Formed elements 45 living blood cells suspended in plasma Blood cells cell

Formed elements 45 living blood cells suspended in

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Formed elements (45%)– living blood "cells" suspended in plasma. Blood cells & cell fragments. Erythrocytes (red blood cells, or RBCs) Leukocytes (white blood cells, or WBCs) Platelets Spun tube of blood yields three layers Plasma on top (~55%) Erythrocytes on bottom (~45%) WBCs and platelets in Buffy coat (< 1%) Hematocrit - Percent of blood volume that is RBCs . 47% ± 5% for males; 42% ± 5% for females 66
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Hematology – the study of blood. Adults have 4-6 L of blood (~1.5 gallons) Circulatory System consists of the heart, blood vessels and blood Main Functions of Blood Transport - O 2 , CO 2 , nutrients, wastes, hormones, and stem cells Protection - inflammation, limit spread of infection, destroy microorganisms and cancer cells, neutralize toxins, and initiates clotting. Regulation - fluid balance, stabilizes pH of ECF, and temperature control. ------------------------------------------------------ Plasma and Plasma Proteins Contains proteins (7%) Albumin (58% of the plasma proteins) - Helps maintain osmotic pressure Globulins (38% of the plasma proteins) Immunity: antibodies and complement Transport: bind to molecules such as hormones Clotting Factors Fibrinogen (4% of the plasma proteins ) Converted to fibrin during clot formation Other substances (2%) Ions (electrolytes): sodium, potassium, calcium, chloride, bicarbonate Nutrients: glucose, carbohydrates, amino acids Waste products: lactic acid, urea, creatinine Respiratory gases: oxygen and carbon dioxide ------------------------------------------------------- FORMED ELEMENTS Only WBCs are complete cells RBCs have no nuclei or other organelles Platelets are cell fragments Most formed elements survive in bloodstream only few days Most blood cells originate in bone marrow and do not divide Properties of Blood Viscosity - resistance of a fluid to flow, “friction of fluid”. Whole blood 4.5 - 5.5 times as viscous as water. Plasma is 2.0 times as viscous as water. Osmolarity of blood - the total molarity of those dissolved particles that cannot pass through the blood vessel wall. If too high, blood absorbs too much water, increasing the blood pressure. If too low, too much water stays in tissue, blood pressure drops and edema occurs. -------------------- 1. Erythrocytes (RBCs/ Red Blood Cells) Disc-shaped cell with thick rim; lose nearly all organelles during development; lack mitochondria or DNA. 67
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Blood type determined by surface proteins. Main Function: GAS Transport! Each RBC has hemoglobin (Hb). Produces carbonic anhydrase (which breaks down CO 2 into carbonic acid) important for pH balance. One RBC contains 250 million Hb groups thus it can carry 1 billion molecules of O 2. Hemoglobin (Hb) Structure Each Hb molecule consists of: Heme groups - binds O 2 to Iron(Fe 2+ ) at its center Globins - four protein chains: two alpha and two beta chains; 5% CO 2 in blood is bound to globin. Hematocrit: Percentage of whole blood that is RBCs. Men 42- 52% cells; women 37- 48% cells. RBC counts: men 4.6-6.2 million/μL; women 4.2-5.4 million/μL. Hemoglobin concentration: men 13-18g/dL; women 12-16g/dL.
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  • Fall '09
  • MICHAELVINSKI

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