(Exam 1) 6. Blood and Bone Marrow

*Written Objectives:* 4. Describe the basis of the A, B, O, and Rh blood groupings and their role in health and disease.

*Blood Grouping (typing):* - Surface of RBCs contain genetically determined proteins (antigens, agglutinogens, or isoantigens). --- Responsible for the ABO and Rh blood grouping systems. - Red blood cells have surface bound glycoproteins. --- The carbohydrate portion of the glycoprotein is distinct and provides the basis for ABO blood grouping system. *ABO:* - Based on two agglutinogens, A and B - A, B, AB, and O blood types are not evenly distributed throughout the population - An individual has antibodies against all RBC surface antigens he/she does not possess (*hemolysis of RBCs if patient is given incompatible blood type) *Type A:* - Type A = patients whose RBCs contain only agglutinogen A - Type A = anti-B - Receives blood from types A, O - Donates blood to types A, AB *Type B:* - Type B = patients whose RBCs contain only agglutinogen B - Type B = anti-A - Receives blood from types B, O - Donates blood to types B, AB *Type AB:* (*universal recipient) - Type AB = patients whose RBCs contain only agglutinogen A and B - Type AB - Receives blood from types A, B, AB, and O - Donates blood to type AB *Type O:* (*universal donor) - Type O = patients whose RBCs contain neither Agglutinogen A or B - Type O = anti-A, anti-B - Receives blood from type O - Donates blood to types A, B, AB, O *Rh System:* - Another glycoprotein system associated with RBCs is the Rh system. - Individuals are classified as Rh positive (Rh+) or Rh negative (Rh-). - Rh+ = surface of RBCs have Rh protein (factor) - Rh- = surface of RBCs do not have Rh protein (factor) *Rh incompatibility:* - An Rh- patient infused with Rh+ blood, will develop anti-Rh antibodies. A second infusion with Rh+ blood will cause a severe agglutination reaction. - Rh incompatibility induces a hemolytic transfusion reaction in a recipient and in a newborn. --- In the case of the newborn, an Rh+ fetus is born to an Rh- mother. ------ Some fetal RBCs cross the placenta and enter the maternal blood during delivery, causing the formation of antibodies. ------ To counter this, the mother is injected with RhoGam (antibody to anti-Rh+ antibody) which destroys currently circulating anti-Rh+ antibodies and provides protection against incompatibility reactions in future pregnancies.

*Platelet Clinical Conditions:* (2)

*Thrombocythemia-* - high number of platelets (e.g. proliferative disorders of bone marrow, inflammation, decreased spleen function or splenectomy). *Thrombocytopenia-* - low number of platelets (e.g. hereditary syndromes, leukemia, infections, vitamin B12 deficiency, autoimmune diseases, genetic disorders, DIC).

*WBC Clinical Tests* (4)

*White Blood Cell (WBC) Count-* - Number of all WBCs in a sample. - Normal human WBC count = 5,000-9,000 WBCs/mm3 *Differential White Blood Cell Count-* - Individual numbers of neutrophils (mature and immature), basophils, eosinophils, monocytes, and lymphocytes in a blood sample. *Leukocytosis(human)-* - Greater than 10,000 WBCs/mm3 (e.g. illness, infection, burns, fractures, other injuries, post- exercise, pregnancy, and labor) *Leukopenia (human)-* - Less than 5,000 WBCs/mm3 (e.g. radiation and chemotherapy treatments, anemia, autoimmune diseases, bone marrow diseases, anti-epileptic and anti-psychotic drugs, HIV, AIDs).

*Blood Components:* *Plasma-*

- *Fluid portion:* • 90% water, 10% dissolved substances - *Solids:* • Inorganic ions Na, K, Cl, HCO3, Ca, etc. = 1% • Protein = 8% - *Function:* • Transports nutrients, waste products, hormones • Circulates immunoglubulins and cells of immune system • Contains components of the clotting mechanism.

*Coagulation:* *Prevention-* (3)

- 1. Endothelial cells produce heparin-like surface molecules that inactivate thrombin (*catalyzes the conversion of fibrinogen into fibrin) and some coagulation. - 2. Endothelial cells have surface thrombomodulin molecules that bind with circulating thrombin molecules to form the Protein C complex (*inactivates coagulation factors V, VIII) - 3. Tissue plasminogen activator (t-PA) synthesized by endothelial cells, breaks down fibrin and prevents platelet adhesion.

*Coagulation:* *Normal-* (7)

- 1. Rupture of blood vessels causes immediate vasoconstriction. - 2. Exposed collagen fibers from damaged tissue attract platelets. Initial platelet binding to collagen is weak; von Willebrand's factor (*produced by endothelial cells) enhances platelet binding. - 3. Platelets that initially bind to collagen release compounds stored in their granules (ADP, ATP, ionic calcium, histamine, serotonin, epinephrine, fibrinogen, fibronectin, clotting factors V and VIII, growth factors, platelet factor 4, thromboxane A2). *Has the overall effect of slowing blood flow through vasoconstriction, and stimulating platelet adhesion. Results in the formation of a phospholipid complex (clotting cascade) on the surface of platelets that causes shape changes in platelets and release of substances from secretory granules - stimulates intrinsic coagulation pathway. - *Ca2+ required for coagulation • Binds negatively charged clotting factors of the coagulation cascade to the negatively charged phospholipid surface of platelets. - Vitamin B12 required for coagulation • Acts as a cofactor for a carboxylase produced in the liver. The carboxylase stimulates certain proteins to create Ca2+ binding sites. - 4. Additional aggregation of platelets, with the continuation of the intrinsic coagulation pathway. Fibrinogen and other compounds from platelet granules activates more platelets and enhances platelet binding. Platelets develop pseudopodia that extend into the injury site and between adjacent platelets. More platelets are added to the aggregate and a primary hemostatic plug (*water soluble) is formed. - 5. Damaged tissue releases tissue factor which activates the extrinsic coagulation pathway. Thrombin mediates the conversion of fibrinogen to fibrin (*insoluble). Activation of clotting factor X is the step in the clotting cascade that links the intrinsic and extrinsic pathways, and results in the formation of the secondary hemostatic plug. - 6. Clot retraction occurs as a result of complete fibrin polymerization. Actin and myosin are organized into contractile microfilaments that retract the clot, making it permanent. - 7. Tissue plasminogen activator secreted by endothelial cells converts plasminogen to plasmin (a protease), which breaks up the polymerized fibrin, once the tissue has been repaired.

