RBCS & WBC

Page 1: Introduction

  • Human PHYSIOLOGY

  • Dr. Maryam Mosad Elmasry

  • Lecturer of Physiology 1

Page 2: Chapter Overview

  • Topic: BLOOD PHYSIOLOGY

Page 3: Blood Composition

  • Total Blood Volume Composition:

    • Plasma: 55%

    • WBC & Platelets: <1%

    • RBC: 45%

  • Fluid Part - Plasma: 90% Water, 10% solids

    • RBC: 6-8%

    • Plasma Proteins ~7%

    • WBC: ~2%

    • Nutrients, waste products, dissolved gases, hormones: <1%

    • Minerals: Na+, K+, HCO3-

Page 4: Functions of Blood

  • Transport Function:

    • Carries O2 from lungs to tissues; CO2 from tissues to lungs.

    • Transports absorbed substances from GIT to liver and tissues.

    • Carries waste products to kidneys for excretion.

    • Transports hormones to target tissues to regulate cell function.

Page 5: Additional Functions of Blood

  • Hemostatic Function: Clots to seal blood vessel injuries.

  • Defensive Function:

    • Forms antibodies against pathogens.

    • WBCs attack invading organisms.

  • Regulation: Helps maintain body temperature.

Page 6: The Plasma

  • Description: A clear fluid, about 55% of blood volume.

    • Composition:

      • 90% Water

      • 10% Solids (Plasma Proteins, Organic & Inorganic substances)

  • Key Plasma Proteins:

    • Albumin: 4.5 - 5.5 g/dl

    • Globulin: 2.5 – 3 g/dl

    • Fibrinogen: 0.3 – 1 g/dl

    • Prothrombin: 0.01 – 0.05 g/dl

    • Others: Urea, uric acid, creatinine, glucose, amino acids, cholesterol.

Page 7: Functions of Plasma Proteins

  1. Colloid Osmotic Pressure: Maintains fluid exchange between blood and tissues.

  2. Immune Function: Gamma Globulin forms antibodies.

  3. Arterial Blood Pressure: Contributes to viscosity via Fibrinogen, maintaining peripheral resistance.

  4. Clotting: Vital in blood clot formation (Clotting Factors).

  5. Protein Reserve: Acts as an energy source during starvation.

Page 8: Red Blood Cells (RBCs)

  • Definition: Also known as Erythrocytes.

  • Characteristics: Most abundant cells, red color due to hemoglobin.

  • Lifespan: Average 120 days in circulation.

Page 9: RBC Composition

  • Contains 60% Water

  • Chief Cation: K+

  • Anions: Cl-, HCO3-, phosphate, Hb.

Page 10: Normal RBC Count

  • Adults:

    • Females: 4 - 5 million/mm3

    • Males: 5 - 6 million/mm3

Page 11: Hemoglobin (Hb)

  • Definition: Red pigment in RBC, binds O2.

  • Structure: Globin (4 polypeptide chains) + Heme (4 iron groups).

  • Function: Each hemoglobin can pick up to 4 O2 molecules.

  • Normal Hb Level: ~15 g/dL

Page 12: Erythropoiesis (RBC Formation)

  • Process: Pluripotent stem cells differentiate into Proerythroblasts, which become Erythrocytes.

  • Site of Formation:

    • Liver and spleen during early embryonic life.

    • Bone marrow after 6 months of pregnancy.

    • Exclusively in flat bones after age 20.

  • Regulation: Feedback control dependent on RBC levels.

Page 13: Regulation of Erythropoiesis

  • Oxygenation: Main regulator of RBC production, stimulated by Erythropoietin (secreted by kidneys & liver).

  • Stimuli for Erythropoietin:

    • Hypoxia (e.g., anemia, hemorrhage, lung disease, high altitudes).

Page 14: Dietary Substances for Erythropoiesis

  • Essential Nutrients:

    • Proteins: High biological value essential for Hb synthesis.

