Blood Plasma and Plasma Proteins: Introduction and Characteristics PDF

INTRODUCTION CHARACTERISTICS OF THE BLOOD 1. Blood as a Connective Tissue a. Cells - RBC, WBC, Matrix - fluid, Fibers - fibrinogen 2. Color (depends on oxygenation) a. Arterial blood - Bright Scarlet red b. Venous Blood -Dark Crimson red 3. Viscosity (Thick, sticky liquid)...

INTRODUCTION CHARACTERISTICS OF THE BLOOD 1. Blood as a Connective Tissue a. Cells - RBC, WBC, Matrix - fluid, Fibers - fibrinogen 2. Color (depends on oxygenation) a. Arterial blood - Bright Scarlet red b. Venous Blood -Dark Crimson red 3. Viscosity (Thick, sticky liquid) a. 4.5 - 5.5 times the viscosity of water b. Flows 4.5 - 5.5 times slower than water 4. Specific Gravity a. 1.041 - 1.067 (average = 1.058) b. A little heavier than water 5. Characteristics a.Taste - salty b.Temperature- 37oC. c.PH - range 7.34 - 7.45 (Average 7.4) 6. Blood Volume a.7% of body weight c.Varies with Age, sex, muscularity, adiposity, activity, state of hydration, emotion etc  PRODUCTION AND DEGRADATION OF BLOOD CELLS various blood cells made in BM-hematopoiesis, includes erythropoiesis (RBCs) & myelopoiesis (WBCs and platelets) During childhood, almost every bone produces RBCs; as adults, production limited to larger bones: bodies of vertebrae, sternum, ribcage, pelvic bones, and bones of the upper arms and legs. In addition, during childhood, the thymus gland, is an important source of T lymphocytes The proteinaceous component of blood (including clotting proteins) is produced predominantly by the liver  Hormones by the endocrine glands and the watery fraction is regulated by the hypothalamus and maintained by the kidney Healthy erythrocytes have a plasma life of about 120 days before they are degraded by the spleen, and the Kupffer cells in the liver. Liver also clears some proteins, lipids, and amino acids, while kidney actively secretes waste products into urine HEMOPOIESIS : STAGES IN THE DEVELOPMENT OF BLOOD CELLS  FUNCTIONS 1. Transport of oxygen to tissues. 2. Transport of nutrients such as glucose, amino acids, and fatty acids 3. Removal of waste: carbon dioxide, urea, lactic acid 4. Immunological functions: circulation of white blood cells, and detection of foreign material by antibodies 5. Coagulation-response to a broken blood vessel, the conversion of blood from a liquid to a semi-solid gel 6. Transport of hormones 7. Regulation of body pH 8. Regulation of core body temperature PLASMA AND PLASMA PROTEINS By ADAOBI P. OKEKE  LEARNING OBJECTIVES By the end of this lecture, the student should be able to: List the components of blood plasma Differentiate between blood plasma and serum Identify the various plasma proteins State the origin of plasma proteins and list their properties Describe the functions of plasma and plasma proteins  INTRODUCTION Blood is composed of cellular elements which are suspended in blood plasma. A person who weighs 70kg will have approximately 5L of blood with about 2L being occupied by the cellular elements while the remaining 3L is plasma. Plasma is that part of the ECF which is contained within the vascular system. It appears as a straw-colored fluid and is composed mainly of water, but also carries proteins and small dissolved solutes.  Composition of Plasma PLASMA is a dilute solution, which contains 92% to 93% of water and 7% to 8% of solids (of which about 7% is protein) as well as gases. The solids are the organic and the inorganic substances. The table below shows the various components of blood plasma. Other important components include: clotting factors and lipoprotein particles  The normal plasma concentrations of some important electrolytes eg sodium, potassium, calcium and small molecules are almost similar to those in interstitial fluid because water and small solutes are freely exchanged across most capillaries. However, most capillaries are impermeable to plasma proteins. This results in a difference in protein concentration between