*Coagulation Disorders:* *Mechanism of DIC-*

- 1. Thrombocytopenia (platelet supply is exhausted) - 2. Depletion of clotting factors (e.g. V, VIII, X, and fibrinogen) - 3. Activation of the fibrinolysis system (break down of fibrin by plasmin) - 4. Increased fibrin degradation products (have anti-coagulation properties because they compete for fibrinogen binding sites on the surface of platelets)

*Platelets:* *Platelet (thrombocyte)-*

- A round or oval biconcave disc, 1.5-3.5 microns in diameter. - 1,500 - 436,00/liter - Purple staining, granular appearance. - Granules contain membrane adhesion molecules, coaglution factors, lysosomal enzymes, peroxidase activity. - Formed from cytoplasmic fragments from megakaryocytes. - Function in blood clotting (*most important), vascular repair, vasoconstriction, opsonization (combine with bacteria).

*Coagulation Disorders:* *Treatment of DIC-*

- Administration of heparin (inhibits clotting; prevents patient from using up all clotting factors and platelets). - Administration of normal plasma or whole blood.

*Blood Proteins:* *Globulins-*

- Alpha globulins (proteases, antiproteases, transport proteins) - Beta globulins (transferrin, other transport proteins) - Gamma globulins (mostly immunoglobulins)

*Red Blood Cells:* • Blood Grouping *Erythroblastosis fetalis-*

- An Rh+ baby is born to an Rh- mother. There is some mixing of fetal and maternal blood during delivery. This causes mother to develop anti-Rh antibodies. - A second pregnancy involving another Rh+ baby will result in maternal anti-Rh antibodies crossing the placenta and attacking the fetal RBCs - *Erythroblastosis can be prevented if mother is injected with anti-Rh gamma2-globulin immediately after delivery or abortion.

*Red Blood Cells:* *Erythrocyte-*

- Biconcave, enucleated (*nucleated in certain species, e.g. birds, fish, reptiles), round disc in most species. --- Biconcave shape places hemoglobin molecules closer to the RBC plasma membrane, which facilitates gas exchange. - Varies in diameter from 3.5-7.5 microns (species dependent) - Stains red to pink in routine histological sections - Contains hemoglobin for transporting oxygen and carbon dioxide --- Hemoglobin (Hb) ------ 68 kDa protein ------ Binds to CO2 and O2 ------ High concentrations of Hb in RBCs ------ 96% of HB in adults is HbA ------ 8% of HbA is subtype HbA1c; HbA1c binds irreversibly to glucose and is used to monitor blood glucose levels (A1c test); Diabetics have increased A1c levels (*any A1c level above 6.0 requires medication) - 120 day average life span - Dead or worn out cells are removed by the spleen and liver.

*Clinical Conditions:* *Anemia-*

- Decrease in the amount of Hemoglobin (Hb) in the blood (Low = <15.g/dl for males and <12 g/dl for females) --- External and internal hemorrhage --- Poor nutrition --- Iron and vitamin B12 deficiencies --- Chronic diseases --- Pregnancy - Anisocytosis --- Alterations in the normal size of RBCs

*Coagulation Disorders:* *Acquired-*

- Depression of clotting factors = may result from liver disease, vitamin K deficiency, coumarin toxicity, and DIC.

*Written Objectives:* 3. Describe the process of hemopoiesis as presented in class.

- Development of peripheral blood cells from a common bone marrow stem cell. *Erythropoiesis-* - Differentiation of stem cell into a mature erythrocyte (RBC), through a series of intermediates. - Reticulocyte = immature RBC - Strongly stimulated by tissue hypoxia (low O2 concentration) - Erythropoietin (formed by synthetic products of the liver and kidneys, and α- globulin) stimulates formation of stem cells that give rise to RBCs. - Takes 3-5 days to make new RBCs. - Worn out RBCs removed by maqcrophages, especially in the spleen. - Erythroclasia (removal of RBCs) should be in balance with erythropoiesis. - Approximately 2 million new RBCs produced every minute. *Process:* (red blood cell formation)* - Rubriblast -> Prorubricyte -> Rubricate -> Metarubricyte -> Reticulocyte -> Erythrocyte - *Approximately 2.5 billion RBC's (*Human) produced per day with an average life span of approximately 120 days - *Process is controlled by availability of iron, folic acid, vitamin B12 and protein precursors *Granulocytopoiesis-* - Formation of specific stem cells that differentiate into mature neutrophils, eosinophils, and basophils, through a series of intermediates. - Neutrophils develop within 5 days; 3-5 day lag time in production after stimulation of bone marrow - Circulating pool of neutrophils have a half life of 6 days. - Marginal pool of neutrophils lines the interior of blood vessels; the number of neutrophils in this pool may be equal or greater than the circulating pool. - Neutrophils of circulating and marginal pools eventually enter tissue. - Half of circulating neutrophils leave the circulation and enter tissue every 6-8 hours. - Neutrophils survive in tissue for 1-2 days, then removed by macrophages - *Eosinophils-* --- Maturation similar to that of neutrophils --- Takes 3-6 days --- 300 cells in the maturation pool for every circulating cell --- 100 cells in proliferating pool (bone marrow?) for every circulating cell. - *Basophils-* --- Maturation similar to neutrophils and eosinophils *Process:* (formation of basophils, eosinophils, neutrophils) Myeloblast -> Promyelocyte -> Myelocyte (basophilic, eosinophilic, neutrophilic) -> Metamyelocyte (basophilic, eosinophilic, neutrophilic) -> Basophil (*1-2% of WBC's; 21⁄2 days to form; short lived) or Eosinophil (*1-8% of WBC's {species dependent}; 3-6 days to form; live 8-12 days) or Neutrophil (*24-72% of WBC's {species dependent}; 5 days to form; live 6 hours to a few days) *Agranulocytopoiesis-* - formation of specific stem cells that differentiate into mature monocytes and lymphocytes, through a series of intermediates. - *Monocytopoiesis-* --- Monocytes develop from a stem cell in bone marrow --- Circulates for 3-4 days, then enters tissue *Process:* (Formation of monocytes/macrophages) Mono blast -> Promonocyte -> Monocyte (*5-9% of WBC's {species dependent}; 2-3 days to form; live months-years; circulate in blood for 3-4 days before migrating into tissues under influence of chemotactic factors; majority of cells die of apoptosis unless stimulated by growth factors {IL-3, M-CSF, GM-CSF) -> Macrophage *(differentiated fixed tissue monocytes {histiocytes}; live months-years after stimulation by growth factors {IL-3, M-CSF, GM-CSF}; become APC's after stimulation by interferon-Ɣ) - *Lymphocytopoiesis-* --- Lymphocytes arise from a common stem cell in bone marrow --- Some migrate to thymus where they develop into T lymphocytes --- Some mature in bone marrow, then migrate to spleen, lymph nodes, lymphatic nodules as B lymphocytes *Process:* (lymphopoiesis = formation of lymphocytes)* Lymphoblast (*largest cell; progressive decrease in size with differentiation) -> <- Small lymphocyte (*cells of spleen, bone marrow, and lymph nodes formed over several days) -> Medium lymphocyte (*cells of spleen, bone marrow, and lymph nodes formed within 8 hours) -> Large lymphocyte (*cells of spleen, bone marrow, and lymph nodes formed within 8 hours) --- *(Lymphocyte size is a function of activity; extensive recirculation of Lymphocytes in blood and lymph; ) *Thrombocytopoiesis-* - formation of specific stem cells that differentiate into megakaryocytes, through a series of intermediates. Platelets are formed by "pinching off" of cytoplasm from megakaryocytes. - *Approximately 2-2.5 billion platelets produced Daily (humans), with an average life span of 8-12 days. Production can be increased ten fold if needed.

