Blood

33. Describe the process of leukopoiesis from pluripotent stem cell to monocyte and mature granulocyte.

*pluripotent stem cells* in bone marrow--> *lymphoid stem cells* or *myeloid stem cells* *myeloid stem cell* --> *myeloblast* - promyelocyte begins accumulating generic granules in cytoplasm --> (eosinophilic, basophilic, or neutrophilic) *myelocytes* - mitosis stops, and granules differentiate --> *band cell* - nucleus indents and becomes archered, add a few more antigens, released from bone marrow to the blood when (almost) mature --> *mature granulocyte* (eos. baso. neutro.) stored in bone marrow *myeloid stem cell* --> *monoblast* leaves bone marrow and matures in the intestinal fluid of tissues --> *promonocyte* --> *monocyte*

36. Identify and describe the three phases of hemostasis.

*vascular spasm* - damage to the vessel triggers strong contractions (proportional to the extent of the damage) in vascular smooth muscle --> local vasoconstriction *platelet plug formation* - platelets begin to adhere to endothelium and exposed collagen fibers -platelet adhesion --> platelet activation and release rxn, platelet aggregation -released chemicals: ADP (stimulates platelet aggregation), TXA2 and serotonin (enhance vascular spasms), clotting factors (Ca2+), platelet-derived growth factor (PDGF, promotes repair of blood vessel) -positive feedback cycle (platelets release more chemicals, aggregate more platelets)--> quick formation of platelet plug -prostacyclin (PGI2) and other factors limit platelet aggregation and platelet plug formation specifically to the injury site *coagulation*- clotting mechanism involves cascade of reactions involving various clotting factors or procoagulants 1. formation of prothrombinase via extrinsic pathway and intrinsic pathway

22. What are three common causes of anemia?

1. insufficient number of RBC's -hemorrhagic anemia - loss of blood -hemolytic anemia - RBCs removed more quickly than replaced -aplastic anemia - red bone marrow is inhibited by radiation, drugs, bacterial toxins 2. decreased hemoglobin (Hb) content of RBCs -nutritional deficits of iron and vit. B12, resulting in large and pale RBCs 3. abnormal Hb -thalassemia - absent/incorrect globin chain --> more fragile RBC -sickle-cell anemia - low oxygen in capillary beds, spiky cells cause pain

43. What factors work to localize and control blood clotting?

1. swift removal of clotting factors by normally flowing blood 2. inhibition of activated clotting factors -all of thrombin is bound onto fibrin threads to speed up production of prothrombin activator, activates platelets - KEEPS THROMBIN LOCAL -antithrombin III inactivates any thrombin not bound to fibrin -*heparin* - natural anticoagulant that enhances activity of antithrombin III

12. Describe the molecular structure of hemoglobin (Hb). How does adult Hb (HbA) differ from fetal Hb (HbF)?

2 alpha and 2 beta chains - each chain has a globular shape and a heme group embedded in the center - each heme group contains an atom of iron (Fe2+) - one oxygen atom can reversibly bind to each iron atom fetal Hb has a different globin chain which gives it a higher affinity for oxygen

5. Describe the composition of whole blood.

55% plasma <1% buffy coat 45% erthyrocytes

14. What is the typical lifespan of RBCs?

80-120 days

6. Describe the composition of plasma.

92% water 7-8% plasma proteins - albumins, globulins, fibrinogen and other clotting proteins the 0-1% hormones, etc.

45. What agglutinogens are present on the RBCs of each of the 4 ABO blood types?

A B AB - both O - none

46. What genotypes could account for each of the phenotypes described above (#45).

A - A and O B - B and O AB - A and B O - O and O

48. On the basis of ABO blood groups only, identify which donor blood types are compatible with recipient of each of the 4 ABO blood groups.

A - A, O B - B, O AB - A, B, AB, O O - O

47. What agglutinins are present in the blood plasma of each of the 4 ABO blood types?

A - anti-B B - anti-A AB - none O - anti-A, anti-B

37. Identify the main chemicals released by activated platelets. What role does each factor play in promoting hemostasis?

