Dr. Shaikh Mujeeb Ahmed Assistant Professor AlMaarefa College 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. Correlate the changes in plasma proteins with the clinical conditions.

BLOOD Two parts 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

Blood Composition

FUNCTIONS Transport of Defense against infection Maintenance of Respiratory gases (O2 & CO2) Nutrients Metabolites Hormones Defense against infection Maintenance of Body temperature Acid-Base balance Fluid-Electrolyte balance

Plasma Constituents Example Electrolytes Na+, K+, Cl-, HCO3 - Proteins Albumin, Globulin, Amino acids Carbohydrates Glucose Lipids Cholesterol, fatty acids Minerals Ca2+, PO43- Enzymes Alkaline Phosphatase, amylase Metabolites Bilirubin, urea, uric acid, creatinine

Types of Plasma Proteins Average concentration Albumin 4.8 g/100ml Globulins 2.3 g/100ml Fibrinogen 0.3 g/100ml Total 7.4 g/100ml

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

Examples of plasma protein and their functions Lipoprotein Nutrients Alkaline Phosphatase, amylase Enzymes Angiotensin Hormone γ - Globulin Antibodies Fibrinogen, prothrombin Clotting factors Albumin, ceruloplasmin, transferrin Carriers Gelsolin, Gc protein 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 α 1, α 2, 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

Summary

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

Plasma Constituent Functions Water (makes up 90% of plasma) Transport medium, carries heat Electrolytes Membrane excitability; osmotic distribution of fluid between ECF and ICF; buffer pH changes Nutrients, wastes, gases, hormones Transported in blood; blood gas CO2 plays role in acid-base balance Plasma proteins In general, exert an osmotic effect important in distribution of ECF between vascular and interstitial compartments; buffer pH changes Albumins Transport many substances; contribute most to colloid osmotic pressure Alpha and beta globulins Transport many water-insoluble substances; clotting factors; inactive precursor molecules Gamma globulins Antibodies Fibrinogen Inactive precursor for the fibrin meshwork of a clot