*Hematopoiesis:*

- Development of peripheral blood cells from a common bone marrow stem cell. - Erythropoiesis --- Differentiation of stem cell into a mature erythrocyte (RBC), through a series of intermediates. --- Reticulocyte = immature RBC --- Strongly stimulated by tissue hypoxia (low O2 concentration) --- Erythropoietin (formed by synthetic products of the liver and kidneys, and α- globulin) stimulates formation of stem cells that give rise to RBCs. --- Takes 3-5 days to make new RBCs. --- Worn out RBCs removed by maqcrophages, especially in the spleen. --- Erythroclasia (removal of RBCs) should be in balance with erythropoiesis. --- Approximately 2 million new RBCs produced every minute.

*Clinical Conditions:* *Polycythemia-*

- Elevated numbers of RBCs --- genetic disorders --- chronic hypoxia --- high altitudes --- tumors that secrete erythropoietin

*Hematopoiesis:* *Granulocytopoiesis-* - Eosinophils - Basophils

- Eosinophils --- Maturation similar to that of neutrophils --- Takes 3-6 days --- 300 cells in the maturation pool for every circulating cell --- 100 cells in proliferating pool (bone marrow?) for every circulating cell. - Basophils --- Maturation similar to neutrophils and eosinophils

*Blood Proteins:* *Coagulation proteins-*

- Fibrin - Fibrinogen

*White Blood Cells:* *Leukocytes-*

- Granulocytes (single multilobulated nucleus; contain prominent, type-specific cytoplasmic secretory granules) • Neutrophils • Eosinophils • Basophils - Mononuclear leukocytes (single non-lobulated nucleus) • Lymphocytes • Monocytes

*Coagulation Disorders:* *Congenital-*

- Hemophilia = a deficiency of one or more clotting factors. It can be treated with administration of fresh or fresh-frozen plasma. - Von Willebrand's disease = a deficiency of von Willebrand's factor. It can be treated with the administration of fresh or fresh-frozen plasma.

*White Blood Cells:* *Basophil-*

- Intermediate in size between neutrophils and eosinophils - Bilobed nucleus which is obscured by dark staining basophilic granules (contain proteoglycans, histamine, slow reacting substance of anaphylaxis, eosinophil chemotactic factor of anaphylaxis, tryptase {highly water soluble}. - Least populous white blood cell. - Function in immediate hypersensitivity (anaphylactic) reactions, allergic dermatitis, and skin allograft rejection. - Average life span is unknown

*White Blood Cells:* *Monocyte-*

- Largest of the white blood cells (16-25 microns in diameter). - Large eccentrically placed nucleus with an indentation (horse shoe - kidney bean shape). - Lighter stained nucleus than other white blood cells. - Migrates into tissues from the blood (chemotaxis) to become macrophage. - Extensive greyish-blue cytoplasm - Cytoplasmic granules contain myeloperoxidase, acid phosphatase, elastase, cathepsin-G, plasma proteins, membrane adhesion proteins, tumor necrosis factor alpha - Continuous lysosomal activity and regeneration utilizing aerobic and anaerobic pathways.

*Red Bone Marrow:* Composition- *Hematopoieticcompartment:*

- Meshwork of reticular fibers and reticular cells extend between vessels of vascular compartment forming irregular islands of tissue - Collagen fibers, laminin, fibronectin, proteoglycans - Cells: --- Reticular cells --- Stem cell (CFU-S = colony forming unit spleen; a pluripotent stem cell giving rise to all other cell lines) of lymphocytes (CFU- BL; CFU-TL), RBC's (CFU-E), granulocytes & monocytes (CFU-GM), megakaryocytes (CFU-Meg), eosinophils (CFU-EO) --- Adipocytes --- Monocytes/Macrophages --- Lymphocytes (T cells, B cells, plasma cells) - Mast cells --- Megakaryocytes --- Platelets --- Neutrophils --- Basophils --- Eosinophils

*Hematopoiesis:* *Agranulocytopoiesis-* - Monocytopoiesis - Lymphocytopoiesis

- Monocytopoiesis --- Monocytes develop from a stem cell in bone marrow • Circulates for 3-4 days, then enters tissue - Lymphocytopoiesis --- Lymphocytes arise from a common stem cell in bone marrow --- Some migrate to thymus where they develop into T lymphocytes --- Some mature in bone marrow, then migrate to spleen, lymph nodes, lymphatic nodules as B lymphocytes

*Blood Proteins:*

- Most plasma proteins except gamma globulins (*produced by lymphocytes) are synthesized by the liver. - Plasma proteins as a group maintain intravascular plasma osmotic pressure which regulates fluid exchange between plasma and the extracellular space.

*White Blood Cells:* *Neutrophil-*

- Most populous granulocyte in circulating blood (40- 75%) and connective tissue - 9-14 microns in diameter (species dependent) - multilobulated nucleus ("drum stick appendage" present in some peripheral blood neutrophils of the female = condensed, quiescent X chromosome or Barr body) - Granules contain lysosomal enzymes, bacteriacidal substances, alkaline phophatase - Highly phagocytic - Present in acute infections ("pus" = dead neutrophils) - Average life span = 6 hours to a few days.

*White Blood Cells:* *Lymphocyte-*

- Mostfrequentlyencounteredagranulocyte. - A round cell with a densely stained nucleus and a relatively small amount of pale bluish (basophilic) staining cytoplasm. - Small (6-9 microns in diameter) and large (12-15 microns in diameter) cells make up 97% (inactive) and 3% (active) of the respective lymphocyte population. - Travels throughout circulation, populates lymphoid organs, migrates into tissues, functions in immune surveillance. - Average life span as a group is undetermined (*depends on specific type of lymphocyte).