the plasma and interstitial fluids such that an oncotic pressure gradient develops. This pressure opposes the filtration of plasma out of the capillaries. The table below shows the normal concentration of electrolytes and some other importance substances in the blood: Normal values of some important substances in plasma SUBSTANCE NORMAL RANGE GLUCOSE 100- 120 mg/dl CHOLESTEROL Up to 200mg/dl PLASMA 6.4- 8.3gm/dl PROTEINS CALCIUM 4.5- 5.5 mEq/L SODIUM 135- 145 mEq/L POTASIUM 3.5- 5.0 mEq/L MAGNESIUM 1.5- 2.9 mEq/L CHLORIDE 100- 110 mEq/L BICARBONATE 22-26 mEq/L SUBSTANCE NORMAL RANGE BILIRUBIN 0.5 to 1.5 mg/dL CREATININE 0.5 to 1.5 mg/dL IRON 50 to 150 μg/dL  SERUM Serum is the clear yellowish fluid that remains from blood plasma after clotting factors (such as fibrinogen and prothrombin) have been removed by clot formation. In other words, serum is a component of plasma while plasma contains serum with clotting factors (coagulants). Blood coagulates/clots when collected in a container and left to stand. The clot occurs due to the conversion of fibrinogen to fibrin. Blood cells are then trapped in this fibrin forming the blood clot. After about 45 minutes, serum oozes out of the blood clot. For purpose of clinical investigations, serum is separated from blood cells and clotting elements by centrifuging.  PLASMA PROTEINS The plasma proteins consist of albumin, globulin (alpha, beta & gamma), and fibrinogen fractions. They’re the most abundant substances in plasma. Other proteins found in the plasma include:, α1- Antiprotease, α-Fetoprotein (found in fetal blood),ceruloplasmin, Antithrombin-III, Steroid hormone-binding globulin, Thyroxine-binding Globulin, C-reactive protein, Haptoglobin, Hemopexin, Transferrin, Angiotensinogen, coagulation factors II, VII, IX, X etc Normal values of the plasma proteins are: Serum albumin : 4.5-5.0 g/dL Serum globulin : 1.0- 1.5 g/dL Fibrinogen : 0.2- 0.45g/dL  Origin of plasma proteins The B lymphocytes produce the gamma globulins, while most of the other proteins are synthesized in the reticuloendothelial cells of the liver. PROPERTIES OF PLASMA PROTEINS 1. MOLECULAR WEIGHT Albumin : 69,000 Globulin : 156,000 Fibrinogen : 400,000 Thus, the molecular weight of fibrinogen is greater than that of other two proteins. 2. SPECIFIC GRAVITY Specific gravity of the plasma proteins is 1.026.  Functions of plasma proteins 1. Role in Coagulation Of Blood 2. Role in Defense Mechanism of Body 3. Role in Transport Mechanism 4. Role in Maintenance of Osmotic Pressure In Blood 5. Role in Regulation of Acid-base Balance 6. Role in Viscosity of Blood 7. Role in Erythrocyte Sedimentation Rate 8. Role in Suspension Stability of Red Blood Cells 9. Role in Production of Trephone Substances 10. Role as Reserve Proteins 1. ROLE IN COAGULATION OF BLOOD Fibrinogen is essential for the coagulation of blood. 2. ROLE IN DEFENSE MECHANISM OF BODY Gamma globulins play an important role in the defense mechanism of the body by acting as antibodies (immune substances). These proteins are also called immunoglobulins. Antibodies react with antigens of various microorganisms, which cause diseases like diphtheria, typhoid, streptococcal infections, mumps, influenza, measles, hepatitis, rubella, polio myelitis, etc. 3. ROLE IN TRANSPORT MECHANISM Plasma proteins are essential for the transport of various substances in the blood. Albumin, alpha globulin and beta globulin are responsible for the transport of the hormones, enzymes, etc. The alpha and beta globulins play an important role in the transport of metals in the blood. 