Pathophysiology of Hematologic system Lecture #2 sahar al hogail

1. Pathophysiology of Hematologic systemLecture #2sahar al hogail

2. Hematologic system Hematology is the study of blood and all its components. This is the principal system by which nutrients, elements, and more are carried to tissues and carry away wastes..

3. Components of the Hematologic System The blood and the blood forming sites, including the bone marrow and the reticuloendothelial system. All the blood elements Lymphoid Organs • Plasma • Blood cells e.g. Spleen and the bone marrow.

4. Blood Is a fluid connective tissue. It circulates continually around the body, allowing constant communication between tissues distant from each other.

5. Blood Components • Plasma -55% of total blood volume. Mostly water 91% Soluble blood proteins 7% Hormones Nutrients 2% Electrolytes • Blood elements -45% of total blood volume. Red blood cells White blood cells Blood platelets

6. Composition of Blood

7. Plasma • Liquid part of blood • Pale yellow made up of 91% water,9% other. • Colloid: liquid containing suspended substances that don’t settle out. • Albumin: Important in regulation of water movement between tissue. • Globulin: Immune system or transport molecules. • Fibrinogen: Responsible for formation of blood cell.

8. Blood Cells • Erythrocytes: RBC • Leukocytes: WBC • Neutrophil • Monocyte • Eosinophil • Basophil • Lymphocytes: T lymphocytes, B lymphocytes. • Thrombocyte: Platelet

9. Serum is that part of blood which is similar in composition with plasma but exclude clotting factors Plasma – clotting factors = Serum

10. Functions of the Hematologic System 1) Transport Medium: -Transports gases , nutrients, vitamins , hormones and waste products. -This is achieved by RBCs and plasma 2) Defensive Function: -This function is achieved by white blood cells -Through phagocytosis of the invading microorganisms or formation of antibodies and sensitized T lymphocytes against those invading pathogens.

11. Functions of the Hematologic System 3) Hemostatic Function: -Hemostasis means stoppage of extravasation of blood caused by injury of a blood vessels. -This function is achieved by the platelets and the coagulation factors present in blood. 4) Homeostatic Function: -Homeostasis means to keep the composition of internal environment constant. -This is achieved by the whole blood

13. Fate of Erythrocytes • Unable to divide, grow, or synthesis protiens. • Wear out in 100 to 120 days. • Removed by phagocytosis in the spleen or liver. • New RBCs are made by stem cells in bone marrow. • Production increases when oxygen level decreases or during pregnancy.

14. Hemoglobin is the protein molecule in red blood cells that carries oxygen from the lungs to the body's tissues and returns carbon dioxide from the tissues back to the lungs. Hemoglobin is made up of four protein molecules (globulin chains) that are connected together.

15. Normal values related to RBCs • Red blood cell count: 4.0 to 5.5 million/mL of blood • Hemoglobin: 14.0 to 17.5 grams/100 mL for males; 12.0 to 16.0 grams/100 mL for females • Hematocrit (% of red blood cells): 42% to 52% for males; 36% to 48% for females

16. Normal values related to WBCs • Total leukocyte count: 4000 - 1 l,000/mm3. * Classification: differential leukocyte count: I. Granular leucocytes : • Neutrophils: 60-70%. • Eosinophils: 2 - 4%. • Basophils: 0 - 1%.

