1. Introduction

• Connective Tissue
• matrix
• cells
• protein (fibers)

2. Functions of Blood

1. Transportation
2. Regulation of pH and electrolyte composition
3. Restriction of fluid losses
4. Defense against toxins and pathogens
5. Stabilization of body temperature

3. Composition of Blood

1. Plasma

• matrix of blood
• contains dissolved proteins

1. Formed Elements

• blood cells and cell fragments
• red blood cells (RBC’s)
• white blood cells (WBC’s)
• platelets

4. Plasma

1. Plasma proteins

1. Albumins

• 60% of the blood proteins
• transport of fatty acids and other substances

1. Globulins

• 35% of the blood proteins

1. Transport globulins

1. Thyroid-binding globulin => thyroxine
2. Metalloproteins => metal ions
3. Apolipoproteins => triglycerides, lipids
4. Steroid-binding proteins => Testosterone

1. Immunoglobulins (Antibodies)

• attack pathogens and foreign particles

1. Fibrinogen

• 4% of blood proteins
• blood clotting
• fibers

1. Other plasma proteins
1. Origins of the plasma proteins

1. Liver
2. Plasma cells
3. endocrine organs

5. Formed elements

1. Hemopoiesis

• process of making the formed elements of blood
• stem cells
• Progenitor cells

1. Erythropoiesis

• Formation of RBC’s
• Final maturation in blood (reticulocytes)
• Iron => Hemoglobin

• Controlled by erythropoietin (EPO)

Erythrocyte progenitor Cell

GF EPO

Reticulocyte

EPO

Erythrocyte

• Formation of leukocytes (WBC’s)
• Neutrophil, Basophil, Eosinophil & Monocyte
• regulation depend on growth factors (GF)

GF

Granulocyte/Monocyte progenitor

Granulocyte progenitor Monocyte progenitor

GF

GF

3. Thrombopoiesis

• Formation of platelets
• Fragmentation
• lifespan = 3 days
• control by two growth factors

Stem Cell

Megakaryocyte progenitor cell

GF

Megakaryocyte

Thrombopoietin (IL-6)

Thrombocyte

1. Red Blood Cells

• contain the pigment hemoglobin which binds and transports oxygen and carbon dioxide

1. Abundance of RBC’s

1. Structure of RBC’s

1. Shape => biconcave disc

• large surface area
• stackable (Rouleaux)
• flexible

1. Organelles

• lack mitochondria
• lack nuclei and ribosomes

1. Hemoglobin (Hb)

• 95% of intracellular protein
• about 280 million molecules of Hb in each RBC
• male 14-18 g/dl
• female 12-16 g/dl

1. Structure

• 2 alpha, 2 beta chains (quanternary structure)
• heme => one per polypeptide

1. Function

• low oxygen/high carbon dioxide => enhance Hb’s release of oxygen
• high oxygen/low carbon dioxide => enhance Hb’s binding of oxygen

1. Abnormal hemoglobin

• Thalessemia
• Sickle cell anemia

1. RBC lifespan and circulation

• round trip => 30 seconds
• lifespan => 120 days

• alpha and beta chains dissassembled
• heme units
• iron recycled (bound to transferrin)
• heme converted to billirubin

1. Blood types

• agglutinogen => antigens on surface of RBC’s
• agglutinins => antibodies
• A,B,AB and O
• Erythroblastosis fetalis

1. White Blood Cells

• granulocytes and agranulocytes

1. Characteristics of WBC circulation and movement

• do not circulate for extended periods of time
• ameboid movements & Diapedesis
• Positive chemotaxis
• Phagocytosis

1. General Functions

• non-specific defenses (neutrophil, basophil, eosinophil & monocyte)
• specific defenses (lymphocyte)

1. Neutrophils (50-75%)

• segmented nucleus
• highly mobile
• short life span
• digest bacteria
• release prostaglandins and leukotrienes

1. Eosinophils (2-4%)

• bilobed nucleus
• stain red
• phagocytic cells
• digest multicellular parasites
• increase during allergic reactions

1. Basophils (1%)

• injury
• release histamine and heparin

1. Monocytes (2-8%)

• large nucleus
• phagocytes

1. Lymphocytes (20-30%)

• Immune system
• T-cells, B-cells and NK cells

1. Platelets

• clotting
• flattened discs
• cell fragments
• continually replaced ( 9-12 day lifespan)
• removed in spleen

VI. Hemostasis

• hemostasis => process of stopping blood loss
• coagulation => convert fluid blood into a non-flowing gel
• Fibrin => protein filaments
• Thrombin => break fibrinogen into fibrin

Prothrombin XII_i

XII_a

fibrin mesh

• Extrinsic Pathway
• Intrinsic Pathway
• Vitamin K => Synthesis of fibrinogen and prothrombin
• vonWillebrand Factor => Platelet plug