*Bone Marrow:* General composition-

- Network of reticular fibers and reticular cells containing red and white blood cell stems cells, developing red and white blood cells, phagocytic cells, lymphocytes, mast cells, adipocytes, megakaryocytes, and platelets interposed as irregular cords between arteries, veins, and sinuses of medullary cavity. - Medullary cavity = space between endosteum of cortical bone (includes trabecular bone and its endosteal layer).

*Written Objectives:* 1. Describe the morphology and function of erythrocytes, neutrophils, eosinophils, basophils, monocytes, lymphocytes, platelets, and megakaryocytes, and their role in health and homeostasis.

- Numerous cells are found in blood --- Blood cells are categorized as erythrocytes (RBCs) and leukocytes (WBCs) --- Leukocytes are further designated as granulocytes or Granulocytes --- All blood cells arise from stem cells within bone marrow and then migrate to the vascular system to enter the blood. *Erythrocytes-* *Morphology:* - Origin = Bone marrow stem cell - Size = 3.5-7.5 microns (species dependent) - Life Span = 120 days - Description = --- Biconcave, enucleated (*nucleated in certain species, e.g. birds, fish, reptiles), round disc in most species ------ Biconcave shape places hemoglobin molecules closer to the RBC plasma membrane, which facilitates gas exchange. ------ In camels and llamas = the cells are elliptical in shape --- Millions of RBCs - Stains red to pink in routine histological sections - Dead or worn out cells are removed by macrophages in the spleen, liver, and bone marrow - Specialized cytoskeleton which allows for elasticity and changes in shape to compensate for mechanical forces encountered during circulation. - have surface bound glycoproteins --- The carbohydrate portion of the glycoprotein is distinct and provides the basis for ABO blood grouping system --- Another glycoprotein system associated with RBCs is the Rh system *Function:* - Contains high concentration of hemoglobin for transporting oxygen and carbon dioxide --- Hemoglobin (Hb) ------ 68 kDa protein ------ Binds to CO2 and O2 (1Hb can bind to 4O2) ------ High concentrations of Hb in RBCs ------ 96% of HB in adults is HbA ------ 8% of HbA is subtype HbA1c; HbA1c binds irreversibly to glucose and is used to monitor blood glucose levels (A1c test); Diabetics have increased A1c levels (*any A1c level above 6.0 requires medication) *Neutrophils-* Morphology: - (heterophils or polymorphonuclear leukocytes) - Origin = Bone marrow stem cell - Size = 9-14 microns in diameter (species dependent) - Life Span = 6 hrs-few days. - Type of leukocyte (granulocyte) - Most populous granulocyte in circulating blood (40- 75%) and connective tissue --- Most numerous white blood cells except in ruminants, laboratory rodents, and birds, where lymphocytes predominate. - Single multilobulated nucleus --- "drum stick appendage" present in some peripheral blood neutrophils of the female = condensed, quiescent X chromosome or Barr body ------ (Neutrophils of females possess a single drum-stick shaped appendage on one of the nuclear lobes:) - Cytoplasmic granules --- Contain lysosomal enzymes, bacteriacidal substances, alkaline phosphatase *Function:* - Highly phagocytic --- Present in acute infections ("pus" = dead neutrophils) - Highly mobile and serve as the first group of cells to enter an area of tissue damage. --- Enter tissue at post-capillary venues --- Form interactions with endothelial cells through surface adhesion molecules (E-selectins, P-selectins) which causes them to slow their movement and roll along the surface of the venule --- Cells eventually become tightly bound to the endothelial cell lining. --- Next, neutrophils enter damaged tissue by migrating between intercellular junctions. ------ They form transient cytoplasmic extensions called pseudopodia, which pull them along tissue surfaces. ------ Vasodilating substances (heparin, histamines) are released by perivascular mast cells, which increases the spaces at the intercellular junctions. ------ Chemotactic substances released from tissue injury stimulate neutrophil migration. --------- Movement of neutrophils out of the circulation is known as leukocyte extravasion (diapedesis). ------ Once at the injury site, neutrophils bind directly or indirectly with the antigenic material. --- Next, the neutrophil engulfs the antigen, placing it into a cytoplasmic sphere called a phagosome. ------ Neutrophils contain three main types of cytoplasmic granules: --------- Primary (azurophilic) granules or lysosomes contain bactericidal compounds such as myeloperoxidase, acid hydrolases, defensins, and cathelicidin. --------- Secondary (specific) granules contain enzymes including elastase, collagenase, complement activators, and additional antimicrobials such as lysozomes and lactoferrins. --------- Tertiary granules contain phosphates and metalloproteinases. --- The cytoplasmic membrane encompassing neutrophil intracellular granules fuse with the phagosome, bringing its contents into contact with the antigenic material. --- During this process, neutrophil glucose and oxygen utilization increases dramatically in a phenomenon known as the respiratory burst. --- Neutrophils die during the process of phagocytosis and bacterial killing, forming a thick white to yellow-green exudate at the injury site called pus. *Eosinophils-* *Morphology:* - Origin = Bone marrow stem cell - Size = 12-17 microns (species dependent) - Life Span = 8-12 days - Description = Bilobed nucleus, 1- 4% of WBCs - Acidophilic granules --- contain major basic protein, other basic proteins, lysosomal enzymes, eosinophil peroxidase --- *can identify domestic animal species based on morphology of granules - Second most populous granulocyte in connective tissue --- (*diurnal variation = more cells in morning versus afternoon). - Increased numbers in parasitic infections, allergic reactions, extracellular spaces at sites of antigen/antibody reactions. - Phagocytic (less so than neutrophils). - Contain multilobed nuclei and are especially large in horses - Also contain primary and secondary granule --- primary granules are called lysosomes ------ contain several lysosomal acid hydrolases and other hydrolytic enzymes. --- Secondary granules- ------ contain crystalloid bodies which give the cell its representative refractivity when viewed with light microscopy ------ also contain histaminase (neutralizes histamine), arylsulfatase, collagenase, and cathepsins - Contain four main proteins including major basic protein --- (MBP- responsible for acidophilic staining of granules; strongly cytotoxic to protozoans and helminthic parasites), --- Eosinophil cationic protein (ECP- strongly cytotoxic to protozoans and helminthic parasites) --- Eosinophil peroxidase (EPO- strongly cytotoxic to protozoans and helminthic parasites) --- Eosinophil-derived neurotoxin (EDN- responsible for nervous system dysfunction in parasitic organisms) *Function:* - Phagocytic (parasites, allergic rxns, Ag/Ab runs) - Eosinophils are activated through interactions with IgE, IgA, or secretory IgA antibodies. --- Increase during allergic reactions and parasitic infections, and they phagocytize antigen-antibody complexes. --- Decrease in numbers in conditions leading to reflex stimulation of the adrenal cortex, sympathomimetic drugs, retinal irritation, and any stress mechanism. *Basophils-* - Origin = Bone marrow stem cell - Size = 10-15 microns - Life Span = unknown - Description = Bilobed nucleus, basophilic granules - Bilobed nucleus: --- Which is obscured by dark staining basophilic granules (contain proteoglycans, histamine, slow reacting substance of anaphylaxis, eosinophil chemotactic factor of anaphylaxis, tryptase {highly water soluble}. --- The high concentration of sulfated proteoglycan molecules of heparin give the secondary granules dark blue staining, which often obscures the nucleus. ------ Heparin is a vasodilator - Least populous white blood cell (0.5-2% of WBCs) - Intermediate in size between neutrophils and eosinophils - Primary granules: --- contain several acid hydrolases associated with other leukocytes - Secondary granules: --- contain numerous substances including heparin, histamine, heparin sulfate, leukotrienes, and interleukins 4 and 13. In fact, basophils are the primary source of histamine in normal blood *Function:* - Hypersensitivity reactions (Anaphylactic / Anaphylaxis), allergic dermatitis, Skin autograft rejection - Leukotrienes are responsible for triggering prolonged smooth muscle contraction in airways. - Interleukin 4 and 13 stimulate production of IgE antibodies. - Basophils are active in allergic reactions and parasitic diseases. --- When stimulated, they release vasoactive substances from their granules. ------ These substances are associated with sever hypersensitivity reactions and anaphylaxis - Also have a phagocytic function. *Monocytes-* - Origin = Bone marrow stem cell - Size = 16-25 microns (Largest of the white blood cells in peripheral blood) - Life Span = 3 days in blood - Description = eccentric lighter- staining nucleus, grey-blue cytoplasm, 2-6% of WBCs - Large eccentrically placed nucleus with an indentation (horse shoe - kidney bean shape). - Lighter stained nucleus than other white blood cells. - Extensive grayish-blue cytoplasm - Cytoplasmic granules contain myeloperoxidase, acid phosphatase, elastase, cathepsin-G, plasma proteins, membrane adhesion proteins, tumor necrosis factor alpha - have abundant, weakly basophilic staining cytoplasm that often has pseudopodia - Although classified as agranular, the cytoplasm contains fine granules, and the nucleus is often indented on one side giving the cell a kidney bean or horse-shoe shape --- The nucleus can appear clover-leaf-shaped in cattle and horses. It can be difficult to discern young monocytes from large lymphocytes. Monocytes are highly motile and phagocytic *Function:* - Phagocytic activity, lysosomal activity - Continuous lysosomal activity and regeneration utilizing aerobic and anaerobic pathways. - Migrates into tissues and organs from the blood (chemotaxis) to transform into macrophage. --- The monocyte-macrophage is an antigen presenting cell that interacts with helper CD4 lymphocytes through MHC II molecules on the monocyte-macrophage surface. --- This is an important part of cell-mediated immunity. *Lymphocytes-* - Origin = Bone marrow stem cell or an equivalent organ (Bursa of Fabricous- birds) in other species - Size = Small (6-9 microns in diameter) and large (12-15 microns in diameter) cells make up 97% (inactive) and 3% (active) of the respective lymphocyte population. - Life Span = Unknown (*depends on specific type of lymphocyte) - Description = Large dark, spherical nucleus, basophilic cytoplasm, 20-50% of WBCs - Lymphocytes typically contain a large spherical nucleus surrounded by a thin layer of basophilic cytoplasm - A round cell with a densely stained spherical nucleus and a relatively small amount of pale bluish (basophilic) staining cytoplasm. - Most frequently encountered granulocyte. - Three broad categories of lymphocytes are recognized: --- T lymphocytes ------ In human blood, 60-80% of lymphocytes are mature T lymphocytes ------ Enter the blood and travel to the thymus where they are programmed. ------ Found in the thymus, paracortical zones of lymph nodules and the periarteriolar region of splenic corpuscles ------ Life span varying between hours and years --------- Longer lived cells are most likely memory T cells. --- B lymphocytes, ------ In human blood, 20-30% are mature B lymphocytes ------ Found in bone marrow, the bursa of Fabricius (birds), germinal centers of lymph nodules, and in splenic follicles ------ Have a variable life span --------- Longer lived cells are most likely memory B cells. ------ Involved in humoral immunity. --- Natural killer (NK) cells ------ In human blood, remaining lymphocyte % ------ Differentiated by their surface markers CD16, CD56, and CD94 ------ usually larger than B and T cells (15 um) ------ have kidney bean-shaped nuclei ------ Contain large primary granules, which can be seen with light microscopy ------ Programmed to kill certain virus-infected cells and some tumor types ------ Secrete a powerful antiviral compound called gamma interferon. *Fuction:* - Travels throughout circulation, populates lymphoid organs, migrates into tissues, functions in immune surveillance. *Platelets-* - (thrombocytes) - Origin = Formed by the release of small bits of cytoplasm from large polynucleated cells in bone marrow called megakaryocytes - Size = 1.5-3.5 microns - Life Span = Unknown - Description = Round/oval biconcave discs, purple staining, granular appearance. - 1,500 - 436,00/liter - Granules contain membrane adhesion molecules, coaglution factors, lysosomal enzymes, peroxidase activity. - not actually cells but small discoid structures *Function:* - Function in blood clotting (*most important), vascular repair, vasoconstriction, opsonization (combine with bacteria). - Essential for proper hemostasis (control of bleeding) and tissue repair. --- These cells circulate through the vascular system monitoring injury to the endothelial lining of blood vessels. --- Areas of damage cause platelet adhesion to the injury site and release of substances needed for repair. --- Platelets contain serotonin (a potent vasoconstrictor), ADP, thromboxane A2 (stimulated further platelet aggregation), growth factors (platelet derived growth factor), and coagulation factors. --- At this point, a primary hemostatic plug is formed. --- The aggregated platelets provide a surface for the conversion of circulating fibrinogen into fibrin, which forms a dense meshwork of fibers that entraps additional platelets and some RBCs. --- A secondary hemostatic plug (clot) is now formed. ------ Platelets within the clot retract after the repair has been accomplished to restore proper blood flow, and the clot is degraded and removed through the action of plasmin (generated from a soluble pro-enzyme of circulating blood called plasminogen) and tissue plasminogen activator (TPA) released form endothelial cells. *Megakaryocytes-* - Origin = Found in Bone marrow / arise from a stem cell that differentiates from the pluripotent stem cell - Size = 30-100 microns - Life Span = Unknown - Description = - a large polyploid cell with a large irregular multi lobular nucleus - fine basophilic granules *Function:* - cytoplasmic fragments form platelets that enter the circulation. - During development --- These cells undergo as many as seven replications of nuclear and cytoplasmic materials ------ Resulting in large cells with multiple sets of chromosomes, lobulated nuclei, and extensive cytoplasm. ------ Megakaryocytes pinch off small discs of cytoplasm from the cell surface to form platelets.

