Blood

Functions A. Transport: gasses, nutrients, wastes, hormones, antibodies etc. B. Defense: Leukocytes- white blood cells (neutrophils, eosinophils, basophils, monocytes, lymphocytes) Antibodies: small proteins in blood Complement: small proteins in blood C. Regulation 1) Platelets form blood clots during injury & prevents excess blood loss. 2) Regulate body temperature w/ constricting/dilating blood vessels (circulation flow) 3) Salts & proteins keep content of water in plasma high (osmosis)- maintains blood pressure 4) Regulates pH & electrolytes in blood & interstitial fluid.

Serum: Blood plasma after clotting factors have been removed

Plasma A. Consists of inorganic & organic molecules dissolved in water. 55% of blood volume. water (90-92%), salts, gasses, hormones, vitamins, nutrients, cholesterol, antibodies. etc. B. plasma proteins: 1. albumin: 60%,most abundant & smallest. Mainly to maintain correct osmotic pressure of blood. 2. globulin: a) immunoglobuins= antibodies. b) Transport globulins: bind to insoluble substances that may be filtered out of kidney. 3. Fibrinogen inactive clotting factor . Activated form: fibrin.

Figure 20.1b The Composition of Whole Blood Plasma Proteins Other Solutes Albumins (60%) Major contributors to osmotic pressure of plasma; transport lipids, steroid hormones Electrolytes Normal extracellular fluid ion composition essential for vital cellular activities Ions contribute to osmotic pressure of body fluids Major plasma electrolytes are Na, K, Ca2, Mg2, Cl, HCO3, HPO4, SO42 Globulins (35%) Transport ions, hormones, lipids; immune function Fibrinogen (4%) Essential component of clotting system; can be converted to insoluble fibrin Organic nutrients Used for ATP production, growth, and maintenance of cells; include lipids (fatty acids, cholesterol, glycerides), carbohydrates (primarily glucose), and amino acids Regulatory proteins (1%) Enzymes, proenzymes, hormones Organic wastes Carried to sites of breakdown or excretion; include urea, uric acid, creatinine, bilirubin, ammonium ions 5

A pluripotent stem cell in red bone marrow 2 multipotent stem cells. A. Hemaotpoiesis- making of formed elements. Takes place in red bone marrow. A pluripotent stem cell in red bone marrow 2 multipotent stem cells. A multipotent stem cell maintains its population by replicating itself. Some of those new cells will differentiate into other types of stem cells. When a stem cell differentiates, it commits itself to a single developmental pathway. Leukemia: cancer of white blood cells. Too much production in bone marrow, but cells put out into blood are immature and not functional. Disrupts formation of normal blood cells.

Figure 20.8 The Origins and Differentiation of Formed Elements Pluripotential Stem Cells Red bone marrow Myeloid Stem Cells Lymphoid Stem Cells Progenitor Cells Blast Cells Proerythroblast Myeloblast Monoblast Lymphoblast Myelocytes Erythroblast stages Band Cells Ejection of nucleus Megakaryocyte Promonocyte Prolymphocyte Reticulocyte Erythrocyte Platelets Basophil Eosinophil Neutrophil Monocyte Lymphocyte Red Blood Cells (RBCs) Granulocytes Agranulocytes White Blood Cells (WBCs) 7

“Process of making formed elements (all blood cells)” Hematopoiesis “Process of making formed elements (all blood cells)” Multipotent

Figure 20.1c The Composition of Whole Blood (Part 2 of 2) Platelets White Blood Cells Red Blood Cells Neutrophils (50–70%) Eosinophils (2–4%) Monocytes (2–8%) Basophils (1%) Lymphocytes (20–30%) 9

Figure 20.2a Histology of Red Blood Cells Blood smear LM  477 When viewed in a standard histological blood smear, red blood cells appear as two-dimensional objects because they are flattened against the surface of the slide. 10

1. Erythrocytes a) Small biconcave disks- shape gives it flexibility to move through small capillaries and a large surface area (for diffusion of gasses) b) rouleau: stack of RBC’s in small spaces c) Enucleated- Survive 120 days in circulation, Destroyed in liver & spleen. d) Hemoglobin: (Hb) Four subunit protein. Each subunit contains 1 heme group. Each heme group contains an iron (Fe) atom which binds to oxygen. This is why we need iron in the diet! 280 million molecules of Hb in one RBC! - Anemia: condition where blood lacks enough healthy red blood cells or hemoglobin. - Causes of anemia: disease (eg. malaria), genetic disorder, low iron in diet. e) Hematocrit: % of RBC’s in blood. Normally about 45% for men and 40% for women f) ABO blood typing & Rh factor (D antigen)

Figure 20.2bc Histology of Red Blood Cells 0.45–1.16 m 2.31–2.85 m Red blood cells SEM  1838 7.2–8.4 m A scanning electron micrograph of red blood cells reveals their three-dimensional structure quite clearly. A sectional view of a red blood cell 12

Figure 20.2d Histology of Red Blood Cells Red blood cell (RBC) Rouleau (stacked RBCs) Nucleus of endothelial cell Blood vessels (viewed in longitudinal section) Sectioned capillaries LM  1430 When traveling through relatively narrow capillaries, erythrocytes may stack like dinner plates, forming a rouleau. 13

Figure 20.3 The Structure of Hemoglobin  chain 1  chain 1  chain 2 Heme  chain 2 Hemoglobin molecule Heme 14

Blood types- Erythrocyte antigens

Leukocytes (WBCs) Fight infection- in blood, lymph nodes, lymph & other lymphatic tissues. a) granular leukocytes 1.neutrophils* Polymorphonuclear (PMN), mobile, phagocytic, 2. eosinophils*: pink, kidney shaped nucleus, fights parasites. Involved in allergy, 3.basophils*: dark granules, bilobed nucleus, mediates allergy, histamine production, b) agranular leukocytes 1. monocytes*: in blood, immature. Large nucleus with a notch. Migrates to tissues. - In the tissues, it matures into macrophage. Phagocytic, non-specific. 2. lymphocytes: B & T cells. Specific immunity. Has “memory”. - large round nucleus. Very little cytoplasm visible. - cannot tell difference between T and B cell based on morphology - B cells  antibodies, has memory - T cells Kill virally infected cells, cancer cells. Recognizes foreign tissues, Has memory -Helper T cells: coordinates all arms of immunity (nonspecific cells, B cells & T cells). HIV kills helper T cells. The person becomes immunocompromised.

Figure 20.5 Histology of White Blood Cells RBC RBC RBC RBC RBC Neutrophil LM  1500 Eosinophil LM  1500 Basophil LM  1500 Monocyte LM  1500 Lymphocyte LM  1500 (see neutrophil in action) 17

Leukocytes

Figure 20.7 Structure of a Blood Clot Network of fibrin fibers Trapped RBCs in fibrin strands See video on clotting Platelets Blood clot SEM  4675 19