Details of Blood

Composition of Blood

Plasma

• Constitutes: About 55% of blood's volume.
• Components:
  • Water: About 90-92% of plasma.
  • Proteins: 7-8% (e.g., albumin, globulins, fibrinogen).
  • Electrolytes: Sodium, potassium, calcium, bicarbonate, etc.
  • Nutrients: Glucose, amino acids, vitamins.
  • Waste Products: Urea, uric acid.
  • Hormones: Various hormones carried from endocrine glands to target organs.
  • Gases: Oxygen (small amount), carbon dioxide, nitrogen.

Formed Elements

• Red Blood Cells (RBCs) / Erythrocytes:
  • Function: Transport oxygen from the lungs to tissues and carbon dioxide from tissues to the lungs.
  • Characteristics: Biconcave shape, lack nucleus in mature form, contain hemoglobin.
  • Lifespan: Approximately 120 days.
• White Blood Cells (WBCs) / Leukocytes:
  • Function: Defend the body against infection and disease.
  • Types:
    • Granulocytes:
      • Neutrophils: Phagocytize bacteria and fungi.
      • Eosinophils: Combat parasites and are involved in allergic reactions.
      • Basophils: Release histamine during inflammatory responses.
    • Agranulocytes:
      • Lymphocytes: Include B-cells (produce antibodies), T-cells (cell-mediated immunity), and natural killer cells (destroy virus-infected cells).
      • Monocytes: Differentiate into macrophages and dendritic cells, which phagocytize pathogens and present antigens.
• Platelets / Thrombocytes:
  • Function: Involved in blood clotting (hemostasis).
  • Characteristics: Small cell fragments derived from megakaryocytes.
  • Lifespan: About 7-10 days.

Functions of Blood

• Transportation:
  • Oxygen and Carbon Dioxide: Transported between lungs and tissues.
  • Nutrients: Carried from the digestive system to cells.
  • Hormones: Distributed from endocrine glands to target organs.
  • Waste Products: Transported to kidneys, liver, and lungs for excretion.
• Regulation:
  • Temperature: Maintains body temperature through heat distribution.
  • pH Balance: Maintains acid-base balance with buffers.
  • Fluid Balance: Regulates fluid distribution in body tissues.
• Protection:
  • Clotting Mechanism: Prevents blood loss through clot formation.
  • Immune Response: WBCs protect against pathogens and foreign substances.

Blood Types

• ABO Blood Group System:
  • Types: A, B, AB, and O.
  • Antigens: Presence of A and/or B antigens on RBCs.
  • Antibodies: Presence of anti-A and/or anti-B antibodies in plasma.
• Rh Blood Group System:
  • Types: Rh-positive (presence of Rh antigen) and Rh-negative (absence of Rh antigen).

Blood Disorders

• Anemia: Reduced RBC count or hemoglobin level, leading to fatigue and weakness.
• Leukemia: Cancer of WBCs, leading to abnormal proliferation of leukocytes.
• Hemophilia: Genetic disorder affecting blood clotting.
• Thrombocytopenia: Low platelet count, causing bleeding and bruising.
• Sickle Cell Disease: Genetic disorder causing abnormally shaped RBCs, leading to various complications.

Blood Donation and Transfusion

• Blood Donation: Voluntary process where a donor gives blood for transfusion purposes.
• Blood Transfusion: Medical procedure to transfer blood or blood components from a donor to a recipient.
• Compatibility: Ensuring donor blood type matches recipient blood type to prevent adverse reactions.

Laboratory Testing of Blood

• Complete Blood Count (CBC): Measures RBCs, WBCs, hemoglobin, hematocrit, and platelets.
• Blood Chemistry Tests: Evaluate levels of glucose, electrolytes, enzymes, and waste products.
• Coagulation Tests: Assess clotting function (e.g., PT, aPTT).
• Blood Typing: Determines ABO and Rh blood groups.