Understanding Blood Composition and Cell Formation

1. Chapter 12: Blood

2. Blood Volume • Roughly 5 liters per person • Blood is heavier than water (components are made primarily of water with other biochemicals added in!) • Varies with: • Body size • Changes in fluid and electrolytes/salt • Amount of adipose fat tissue • Gender (males have more than females!)

3. Blood Composition

4. Hematocrit • Def: % of formed elements in blood • Mostly red blood cells (RBCs) – 55% • WBCs and platelets– less than 1% • Normal values • In males- mid to high 40’s • In females- low 40’s • When centrifuged/spun: • White blood cells (WBCs) and platelets form a thin very thin layer on top – called “buffy coat” – between plasma and RBCs • Remaining ~45% - plasma

6. Formation of Blood cells • Hematopoiesis • Def: process by which immature stem cells become specialized • Become either RBC, WBC or platelets • Location: Occurs in red bone marrow

7. Red Blood Cells • Also called erythrocytes • Biconcave shape • Increases surface area/volume ratio • Mature cells lack nuclei • 1/3 filled with hemoglobin • Oxygen carrying polypeptide molecule

8. Hemoglobin • Composed of four chains (polypeptides) • Also has iron or “heme” group attached • Called oxyhemoglobinwhen oxygen is bound to it (bright red color) • Called deoxyhemoglobin when oxygen is released (darker color)

9. Red Blood Cell Counts • The higher the # of RBCs = higher oxygen carrying capacity • Change in # affects health – greatly! • Used, in part, to help diagnose and evaluate diseases • Typical range • Males: 4,600,000 – 6,200,000 cells per mm3 • Females: 4,200,000 – 5,400,000 cells per mm3

10. Red Blood Cell Life Cycle • Hematopoiesis (red blood cell formation) • Before Birth: yolk sac, liver, and spleen • After Birth: red marrow • Controlled very precisely by homeostatic mechanisms • Production influenced by: • Vitamin B12 • Folic acid • iron

11. Red Blood Cell Life Cycle (cont) • Circulate for 120 days • Old or damaged RBC’s are destroyed (removed from blood circulation daily) • Phagocytized by macrophages in liver or spleen • Hemoglobin is broken into heme and globin • Heme is broken into iron and biliverdin (greenish pigment) • Biliverdin is converted to bilirubin • Iron is stored in liver or brought to marrow • Biliverdin and bilirubin are secreted in bile

12. Control of Red Blood Cell Production

13. White Blood Cells WBC animation • Also called leukocytes • Production stimulated by interleukins and colony-stimulating factors • Two groups: • 1) Granulocytes - have granular cytoplasm • Neutrophils • Eosinophils • Basophils • 2) Agranulocytes- no cytoplasmic granules • Monocytes • Lymphocytes

15. Neutrophils • Granulocyte • Average 54-62% of leukocytes • Fine cytoplasmic granules that are light purple in neutral stain • Nucleus: 2-5 lobes • Lifespan: about 12 hours • Function: phagocytize bacteria and other particles

16. Eosinophils • Granulocyte • Average 1-3% of leukocytes • Coarse cytoplasmic granules that are deep red in acid stain • Nucleus: 2 lobes • Lifespan: about 12 hours • Function: destroy certain parasites and control inflammation or allergic reactions

17. Basophils • Granulocyte • Average ‹1% of leukocytes • Relatively few, irregularly shaped cytoplasmic granules that are deep blue in basic stain • Nucleus: 2 lobes • Lifespan: about 12 hours • Function: release heparin and histamine

18. Monocytes • Agranulocyte • Average 3-9% of leukocytes • Nucleus: Varied shape • Lifespan: several weeks or months • Function: phagocytize materials

19. Lymphocytes • Agranulocyte • Average 25-33% of leukocytes • Nucleus: Large and round • Lifespan: may live for years • Function: function in immune response

20. White Blood Cell Count WBC animation • Normal range: 5,000-10,000 mm3 • Differential White Blood Cell Count • Distinguish how many of each type • Can be important for diagnosing some disorders/problems • Excessive: • If your WBC count exceeds 10,000, this is leukocytosis(infection) • Ex: Appendicitis • Deficiency: • If you WBC count is below 5,000, this is leukopenia(low count) • Ex:typhoid fever, influenza, measles, mumps, chickenpox, AIDS, polio

21. Thumbs Up, Thumbs Down • White blood cells are also called leukocytes • UP!!!  • When discussing hematocrit, WBCs make up the majority of your blood. • DOWN!!!  • The more WBCs you have, the better you’re probably feeling. • DOWN!  • Lymphocytes function to assist your immune system • UP!!! 

