrier and mucous membranes.
  • Adaptive immunity: Acquired defense that is specific to certain pathogens.

Components of Adaptive Immunity

• T cells: Provide cell-mediated immunity, directly attacking foreign invaders
• B cells: Responsible for humoral immunity, producing antibodies

Medical Terminology Related to Blood

• Hem/o, Hemat/o: Blood (e.g., hemopathy)
• Erythr/o: Red (e.g., erythropoiesis)
• Thromb/o: Clot (e.g., thrombosis)
• Leuk/o: White (e.g., leukocytosis)
• Hematocrit: The proportion of red blood cells in the blood
• Hemostasis: The process of stopping bleeding, including blood clot formation

Medical Terminology Related to Immunity

• Immun/o: Refers to immunity or the immune system.
• Immunization: The process of inducing immunity.
• Immunoglobulin (Ig): Antibody proteins that protect against infections.
• Antigen: A substance that triggers an immune response.
• Antibody (Immunoglobulin): A protein produced by B cells that helps neutralize pathogens.

Disorders Related to Blood

• Anemia: A deficiency of red blood cells or hemoglobin.
• Leukemia: Cancer involving the overproduction of white blood cells.

Disorders Related to Immunity

• Autoimmune diseases: The immune system attacks the body's own cells
• Immunodeficiency Disorders: A weakened immune system, as seen in HIV.

Clinical Case: Iron Deficiency Anemia

• Patient Name: Jane Smith
• Age: 45 years
• Gender: Female
• Occupation: Office Worker
• Presenting Complaint:
  • 2-month history of fatigue, shortness of breath on exertion, and frequent headaches
  • Increased dizziness, especially when standing up quickly
  • Feeling unusually tired despite sleeping well
• Investigations:
  • Complete Blood Count (CBC):
    • Hemoglobin: 9.0 g/dL (normal: 12-15 g/dL)
    • Hematocrit: 28% (normal: 36-46%)
    • Ferritin: 8 ng/mL (normal: 20-200 ng/mL)
    • Iron levels: Low
• Diagnosis: Iron deficiency anemia secondary to chronic blood loss from menorrhagia (heavy menstrual bleeding)
• Treatment: Ferrous sulfate 325 mg PO daily for 3 months.

Additional Medical Terminology

• Neutropenia: A decrease in neutrophils (a type of white blood cell), increasing infection susceptibility.
• Eosinophil: A type of white blood cell involved in allergic reactions and fighting parasitic infections.
• Lymphocyte: A type of white blood cell involved in immune response.
• -phylaxis: Refers to protection or prevention.
  • Prophylaxis: Treatment or action to prevent disease.
  • Anaphylaxis: A severe, potentially life-threatening allergic reaction.
• Lymph/o: Refers to lymph or lymphatic system.
  • Lymphocyte: A type of WBC involved in immune response.
  • Lymphadenopathy: Disease affecting the lymph nodes
• -globulin: Refers to proteins involved in immune response
  • Immunoglobulin: Antibodies critical to the immune response.
  • Gamma globulin: A substance containing antibodies for passive immunity.
• Auto-: Prefix meaning "self."
  • Autoimmune: Immune system attacking the body's own tissues.
  • Autoantibodies: Antibodies attacking the body's own cells.
• -cytosis: Refers to an abnormal increase in the number of cells.
  • Leukocytosis: An abnormal increase in WBCs.
• Hypersensitivity: An exaggerated immune response to a foreign substance.
  • Hypersensitivity reaction: Immune responses causing tissue damage (e.g., anaphylaxis).