*Clinical Tests:* (6)

- Red Blood Cell Count --- Total number of RBCs in a sample of blood ------ adulthumanmales-5.4millionRBCs/mm3 ------ adulthumanfemales-4.8millionRBCs/mm3) - Hematocrit (HCT or packed cell volume) --- It is the % of RBC volume - Hemoglobin (Hgb) --- hemoglobin concentration indicates ability of RBCs to carry O2 ------ adult human male = 14-18g/dL ------ adult human females = 12-15g/dL - Mean Corpuscular Volume (MCV) --- an indicator of RBC size - Mean Corpuscular Hemoglobin (MCH) --- amount of hemoglobin in an average RBC - Mean Corpuscular Hemoglobin Concentration (MCHC) --- % of hemoglobin in an average RBC

*Blood Components:* *Cells-*

- Red blood cells (RBCs) --- Erythrocytes - White blood cells (WBCs) --- Leukocytes - Platelets --- Thrombocytes

*Bone Marrow:* General composition- *Types-*

- Red bone marrow • Found in all bones of young individuals • Primarily restricted to vertebrae, ribs, sternum, and cranial bones of adults • Highly vascular, contains numerous RBC's and copious amounts of hematopoietic (blood forming) tissue - Yellow bone marrow • Less vascularized • Adipose tissue replaces most of the hematopoietic (blood forming) tissue; can revert to red marrow under certain stress conditions.

*Red Blood Cells:* Blood Grouping (typing)

- Surface of RBCs contain genetically determined proteins (antigens, agglutinogens or isoantigens). - Responsible for the ABO and Rh blood grouping systems.

*White Blood Cells:* *Eosinophil-*

- The next most populous granulocyte in connective tissue (*diurnal variation = more cells in morning versus afternoon). - 12-17 microns in diameter (species dependent). - Bilobed nucleus - Acidophilic granules (contain major basic protein, other basic proteins, lysosomal enzymes, eosinophil peroxidase)(*can identify domestic animal species based on morphology of granules). - Increased numbers in parasitic infections, allergic reactions, extracellular spaces at sites of antigen/antibody reactions. - Phagocytic (less so than neutrophils). - Average life span = 8-12 days.

*Coagulation Disorders:* *Sequelae of DIC - Hypoxia-*

- Tissue death - Release of tissue factor - Severe clotting - Use up all available clotting factors - Severe hemorrhage (death)

*Clinical Correlation:* *Hemolytic Transfusion Reaction-*

- Transfusing a patient with an incompatible type of blood (e.g. transfuse blood group A blood into a patient with blood group B blood) - Antibodies within the patients blood destroy the B - RBCs of the transfused blood. - *Life threatening condition - *Blood for transfusion is always cross- matched, even if the patient's blood type is listed.

*Coagulation Disorders:* *Disseminated intravascular coagulopathy (DIC)*

- an overwhelming activation and consumption of clotting factors and platelets, followed by enhanced fibrinolysis. *It is always a secondary condition caused by wide spread tissue damage and endothelial cell injury (e.g. burns, heat shock, severe trauma, and wide spread tumor metastasis).

*Clinical Conditions:* *Sickle Cell Anemia-*

- caused by a single point mutation in the gene encoding β- globulin chain of hemoglobin A. - Get substitution of valine for glutaminc acid. - Causes hemoglobin molecules to aggregate and grow in length beyond the limits of a normal RBC, under low O2. - Sickle-shaped RBCs are more rigid, and adhere to the endothelial surface which clogs vessels. Pain; damage to tissues due to poor oxygen saturation. Sickle-shaped RBCs have a short life span (10-20 days). Sickling process is reversible, and occurs when O2 saturation drops (below 85% = homozygotes; below 40% = heterozygotes).

*Hematopoiesis:* *Agranulocytopoiesis-*

- formation of specific stem cells that differentiate into mature monocytes and lymphocytes, through a series of intermediates.

*Hematopoiesis:* *Thrombocytopoiesis-*

- formation of specific stem cells that differentiate into megakaryocytes, through a series of intermediates. Platelets are formed by "pinching off" of cytoplasm from megakaryocytic. - *Approximately 2-2.5 billion platelets produced Daily (humans), with an average life span of 8- 12 days. Production can be increased ten fold if needed.

*Bone Marrow Cells:* *Megakarocyte-*

- found in bone marrow - a large polyploid cell (30-100 microns in diameter) with a large irregular multi lobular nucleus - fine basophilic granules - cytoplasmic fragments form platelets that enter the circulation.

*Serum:*

- plasma which has had fibrin and fibrinogen removed

*Red Bone Marrow:* Composition- *Vascular compartment-*

-Medullary arteries, veins, and sinuses --- Continuous endothelial lining --- Discontinuous basement membrane

*Written Objectives:* 2. Describe clinical tests and conditions associated with blood as presented in class.