17. II. Agranular leucocytes : • Lymphocytes: 20 - 30%. • Monocytes: 2 - 8%.

18. Normal values related to hemostatic function (platelets and coagulation factors) 1) Platelet count: 1/4 - 1/2 millions/mm3 (average 300,000/mm3). 2) Bleeding Time: normally after 1 - 6 minutes. 3) Tests For Coagulation Function: I-The Whole Blood Coagulation Time: is from 6 - 10 minutes 2- The Activated Partial Thromboplastin Time: is 30- 40 seconds. 3- Prothrombin Time: is from10 - 14 seconds

19. Q What are the functions of Hematologic System?

20. Pathophysiology related to RBCs functions:

21. ANEMIA Definition:decreased red blood cell count or decreased hemoglobin percent General manifestation of anemia: In anemia, there is decreased O2 transport to tissues → 1-Pale or yellowish skin 2-Fatigue 3-Cold hands and feet 4-Headache •Shortness of breath 5-Ischemia 6-Blurring of vision 7- Irregular heartbeat •

22. Types of anemia Based on red cell morphology, anemia is classified into: • Normocytic normochromic anemia:normal size and normal Hg content of each RBC • Microcytic hypochromic anemia:small size and smaller Hg content of each RBC • Macrocytic anemia: increased size of each RBC

23. Normocyticnormochromic anemia Results from: A) Decreased production of RBCs: caused by depression of bone marrow → decreased all blood elements including RBCs (aplastic anemia) Bone marrow is a red, spongy material inside your bones that produces stem cells, which give rise to other cells. Stem cells in the bone marrow produce blood cells — red cells, white cells and platelets. Causes of aplastic anemia 1-Radiation 2-Chemicals 3-Chemotherapy 4-Certain antibiotics 5- infection 6- Toxins B) Very rapid loss of RBCs: due to 1- Massive hemorrhage → hemorrhagic anemia 2-Hemolysis of RBCs → hemolytic anemia

24. Hemolytic anemiaThis group of anemia develops when red blood cells are destroyed faster than bone marrow can replace themeither in the blood vessels or elsewhere in the human body. Hemolysis of RBCs may be: *Acquired: caused by : • chemical toxins, bacterial toxins, • drugs (quinidines, snake venom), • Autoimmune : incompatible blood transfusion • Cancers. • Certain viral infection and Parasitic infection (malaria) *Heriditary:e.g, Hereditary spherocytosis, sickle cell anemia and thalassemia

25. Hereditary sperocytosis: RBCs are abnormally sphere shaped → abnormally fragile → hemolysis Sickle cell anemia is an inherited form of anemia, it's caused by a defective form of hemoglobin, the red blood cells become rigid and sticky and are shaped like sickles or crescent. These irregularly shaped cells can get stuck in small blood vessels, which can slow or block blood flow and oxygen to parts of the body. Thalassemia Inherited blood disorders in which the body is not able to make enough hemoglobin,. This causes the body to make fewer healthy red blood cells than normal. → increased RBCs fragility → hemolysis of RBCs

26. 1- Common manifestations of anemia 2- Hemolysis of RBCs → Jaundice, i.e, yellowish coloration of skin and mucous membranes due to increased blood bilirubin 3-Sickling of RBCs in sickle cell anemia → increased blood viscosity → • Decreased blood flow to tissues → ischemia, hypoxia &pain 4-Splenomegally Manifestations of hemolytic anemia:

27. II) Microcytic hypochromic anemia • RBCs are smaller in size and contain smaller amount of Hg than normal RBCs • Caused by iron deficiency • Causes of iron deficiency: 1-Decreased iron intake: especially occurs in vegetarians , infants and females in reproductive periods 2-Decreased iron absorption from intestine 3-Chronic blood loss e.g, bleeding piles, bleeding peptic ulcers and neoplasia (an abnormal growth of tissue)

28. III) Macrocytic anemia • RBCs are larger in size than normal RBCs always associated with insufficient numbers of cells and often also insufficient hemoglobin content per cell • Caused by vitamin B12 or folic acid deficiency

29. Pathophysiological Effects of Anemia: Decreased blood viscosity in anemia ---> increased rate of blood flow --> increased venous return --> increased cardiac output. -The increase in cardiac output compensates for the decreased 02 content in the anemic blood, and the tissues will not suffer from hypoxia.