22. WBC REVIEW! • Neutrophils are granulocytes. • YES!!!  • Basophilsphagocytize materials. • NO!!!  • Monocytes make up the majority of your WBCs. • NO!!!  • Have an excessive WBC count can mean an infection like appendicitis. • YES!!! 

23. Blood Platelets • Also celled thrombocytes • Made from megokaryocyte • Large cells in red bone marrow • Production stimulated by thrombopoietin (hormone) • Lack nucleus • ½ the size of RBC • Lifespan: about 10 days • Function: form blood clots, help close breaks in damaged blood vessels • Normal range: 130,000-360,000

25. Blood Plasma • 91-2% water • Remainder is mixture of biochemicals • Proteins, nutrients, hormones, electrolytes • Function: • Transporting nutrients, gases and vitamins • Regulate fluid and electrolyte balance • Maintain proper pH

26. Plasma Proteins • Main component of dissolved substances • Remain in plasma (not metabolized/broken down) • Types: • 1) Albumin (60%) • Help establish colloid osmotic pressure • Transports lipids and steroid hormones • 2) Globulins (36%) • Transport of ions, lipids and fat-soluble vitamins and some antibodies • 3) Fibrinogen (4%) • Function in blood coagulation and clotting

27. Blood Gases and Nutrients • Most important blood gases: • Oxygen • Carbon dioxide • Plasma nutrients: • Materials absorbed from digestive tract • Ex: Amino acids, simple sugars, nucleotides, lipids • Fats (triglycerides) • Phospholipids • Cholesterol • Lipoproteins • When Fats, phospholipids, cholesterol combine with proteins • Large size

28. Other Blood Substances • Nonprotein Nitrogenous Substances • Amino acids • Urea and uric acid • Electrolytes • Various ions (K+, Ca+, Cl-)

30. Hemostasis • Def: the stoppage of bleeding • Important when blood vessels are damaged (following injury) • Vasospasm • Contraction of blood vessel walls in response to small break • Platelet plug • Platelets adhere to damage and to each other to create a plug; may release serotonin to cause vasoconstriction • If previous two are unsuccessful, blood clot may form (through coagulation)

31. Blood Coagulation • Def: formation of blood clot • Damaged tissue releases tissuethromboplastin(hormone) • After series of rxns, prothrombin activator is created • Prothrombin activator (with Calcium) converts prothrombin to thrombin • Thrombin cuts fibrinogen into fibrin fibers that form a meshwork overthe damage

32. Blood Coagulation (cont)

33. Blood Disorders • Hemophilia • Uncontrolled bleeding (hemorrhaging) following injury, frequent nosebleeds, blood in urine • Inherited clotting disorder • Carried on X chromosome (recessive) • Von Willebrand Disease • Tendency to bleed and bruise easily • Inherited clotting disorder • Far less severe than hemophilia

35. Blood Disorders • Leukemia • Symptoms: • Fatigue, frequent colds/fevers, chills, sweats, bruising, bone pain • Diagnosing: • Few RBCs and platelets, TOO many WBCs (notice the prefix “leuk” from leukocytes) • Cause: • Red bone marrow producing too many granulocytes cancer cells are not controlled – spread • Treatment: • Stem cell transplants, chemotherapy drugs

36. Normal smear Leukemia smear

37. Blood Types • Types: A, B, AB, O • Typing is based on antigens found on RBC’s • Two most important groups: • 1) ABO group • 2) Rh group • + and – of each type • Ex: A-, B-, AB-, O-; A+, B+, AB+, O+

38. ABO System • Blood type is codominant (A and B are BOTH equally dominant) • Possible blood type genotypes (genetic code) • A (IAIA or IAi) • B (IBIB or IBi) • AB (IAIB) • O (ii)

39. ABO Incompatibility

40. ABO Incompatibility • Mixing blood types can cause agglutination

41. Rh Blood Group • Possible Rh Blood Types: • + (++ or +-) • - (--)

42. Erythroblastosis fetalis • Condition cause by Rh incompatibility between mother and fetus

43. Blood Typing Review Questions • I have O- blood. What type can I receive? • O- ONLY • I have AB+ blood. What type can I receive? • ANY!!! • I have B- blood. Who can take my blood? • B+ or B-; AB+ or AB-