Clinical Conditions: *Polycythemia:* - Elevated numbers of RBCs --- genetic disorders --- chronic hypoxia --- high altitudes --- tumors that secrete erythropoietin *Anemia:* - Decrease in the amount of Hemoglobin (Hb) in the blood (Low = <15.g/dl for males and <12 g/dl for females) --- External and internal hemorrhage --- Poor nutrition --- Iron and vitamin B12 deficiencies --- Chronic diseases --- Pregnancy - Anisocytosis --- Alterations in the normal size of RBCs *Sickle Cell Anemia:* - caused by a single point mutation in the gene encoding β- globulin chain of hemoglobin A. - Get substitution of valine for glutaminc acid. - Causes hemoglobin molecules to aggregate and grow in length beyond the limits of a normal RBC, under low O2. - Sickle-shaped RBCs are more rigid, and adhere to the endothelial surface which clogs vessels. Pain; damage to tissues due to poor oxygen saturation. Sickle-shaped RBCs have a short life span (10-20 days). Sickling process is reversible, and occurs when O2 saturation drops (below 85% = homozygotes; below 40% = heterozygotes). Clinical Tests: *Red Blood Cell Count-* - Total number of RBCs in a sample of blood --- adulthumanmales-5.4millionRBCs/mm3 --- adulthumanfemales-4.8millionRBCs/mm3) *Hematocrit (HCT or packed cell volume)-* - It is the % of RBC volume *Hemoglobin (Hgb)-* - hemoglobin concentration indicates ability of RBCs to carry O2 --- adult human male = 14-18g/dL --- adult human females = 12-15g/dL *Mean Corpuscular Volume (MCV)-* - an indicator of RBC size *Mean Corpuscular Hemoglobin (MCH)-* - amount of hemoglobin in an average RBC *Mean Corpuscular Hemoglobin Concentration (MCHC)-* - % of hemoglobin in an average RBC *White Blood Cell (WBC) Count-* - Number of all WBCs in a sample. - Normal human WBC count = 5,000-9,000 WBCs/mm3 *Differential White Blood Cell Count-* - Individual numbers of neutrophils (mature and immature), basophils, eosinophils, monocytes, and lymphocytes in a blood sample. *Leukocytosis(human)-* - Greater than 10,000 WBCs/mm3 (e.g. illness, infection, burns, fractures, other injuries, post- exercise, pregnancy, and labor) *Leukopenia (human)-* - Less than 5,000 WBCs/mm3 (e.g. radiation and chemotherapy treatments, anemia, autoimmune diseases, bone marrow diseases, anti-epileptic and anti-psychotic drugs, HIV, AIDs). *Thrombocythemia-* - high number of platelets (e.g. proliferative disorders of bone marrow, inflammation, decreased spleen function or splenectomy). *Thrombocytopenia-* - low number of platelets (e.g. hereditary syndromes, leukemia, infections, vitamin B12 deficiency, autoimmune diseases, genetic disorders, DIC).

*Written Objectives:* 5. Describe the mechanism of blood clotting and related clinical conditions.

Coagulation Proteins: - Fibrin - Fibrinogen Prevention: - 1. Endothelial cells produce heparin-like surface molecules that inactivate thrombin (*catalyzes the conversion of fibrinogen into fibrin) and some coagulation. - 2. Endothelial cells have surface thrombomodulin molecules that bind with circulating thrombin molecules to form the Protein C complex (*inactivates coagulation factors V, VIII) - 3. Tissue plasminogen activator (t-PA) synthesized by endothelial cells, breaks down fibrin and prevents platelet adhesion. Normal: - 1. Rupture of blood vessels causes immediate vasoconstriction. - 2. Exposed collagen fibers from damaged tissue attract platelets. Initial platelet binding to collagen is weak; von Willebrand's factor (*produced by endothelial cells) enhances platelet binding. - 3. Platelets that initially bind to collagen release compounds stored in their granules (ADP, ATP, ionic calcium, histamine, serotonin, epinephrine, fibrinogen, fibronectin, clotting factors V and VIII, growth factors, platelet factor 4, thromboxane A2). *Has the overall effect of slowing blood flow through vasoconstriction, and stimulating platelet adhesion. Results in the formation of a phospholipid complex (clotting cascade) on the surface of platelets that causes shape changes in platelets and release of substances from secretory granules - stimulates intrinsic coagulation pathway. - *Ca2+ required for coagulation • Binds negatively charged clotting factors of the coagulation cascade to the negatively charged phospholipid surface of platelets. - Vitamin B12 required for coagulation • Acts as a cofactor for a carboxylase produced in the liver. The carboxylase stimulates certain proteins to create Ca2+ binding sites. - 4. Additional aggregation of platelets, with the continuation of the intrinsic coagulation pathway. Fibrinogen and other compounds from platelet granules activates more platelets and enhances platelet binding. Platelets develop pseudopodia that extend into the injury site and between adjacent platelets. More platelets are added to the aggregate and a primary hemostatic plug (*water soluble) is formed. - 5. Damaged tissue releases tissue factor which activates the extrinsic coagulation pathway. Thrombin mediates the conversion of fibrinogen to fibrin (*insoluble). Activation of clotting factor X is the step in the clotting cascade that links the intrinsic and extrinsic pathways, and results in the formation of the secondary hemostatic plug. - 6. Clot retraction occurs as a result of complete fibrin polymerization. Actin and myosin are organized into contractile microfilaments that retract the clot, making it permanent. - 7. Tissue plasminogen activator secreted by endothelial cells converts plasminogen to plasmin (a protease), which breaks up the polymerized fibrin, once the tissue has been repaired. Secondary Hemostasis - Local activation of the coagulation cascade (involving tissue factor and platelet phospholipids) results in fibrin polymerization, "cementing" the platelets into a definitive secondary hemostatic plug The Coagulation Cascade - Note the common link between the intrinsic and extrinsic pathways at the level of factor IX activation. - Factors in red boxes represent inactive molecules; - Activated factors are indicated with a lower case 'a' and a green box. - PL = Phospholipidsurface; - HMWK = high molecular weight kininogen. - Not shown are the anticoagulant inhibitory pathways *Coagulation Disorders:* Congenital- - Hemophilia = a deficiency of one or more clotting factors. It can be treated with administration of fresh or fresh-frozen plasma. - Von Willebrand's disease = a deficiency of von Willebrand's factor. It can be treated with the administration of fresh or fresh-frozen plasma. Acquired- - Depression of clotting factors = may result from liver disease, vitamin K deficiency, coumarin toxicity, and DIC. DIC: - Disseminated intravascular coagulopathy - an overwhelming activation and consumption of clotting factors and platelets, followed by enhanced fibrinolysis. *It is always a secondary condition caused by wide spread tissue damage and endothelial cell injury (e.g. burns, heat shock, severe trauma, and wide spread tumor metastasis). - Mechanism of DIC- - 1. Thrombocytopenia (platelet supply is exhausted) - 2. Depletion of clotting factors (e.g. V, VIII, X, and fibrinogen) - 3. Activation of the fibrinolysis system (break down of fibrin by plasmin) - 4. Increased fibrin degradation products (have anti-coagulation properties because they compete for fibrinogen binding sites on the surface of platelets) - *Sequelae of DIC - Hypoxia-* --- Tissue death --- Release of tissue factor --- Severe clotting --- Use up all available clotting factors --- Severe hemorrhage (death) - Treatment of DIC- --- Administration of heparin (inhibits clotting; prevents patient from using up all clotting factors and platelets). --- Administration of normal plasma or whole blood. Lab guide: Platelets are essential for proper hemostasis (control of bleeding) and tissue repair. These cells circulate through the vascular system monitoring injury to the endothelial lining of blood vessels. Areas of damage cause platelet adhesion to the injury site and release of substances needed for repair. Platelets contain serotonin (a potent vasoconstrictor), ADP, thromboxane A2 (stimulated further platelet aggregation), growth factors (platelet derived growth factor), and coagulation factors. At this point, a primary hemostatic plug is formed. The aggregated platelets provide a surface for the conversion of circulating fibrinogen into fibrin, which forms a dense meshwork of fibers that entraps additional platelets and some RBCs. A secondary hemostatic plug (clot) is now formed. Platelets within the clot retract after the repair has been accomplished to restore proper blood flow, and the clot is degraded and removed through the action of plasmin (generated from a soluble pro-enzyme of circulating blood called plasminogen) and tissue plasminogen activator (TPA) released form endothelial cells.