    • Iron: Important for hemoglobin formation (4-5gms in the body).

    • Vitamins: B12, Folic acid for DNA synthesis.

  • Absorption Factors: Gastric HCI, Vitamin C increase absorption; Phytates, oxalates decrease absorption.

Page 15: Anemia

  • Definition: Decrease in RBC count or Hb concentration (<11g/dL).

  • Causes: Rapid loss or slow production of RBCs.

  • Symptoms: Fatigue, weakness, pale skin, increased heart workload, dizziness, decreased oxygenation.

Page 16: Anemia Classification by Cause

  1. Aplastic Anemia: Bone marrow fails to produce RBCs.

  2. Deficiency Anemia: Iron, Vitamin B12, or Folic acid deficiencies.

  3. Hemorrhagic Anemia: Blood loss due to various factors.

  4. Hemolytic Anemia: Excessive destruction of RBCs.

  5. Renal Anemia: Defective erythropoietin secretion.

Page 17: Anemia: Continued Classification

  • Aplastic Anemia: Failure to produce adequate RBCs.

  • Hemorrhagic Anemia: Excessive blood loss from trauma, ulcers, etc.

  • Hemolytic Anemia: Metabolic defects resulting in RBC rupture.

Page 18: Anemia Based on Cell Size and Hb Content

  1. Microcytic Hypochromic Anemia: Small RBCs, low Hb content (e.g., Iron deficiency).

  2. Macrocytic Hypochromic Anemia: Large RBCs, low Hb content (e.g., B12 or folic acid deficiency).

  3. Normocytic Normochromic Anemia: Normal size and hemoglobin content but lower total counts (e.g., acute hemorrhage).

Page 19: Blood Groups

  • ABO System: Classification based on A and B antigens on RBCs.

  • Antigen Presence:

    • Type A: A antigen, Anti-B antibodies in plasma.

    • Type B: B antigen, Anti-A antibodies in plasma.

    • Type AB: Both antigens, no antibodies.

    • Type O: No antigens, Anti-A and Anti-B antibodies.

Page 20: Blood Type Reactions

  • Type A Blood: No agglutination with type A donor.

  • Type B Blood: Agglutination occurs with respective antigens.

  • Rh factor: 85% Rh positive, 15% Rh negative.

Page 21: Erythroblastosis Fetalis

  • Caused by Rh incompatibility between mother and fetus.

  • Consequences: Hemolytic anemia in fetus; may result in severe conditions like jaundice or death.

  • Prevention: Anti-Rh antibodies for Rh-negative mothers post-delivery.

Page 22: Blood Transfusion

  • Indications:

    1. Severe trauma or surgical hemorrhage.

    2. Severe anemia.

    3. Erythroblastosis fetalis.

Page 23: Blood Transfusion Compatibility

  • Blood Typing: Donor and recipient blood must be compatible (ABO and Rh).

  • Cross-Matching: Testing for compatibility before transfusion.

  • Precautions: Ensure healthy donors, blood storage at 4° C, and within 5 weeks of collection.

Page 24: Dangers of Blood Transfusion

  • Risks include hemolytic reactions, mechanical overload, and hyperkalemia.

  • Potential transmission of diseases (e.g., AIDS, hepatitis).

  • Bacterial contamination can lead to shock.

Page 25: White Blood Cells (WBCs)

  • Definition: Mobile units of the body's immune system.

  • Count: 4000-11000/mm3

  • General Functions:

    1. Engulf pathogens.

    2. Initiate immune response.

    3. Remove dead or injured cells.

    4. Destroy cancer cells.

Page 26: White Blood Cell Types

  • Granulocytes: Neutrophils, Eosinophils, Basophils.

  • Agranulocytes: Monocytes, Lymphocytes.

  • Formation: All made in the bone marrow except lymphocytes (in lymphoid tissues).

Page 27: Conclusion

  • Thank you!