ADP - stimulates platelet aggregation TXA2 and serotonin - enhances vascular spasms clotting factors - including Ca2+ platelet-derived growth factor (PDGF) - promotes repair of the blood vessel

21. At which stage of development do RBCs leave the bone marrow and enter the circulation?

after they become reticulocytes that are filled to the brim with hemoglobin

25. Which category of leukocyte has the longest life span?

agranulocyte

8. Identify the main types of plasma proteins and describe the general functions of each.

albumins 50-60% - most abundant, main contributor to osmotic pressure of blood, maintain normal pH, transport proteins for lipids (steroid hormones) globulins 33% - transport proteins (produced by liver, bind to solutes around blood), immunoglobulins (antibodies) fibrinogen 4% - clotting protein produced by liver, forms fibrin threads of blood clot

30. Which type of WBC releases heparin and histamine?

basophil

42. What is fibrinolysis? What proteolytic enzyme is involved in fibrinolysis?

breakdown/dissolving the clot involves plasmin - fibrin-digesting enzyme

23. Describe how leukocytes (WBCs) use diapedesis, amoeboid motion, and positive chemotaxis to move around in the body

diapedesis - emigration from the blood vessel to the interstitial fluid, involving movement of WBCs across a blood vessel wall positive chemotaxis - leukocytes follow chemical trail of molecules released by damaged cells or other leukocytes towards pathogen, infection, or injury amoeboid motion - "swimming" through body fluids with flowing cytoplasmic extensions

9. What is the most numerous type of blood cell?

erythrocytes

18. Describe the negative feedback regulation of erythropoiesis.

erythropoietin (EPO) hormone secreted by kidney stimulates RBC production *hypoxia* --> increased rate of EPO secretion - when kidney cells are oxygen deficient, *hypoxia inducible factor (HIF)* accumulates and accelerates synthesis of erythropoietin

17. Name the hormone that stimulates RBC production. What organ releases this hormone?

erythropoietin (EPO), released by kidneys

13. Your textbook states that fetal Hb has a higher affinity for oxygen than does adult Hb. Why is the higher oxygen affinity HbF of benefit to the fetus?

fetus needs to get more oxygen from the mother's blood, which has a bunch of different solutes

3. Blood is classified as what type of tissue?

fluid specialized connective tissue in which living blood cells (formed elements) are suspended in a nonliving fluid matrix (plasma)

24. Identify the two general categories of WBCs and name the specific cells assigned to each category.

granulocytes (lobed nuclei, granules, 12 hr lifespan)- neutrophils, eosinophils, basophils agranulocytes (spherical, oval, or kidney-shaped, longer life span)- monocytes and lymphocytes

16. Describe the Hb breakdown products and tell how they are handled.

heme is separated from the globin *globin* breakdown - amino acids join the amino acid pool of the body *heme* breakdown --> *iron* and *biliverdin* (green pigment) - *iron* binds with *transferrin* for safe transport in the blood or *ferritin* for safe storage in the liver - *biliverdin* is reduced to *bilirubin* (orange pigment) and released to the circulation --> liver --> secreted into the bile --- in the large intestine, *bilirubin* becomes *urobilinogen* (a little to kidneys, releases pale yellow urobilin) (most to large intestines excreted in feces as brown pigment)

34. Identify the 2 specific families of cytokines that regulate leukopoiesis.

interleukins (ILs) - cell-to-cell signaling between WBCs, IL#'s help regulate the rate of leukopoiesis colony-stimulating factors (CSFs) - stimulates specific type of leukocyte

38. Differentiate between the extrinsic and intrinsic pathways of blood clotting (initiation of coagulation)

intrinsic pathway - factors needed are found within the blood -triggered by negatively charged surfaces such as activated platelets, collagen, and glass -slower than extrinsic bc of many intermediate steps extrinsic pathway - tissue factor needed is found outside of the blood -triggered by factor under the damaged endothelium called tissue factor/factor III (TF) -faster than intrinsic, can form a clot in 15 sec

11. Describe the structure and function of mature erythrocytes (RBCs).

mature erythrocytes (RBCs) carry hemoglobin to all cells of the body - flexible, biconcave disk shape - dramatically increases surface area --> much quicker oxygen diffusion into RBC - distortable cytoplasm - able to make 2 complete circuits through small capillary beds every minute