*Major Types of Blood Protein:*

Coagulation proteins Albumin Globulins

*Written Objectives:* 7. Describe the structure, composition, and function of bone marrow.

From lab guide: bone marrow is found within the medullary cavities of bones. It can be subdivided into red and yellow marrow. Red bone marrow is highly concentrated in juveniles. It consists of arteries, veins, sinuses, a reticular fiber network, stem cells of red and white blood cell lineages, macrophages, and some adipose tissue. Yellow bone marrow is concentrated in adults. It contains a higher concentration of adipose tissue and fewer hematopoietic cells. Yellow bone marrow can be converted to red bone marrow in adults under stress conditions. A single pluripotent stem cell (PPSC) gives rise to other stem cells capable of differentiating into mature erythrocytes, leukocytes, lymphocytes, and platelets. Each specific stem cell goes through a series of changes (e.g. erythrocytic series - monocytes, lymphocytes; thrombocytic series - megakaryocytes, platelets) to become a mature blood cell. General Composition: - Network of reticular fibers and reticular cells containing red and white blood cell stems cells, developing red and white blood cells, phagocytic cells, lymphocytes, mast cells, adipocytes, megakaryocytes, and platelets interposed as irregular cords between arteries, veins, and sinuses of medullary cavity. - Medullary cavity = space between endosteum of cortical bone (includes trabecular bone and its endosteal layer). Types: - Red bone marrow • Found in all bones of young individuals • Primarily restricted to vertebrae, ribs, sternum, and cranial bones of adults • Highly vascular, contains numerous RBC's and copious amounts of hematopoietic (blood forming) tissue - Yellow bone marrow • Less vascularized • Adipose tissue replaces most of the hematopoietic (blood forming) tissue; can revert to red marrow under certain stress conditions. Function: • Production of RBC's and WBC's. • Production of B cells (*also site of B cell maturation) and T cells. • Removal of aged and defective RBC's. • Formation of platelets. Red Blood Marrow Composition: - Vascular compartment --- Medullary arteries, veins, and sinuses ------ Continuous endothelial lining ------ Discontinuous basement membrane - Hematopoietic compartment --- Meshwork of reticular fibers and reticular cells extend between vessels of vascular compartment forming irregular islands of tissue --- Collagen fibers, laminin, fibronectin, proteoglycans --- Cells ------ Reticular cells ------ Stem cell (CFU-S = colony forming unit spleen; a pluripotent stem cell giving rise to all other cell lines) of lymphocytes (CFU-BL; CFU-TL), RBC's (CFU-E), granulocytes & monocytes (CFUGM), megakaryocytes (CFU-Meg), eosinophils (CFU-EO) Cells ------ Adipocytes ------ Monocytes/Macrophages ------ Lymphocytes (T cells, B cells, plasma cells) ------ Mast cells ------ Megakaryocytes ------ Platelets ------ Neutrophils ------ Basophils ------ Eosinophils

*Written Objectives:* 6. Describe the composition and function of plasma in health and homeostasis.

Lab guide: plasma is the straw colored fluid component of blood. It consists of approximately 90% water and 10% dissolved substances and solids. Interstitial (tissue) fluid is a derivative of plasma. Plasma serves as a vehicle to transport nutrients, hormones, and other required substances and aids in eliminating waste. Dissolved substances include inorganic ions (Na+, K+, Cl-, HCO3-, Ca2+), protein (albumin, humoral antibodies, alpha globulins, beta globulins, gamma globulins), clotting factors (fibrinogen), organic compounds (urea, uric acid, amino acids, fatty acids, glycerol, etc.), hormones, pigments, enzymes, vitamins, and dissolved gases (CO2, O2). The protein component of plasma is very important. Albumin is a small protein accounting for almost half of all plasma proteins; it plays an important role in maintaining intravascular osmotic pressure. Alpha and Beta globulins support intravascular osmotic pressure. Gamma globulins consists of immunoglobulins and blood group globulins. From powerpoint: Fluid portion 90% water, 10% dissolved substances Solids Inorganic ions Na, K, Cl, HCO3, Ca, etc. = 1% Protein = 8% Function Transports nutrients, waste products, hormones Circulates immunoglubulins and cells of immune system Contains components of the clotting mechanism. - *serum = plasma which has had fibrin and fibrinogen removed - Most plasma proteins except gamma globulins (*produced by lymphocytes) are synthesized by the liver. - Plasma proteins as a group maintain intravascular plasma osmotic pressure which regulates fluid exchange between plasma and the extracellular space.

*Blood Components:* (4)

Plasma RBC WBC Platelets

*Types of Clinical Conditions in Blood:* (3)

Polycythemia Anemia Sickle Cell Anemia

*Hematopoiesis:* *Granulocytopoiesis-*

• Formation of specific stem cells that differentiate into mature neutrophils, eosinophils, and basophils, through a series of intermediates. • Neutrophils develop within 5 days; 3-5 day lag time in production after stimulation of bone marrow • Circulating pool of neutrophils have a half life of 6 days. • Marginal pool of neutrophils lines the interior of blood vessels; the number of neutrophils in this pool may be equal or greater than the circulating pool. • Neutrophils of circulating and marginal pools eventually enter tissue. • Half of circulating neutrophils leave the circulation and enter tissue every 6-8 hours. • Neutrophils survive in tissue for 1-2 days, then removed by macrophages.

*Bone Marrow:* General composition- *Function-*

• Production of RBC's and WBC's. • Production of B cells (*also site of B cell maturation) and T cells. • Removal of aged and defective RBC's. • Formation of platelets.

*Storage of Blood and Blood Products:* • Red Blood Cells - • Frozen Plasma - • Platelets -

• Red Blood Cells - 42 days • Frozen Plasma - 1 year • Platelets - 5 days