4. ROLE IN MAINTENANCE OF OSMOTIC PRESSURE IN BLOOD At the capillary level, most of the substances are exchanged between the blood and the tissues. However, because of their large size, the plasma proteins cannot pass through the capillary membrane easily and remain in the blood. In the blood, these proteins exert the colloidal osmotic (oncotic) pressure. Osmotic pressure exerted by the plasma proteins is about 25 mm Hg. Since the concentration of albumin is more than the other plasma proteins, it exerts maximum pressure. Globulin is the next and fibrinogen exerts least pressure 5. ROLE IN REGULATION OF ACID-BASE BALANCE Plasma proteins, particularly the albumin, play an important role in regulating the acid base balance in the blood. This is because of the virtue of their buffering action. Plasma proteins are responsible for 15% of the buffering capacity of blood. 6. ROLE IN VISCOSITY OF BLOOD Plasma proteins provide viscosity to the blood, which is important to maintain the blood pressure. Albumin provides maximum viscosity than the other plasma proteins. 7. ROLE IN ERYTHROCYTE SEDIMENTATION RATE Globulin and fibrinogen accelerate the tendency of rouleaux formation by the red blood cells. Rouleaux formation is responsible for ESR, which is an important diagnostic and prognostic tool. 8. ROLE AS RESERVE PROTEINS During fasting, inadequate food intake or inadequate protein intake, the plasma proteins are utilized by the body tissues as the last source of energy. Plasma proteins are split into amino acids by the tissue macrophages. Amino acids are taken back by blood and distributed throughout the body to form cellular protein molecules. Because of this, the plasma proteins are called the reserve proteins.  PLASMAPHERESIS This is a procedure in which the plasma is separated from the blood, discarded in total, and replaced with a substitution fluid such as albumin or with donated plasma from a healthy person. This also is generally performed to remove toxins or autoantibodies that have accumulated in the plasma. Plasmapheresis is used as a blood purification procedure for an effective temporary treatment of many autoimmune diseases. It is also called therapeutic plasma exchange. In an autoimmune disease, the immune system attacks the body’s own tissues through antibodies. The antibodies that are proteins in nature circulate in the bloodstream before attacking the target tissues. Plasmapheresis is used to remove these antibodies from the blood. USES Though plasmapheresis is used to remove antibodies from the blood, it cannot prevent the production of antibodies by the immune system of the body. So, it can provide only a temporary benefit of protecting the tissues from the antibodies. The patients must go for repeated sessions of this treatment. Plasmapheresis is an effective temporary treatment for the following diseases: 1. Myasthenia gravis – autoimmune disease causing muscle weakness 2. Thrombocytopenic purpura – bleeding disorder 3. Paraproteinemic peripheral neuropathy- dysfunction of peripheral nervous system due to an abnormal immunoglobulin called paraprotein.  4. Chronic demyelinating polyneuropathy – neurological disorder characterized by progressive weakness and impaired sensory function in the legs and arms due to the damage of myelin sheath in peripheral nerves. 5. GuillainBarré syndrome – autoimmune disease causing weakness, abnormal sensations (like tingling) in the limbs and paralysis. 6. LambertEaton myasthenic syndrome – autoimmune disorder of the  VARIATIONS IN PLASMA PROTEIN LEVEL Plasma protein levels vary independently of one another. However, in several conditions, the quantity of albumin and globulin change in opposite direction. An increase in all fractions of plasma proteins results in a condition known as hyperproteinemia and decrease in all fractions of plasma proteins is called hypoproteinemia. Variations in the level of plasma proteins are given in the table below: HYPERPROTEINEMI HYPOPROTEINEMIA A 1.Dehydration 1. Diarrhea 2. Hemolysis 2. Hemorrhage 3. Acute infections 3. Burns like acute hepatitis 4. Pregnancy and acute nephritis 5. Malnutrition 4. Respiratory 6. Prolonged distress syndrome starvation 5. Excess of 7. Cirrhosis of liver glucocorticoids 8. Chronic infections 6. Leukemia like chronic hepatitis 7. Rheumatoid or arthritis chronic nephritis THANK YOU FOR LISTENING