31. Which type of WBC is the largest of all blood cells?

monocyte

32. Which type of WBC matures in the body tissues to become a macrophage?

monocyte

28. Which type of WBC accounts for more than half of all circulating leukocytes?

neutrophils

26. Describe the histological characteristics and general function of each type of WBC.

neutrophils - twice as large as erythrocytes, lilac, 3-6 lobes -phagocytes esp. to bacteria and fungi, killing promoted by respiratory burst (bleach and hydrogen peroxide, peptide "spears") eosinophils - twice as large as erythrocytes, 2-lobed, red -release enzymes to digest parasitic worms that burrow into mucosae basophils - purplish-black, U or S shaped nucleus -release histamine and other mediators of inflammation monocytes - largest leukocytes, pale-blue cytoplasm, purple U or kidney shaped nucleus -phagocytosis, develop into macrophages in the tissues lymphocytes - spherical, large nucleus that occupies most of cell volume -T cells - directly attack virus-infected cells and tumor cells -B cells - give rise to plasma cells, which produce antibodies that are released to the blood

27. List the various types of WBCs in order from most to least numerous.

neutrophils 50-70% lymphocytes 25% monocytes 3-8% eosinophils 2-4% basophils 0.5-1% (never let monkeys eat bananas)

29. Which types of WBCs are important phagocytes?

neutrophils, monocytes

20. At which stage of development does the RBC eject its nucleus?

normoblast prepares to eject the nucleus when nucleus is ejected, becomes reticulocyte

49. When do anti-Rh antibodies form?

on subsequent exposure to Rh positive blood

2. What are typical values for blood pH, specific gravity, volume, and hematocrit?

pH - 7.35-7.45 specific gravity - 1.015-1.024 volume - 5-5.5 L in a 70 kg man, 4-5 L in a woman hematocrit - 47+-5% in males, 42+-5% in females

40. Describe the steps of the common pathway of the coagulation process.

phase 2: prothrombinase (prothrombin activator) converts prothrombin to thrombin phase 3: thrombin converts fibrinogen (soluble) to fibrin (insoluble) strands -fibrin strands glue platelets together --> web that forms the structural basis of clot -thrombin activates factor XIII (fibrin stabilizing factor) - cross-linking enzyme that binds fibrin strands tightly --> fibrin mesh

4. What part of the blood is the non-living matrix?

plasma

19. Describe the stages of RBC development from pluripotent stem cell to mature RBC.

pluripotent stem cell --> myeloid stem cell --> proerythroblast --> erythroblast --> normoblast --> reticulocyte --> mature RBC

35. Describe the development of platelets. What hormone regulates the process of platelet formation?

pluripotent stem cell --> myeloid stem cell --> progenitor cell --> promegakaryoblast (3 nuclei)--> megakaryoblast (5 nuclei)--> megakaryocyte --> platelets -development is essentially multiple mitoses of megakaryoblast w/o cytokinesis -megakaryocyte presses against sinusoid (capillary in red marrow) and sends cytoplasmic extensions through sinusoid wall into the bloodstream -extensions rupture and release platelet fragments into bloodstream thrombopoietin (TPO) hormone regulates process of platelet formation

39. What enzyme is formed by both the intrinsic and extrinsic pathways to initiate the common pathway of blood clotting?

prothrombin activator

10. In adults, where are the formed elements of the blood produced?

red bone marrow of membranous bones (verebrae, sternum, ribs, ilia) and in proximal epiphyses of humerus and femur

15. Where are worn-out/damaged RBCs removed from the blood and broken down? What type of cell performs this function?

removed from the circulation by macrophages in the liver and spleen

41. What is clot retraction?

stabilizes the clot and squeezes out serum (platelets contract - actin and myosin - and pull fibrin strands of the wall together, no serum-dries blood clot) plasminogen --> plasmin - rxn catalyzed by tissue plasminogen activator (tPA) from damaged epithelial cells, urokinase (uPA) -thrombin can indirectly cause plasmin to be activated

1. What are the functions of blood?

transport - oxygen from lungs and nutrients from the digestive tract, metabolic waste products to elimination in the lungs and the kidneys, hormones from endocrine organs regulation - temperature by absorbing and distributing heat throughout the body and to the skin surface , pH as buffers to prevent excessive/abrupt changes, adequate fluid volume protection - preventing blood loss (platelets and plasma proteins) and infection (antibodies, complement proteins, white blood cells)

44. The ABO blood groups are distinguished by the presence or absence of what 2 agglutinogens?

type A and type B

7. What is the primary component of plasma?

water