Agenda. Components of blood. Blood is Fluid Connective Tissue. Blood: General functions

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1 Agenda Chapter 19: Blood Major functions Major Components Structure of RBCs and WBCs ABO Blood Types, and Rh Factor Lab 34.1 and Blood Typing Blood: General functions Transport of dissolved gases, nutrients, hormones, and metabolic wastes Regulation of ph, ion composition of interstitial fluids Restriction of fluid loss at injury site Defense against toxins and pathogens Regulation of body temperature Blood is Fluid Connective Tissue Recall that connective tissues are comprised of: specialized cells, extracellular protein fibers and fluid (ground substance) Matrix is a combo of the non-celluar components The matrix of blood is called plasma Components of blood Plasma ~ 90% water ~ 10% dissolved (soluble) proteins most made by the liver Formed elements (cells and cell fragments) 1. RBCs 2. WBCs 3. Platelets 1

2 Plasma proteins Albumins (60%) -major component of osmotic pressure of plasma Formed Elements: Hematocrit Percent of blood volume contributed to formed elements (cells) Globulins (35%) -antibodies and transport proteins Fibrinogens (4%) -functions in blood clotting Centrifuge: separate components by density 2

3 Hematocrit Males ~ 46, Females ~ 42 What can effect hematocrit?!: Dehydration and EPO (erythropoietin), testosterone ": Internal bleeding, or defect in RBC formation When you look at a smear of blood, which cells predominate?? RBCs Characteristics 20 µm Function primarily to carry oxygen and CO 2 -contain hemoglobin (33% of cell weight) Lack a nucleus Contain few organelles (no mitochondria) Can they generate ATP?? Make new protein? Shaped like biconcave discs -increases surface area for gas exchange Life span approx. 120 days FYI: 1 µl of blood = ~ 5 million RBCs 1 drop of blood = ~ 260 million RBCs 3

4 Red Blood Cells Hemoglobin ~ 0.8 µm ~ 2.6 µm µm Increased surface area, stackable, and flexible (can fit through 4 µm capillaries) Composed of globin (protein) and pigment (heme) -Protein portion: 2 # and 2 $ chains -Four heme units: contain iron and bind oxygen Hemoglobin Hematopoiesis Rate of RBC production controlled by erythropoietin (EPO) Myeloid stem cell Quaternary Structure EPO produced by kidneys (upon exposure to low O 2 ) EPO acts on stem cells of red bone marrow, and!rate of maturation What is necessary for healthy RBCs? 4

5 Fate of RBCs Life span of days In 1 min: travel from periphery, are squeezed through capillaries, sent to heart and back! Become trapped in the spleen (eaten by macrophage) -heme degraded to biliverdin (green) -biliverdin converted to bilirubin (orange-yellow) -bilirubin binds to albumin, transported to liver for excretion in BILE At large intestine, bacteria convert bilirubin to urobilinogens and stercobilinogens urobilins and stercobilins ABO Blood Types ABO Blood Types ABO system refers to the presence of surface antigens on the RBCs AND the antibodies in the plasma Antigens also called agglutinogens Antibodies called agglutinins Type A Type B Type AB Type O For a person with type A blood, the A antigens (surface proteins) inform the body s defense system that A is self. For a persone with type A blood, which antigen(s) would alert the body as non-self or foreign? 5

6 ABO Blood Types Blood Types Type A Type B Type AB Type O When the body encounters foreign material, it generates antibodies against the surface antigens. When foreign RBC antigens are covered with antibodies, they clump and lyse (agglutination and hemolysis). What antibodies will each blood type have in the plasma? Rh Factor and Hemolytic Disease of the Newborn 6

7 Fetal cells enter mother s circulation Second pregnancy is attacked by maternal antibodies White Blood Cells (Leukocytes) Complete cells with nuclei and all organelles Fewer than RBCs ( /ul) Critical to the body s defense (immune system) Special features - Can migrate out of bloodstream - Capable of amoeboid movement -Atracted to specific chemical stimuli (respond by positive chemotaxis) -Capable of phagocytosis (Neutrophils, Eosinophils, Monocytes) 7

8 Neutrophils Eosinophils Basophils Monocytes Lymphocytes Types of WBCs granulocytes agranulocytes Note that many of these cells have names that reflect the way these cells look when under the scope, when stained with certain dyes Neutrophils Account for 50-70% of circulating WBCs Dense segmented nucleus with 2-5 lobes Highly mobile, often the first to arrive on the scene following injury Attack bacteria coated with antibodies While active, release prostaglandins and leukotrienes 2-4% of WBCs Stain red, 2 lobed nucleus Attack cells coated with antibodies Importantly, protect against parasites via exocytosis of toxic compounds Eosinophil Less than 1% Granules contain histamine, heparin Release enhances inflammation Basophils 8

9 2-8% of WBCs Remains in blood for 24hr before becoming a macrophage in tissue Monocytes Macrophage=aggressive phagocytes While active, secrete chemicals that attract/stimulate other WBCs Also secrete chemicals that attract fibroblasts into region 20-30% of WBCs Note the round nucleus, little cytoplasm Most lymphocytes reside in connective tissue or lymphatic organs In circulating blood: B cells, T cells, and NK cells Lymphocytes WBC Production Platelets Anuclear cell fragments, contain cytoplasm and proteins (4 µm diameter) Pinched off from megakaryocytes in bone marrow Major participant in clotting response 9

10 Hemostasis Highly regulated process of halting blood loss 3 phases 1. Vascular phase 2. Platelet phase 3. Coagulation phase Hemostasis: Vascular phase Release of ADP and endothelins Cutting triggers smooth muscle contraction of vessel wall Basal lamina exposed to bloodstream Endothelial cells release chemical factors, local hormones --ADP, endothelins Endothelial cell membranes become sticky --Platelets stick! Hemostasis: Platelet phase Hemostasis: Platelet phase

11 Hemostasis: Coagulation phase Fibrin is insoluble! 11