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Plasma Protein. HMIM BLOCK 224. Dr. Shaikh Mujeeb Ahmed Assistant Professor AlMaarefa College. Objectives. Describe the composition of blood. Enumerate different plasma proteins. Explain the functions of plasma protein.
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Plasma Protein HMIM BLOCK 224 Dr. ShaikhMujeeb Ahmed Assistant Professor AlMaarefa College
Objectives • Describe the composition of blood. • Enumerate different plasma proteins. • Explain the functions of plasma protein. • Correlate the changes in plasma proteins with the clinical conditions.
BLOOD • Represents about 8% of total body weight • Average volume • 5 liters in women • 5.5 liters in men • Two parts • Plasma (55%) • Cells (45%)
BLOOD • Consists of 3 types of specialized cellular elements suspended in plasma (liquid portion of blood) • Erythrocytes • Red blood cells • Important in O2 transport • Leukocytes • White blood cells • Immune system’s mobile defense units • Platelets • Cell fragments • Important in hemostasis
FUNCTIONS • Transport of • Respiratory gases (O2 & CO2) • Nutrients • Metabolites • Hormones • Defense against infection • Maintenance of • Body temperature • Acid-Base balance • Fluid-Electrolyte balance
Properties of Plasma Proteins • Separated from plasma by ultracentrifugation • They are unable to pass across the capillary membrane consequently exerting an colloidal osmotic pressure of 25mmHg • Blood viscosity • Due to presence of polar residues like NH3+ and COO- - show electrophoretic mobility • Acts a Buffers
Functions of Plasma Proteins • Two general functions • Retaining fluid portion of blood in capillaries • Buffering body fluids • Specific functions of plasma proteins • Nutrients • Enzymes • Hormones • Antibodies • Clotting and fibrinolytic factors • Carrier molecules • Scavengers
Albumin • Synthesized in liver • 10-12 gms each day and half life is 20 days. • Exerts about 80-90% of the plasma colloid osmotic pressure. • It forms about 60% of total plasma protein. • Decrease in albumin – hypoalbuminaemia. • Fluid leaves the circulation- edema • Cause: malnutrition, liver disease, kidney disease • Function: transportation of Ca++, bilirubin
Globulins • Subdivided into α1, α2, β and γ • Alpha and beta globulins are synthesized in liver. • γ- gamma globulins are synthesized in reticuloendothelial system by plasma cells. • Alpha globulin transport lipoproteins, lipids, hormones(cortisol binding globulin, thyroid binding globulin and bilirubin. • Beta globulin transport lipids, cholesterol, iron and copper. • Gamma globulins (immunoglobulins) all the known antibodies are γ globulins.
Fibrinogen • As clotting factor • Provide viscosity to the blood
Plasma • Plasma proteins • Compose 6% to 8% of plasma’s total weight • 3 groups of plasma proteins • Albumins • Most abundant plasma proteins • Globulins • 3 subclasses • Alpha (α) • Beta (β) • Gamma (γ) • Fibrinogen • Key factor in blood clotting