30. In hemolytic anemia, there is excessive production of bile pigments causing jaundice. In pernicious anemia (is a condition in which the body can't make enough healthy red blood cells because it doesn't have enough vitamin B12), there are sensory disturbances due to degeneration of dorsal column of spinal cord.

31. Types of anemia ? • Normocytic normochromic anemia: • Microcytic hypochromic anemia: • Macrocytic anemia:

32. Polycythemia • Means the RBC count is greatly increased • Types: I)Relative polycythemia:decreased plasma volume → increased concentration of RBCs

33. II) Primary polycythemia (polycythemia vera): Caused by bone marrow makes too many RBCs may also result in production of too many of the other types of blood cells — white blood cells and platelets. These excess cells thicken your blood and cause complications, such as such as a risk of blood clots or bleeding. III) Secondary polycythemia:caused by chronic hypoxia, e.g, living at high altitudes.

34. Manifestations of polycythemia: 1- Increased blood volume 2- Increased blood viscosity → • Risk of thrombosis • Occlusion of small blood vessels • Impaired blood flow to tissues (ischemia) 3-Hepatosplenomegally due to pooling of blood

35. Treatment of polycythemia • 1-Giving fluids to dilute blood in relative polycythemia • 2-Removal of part of blood to decrease blood volume and blood pressure in secondary polycythemia • 3-Use of chemotherapy to kill the hyperactive bone marrow stem cells in primary polycythemia

36. Pathophysiology of hemostasis Definition of hemostasis: stoppage of bleeding when a blood vessel is injured Steps of hemostasis: 1-Vasoconstriction of blood vessel 2-Formation of platelet plug . 3-Formation of blood clot . 4-Growth of fibrous tissue

37. Abnormalities of hemostasis I ) Increased bleeding tendencies: Causes: Abnormalities in coagulation process Abnormalities in blood platelets 2 ) Increased blood coagulability

38. Abnormalities in coagulation process→ increased bleeding tendencies Causes: -Genetic : e.g, hemophilia -Acquired: Vit K deficiency Liver diseases Drug-induced Characteristics: 1-Increased coagulation time

39. 1-Hemophilia • Is a rare bleeding disorder in which the blood doesn't clot normally, caused by deficiency of some clotting factors. Manifestations: • Mild, moderate to severe bleeding disorders • Excessive bleeding with trauma or surgery • Bleeding into soft tissues (muscles and joints) Treatment of hemophilia: • Avoidance of injury and prevention of bleeding • Replacement of the deficient clotting factors

40. 2-Vitamin K deficiency: • Vit K is required for synthesis of clotting factors II,VII,IX & X • Sources of Vit K: Exogenous: from diet Endogenous: from bacteria flora of intestine • Causes of deficiency: 1-Intestinal malabsorption,. 2-Destruction of bacteria flora by antibiotics • Treatment: 1- Vitamin K administration 2-Supplementation of deficient clotting factors

41. 3-Liver diseases: • Clotting factors are synthesized in the liver. • Liver diseases → decreased production of clotting factors → defect in blood coagulation → increased bleeding tendencies • Examples of liver diseases: hepatitis, cirrhosis, liver cancer, liver failure 4-Drug induced : Use of anticoagulants, e.g, Warfarin and heparin

42. Abnormalties in blood platelets→ increased bleeding tendencies (Purpura) • Include: 1-Decreased platelet count (thrombocytopenic purpura) 2-Impaired platelet functions (thrombocytoasthenic purpura) • Charactrized by: 1-Prolonged bleeding time

43. Increased blood coagulability • Causes: 1-Inherited disorders of coagulation 2- Polycythemia 3-Obesity 4- Prolonged bed rest 5-Cancer 6- Venous stasis 7-Sepsis 8- Trauma or surgery • Danger: Increased risk of venous thrombosis and emboli. Embolus: which may be a blood clot, fat globule, gas bubble or foreign material in the bloodstream. This can cause a blockage in a blood vessel.

45. Thanks