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Human Anatomy and Physiology. Blood and hemodynamics. Blood composition. Plasma and formed elements Formed elements Erythrocytes, leukocytes, platelets. Blood composition. Hematocrit 45% polycythemia (circulation problem). Plasma. Contents - PowerPoint PPT Presentation
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Human Anatomy and Physiology
Blood and hemodynamics
Blood composition Plasma and formed elements Formed elements
Erythrocytes, leukocytes, platelets
Blood composition Hematocrit
<45% anemia (O2 delivery problems) >45% polycythemia (circulation problem)
Plasma Contents
90% water Protein (albumin acts as a buffer) Fats, amino acids, salts, gases, enzymes,
hormones Narrow osmolality range
Erythrocytes Manufactured by erythropoiesis
Committed cell: will form a specific cell type Erythroblasts undergo rapid mitosis Reticulocytes enter blood stream (2% of blood)
Erythropoiesis
Erythrocytes Function: gas exchange
Oxy- and deoxyhemoglobin
Erythrocytes Destruction (3 - 4 months) Trapped in spleen and destroyed by
macrophages Globin is recycled into amino acids Iron is used to make new RBC’s Rest of heme group converted to bilirubin Bilirubin appears in urine and feces
Erythrocyte disorders Athlete’s anemia ThalassemiaSickle-cell anemia
Blood doping among athletes
Leukocytes The only complete cells Protect against invasion Move out of blood by diapedesis
Move through tissues by amoeboid motionFollow chemical trails by chemotaxis
Leukocytes Types
Granulocytes: contain cytoplasmic granules Neutrophils, eosinophils basophils
Agranulocytes: without cytoplasmic granules Lymphocytes, monocytes
Abundance: Never Let Monkeys Eat Bananas
Neutrophils Characteristics
Multilobed (3 - 6 lobes) nucleus Twice the size of RBC’s Phagocytose bacteria
Eosinophils Characteristics
Bilobed nucleus Course granules stain deep red to crimson Twice the size of RBC’s Release digestive enzymes to kill worms (too large to
be phagocytosed)
Basophils Characteristics
Course, dark purple, black granules Twice the size of RBC’s Release histamine (inflammatory chemical), attract
other WBC’s to the area
Lymphocytes Characteristics
Large, dark purple nucleus About the size of RBC’s Act in immune response
Monocytes Characteristics
Large, dark purple nucleus Three times the size of RBC’s Leave blood stream acting to phagocytose viruses and
bacteria
Platelets Megakaryocytes (bone) rupture through
sinusoid capillaries Enucleate, age quickly (10 days)
Hemostasis
Hemostasis Phases
Vascular spasm Vasconstriction reduces blood flow
Platelet plug formation Platelets swell, and adhere to each other
Coagulation Blood transformed from liquid to a gel
Hemostasis Phases
Prothrombin activatorformed
Conversion into thrombin Fibrin seals the hole
RBCs and fibrin mesh
Blood typing RBC plasma membranes bear specific
glycoproteins recognized by the body Glycoproteins called agglutinogens ABO blood group (A, B, AB or O)
O (common), AB (least common)
Blood typing
Rh blood group Rh factor: 8 Rh agglutinogens C, D, E antigens most common Carrying Rh symbolized by +
Blood groups reported together (i.e., O+)
Rheology The study of blood flow Viscosity (i.e., polycythemia)
Rheology Flow rate = 1/viscosity
Rheology Flow rate is directly proportional to
differences in pressure F ∞ P1 - P2 or (∆P)
Rheology Flow rate is indirectly proportional to
vessel length (F = 1/L)
Rheology Flow rate is directly proportional to the
fourth power of the radius of the vessel F ∞ r4
Hemodynamics Rate of blood flow highest in smallest cross sectional
areas Functional significance
Totalarea
Velocity
Blood flow Laminar flow
Continuous (small vessels) Pulsatile (large vessels)
Blood flow Turbulent flow
Definition (obstruction, sharp turns, high flow rate)
Occurs after aortic and pulmonary valves or valves in veins
Compliance Tendency of blood vessel volume to
increase as pressure increases
C = ∆V/∆P
P1=160 mmHg, P2=120 mmHg, V1=5 l/min. V2=3 l/min.
C = 0.05 kPa-1
Are veins or arteries more compliant ?
Compliance
8X more blood
3X more elasticity
24X more compliant