Rq : Serum = plasma w/ fibrinogen and other other proteins involved in clotting removed.

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1 Functions of the blood Transport Nutritive Respiratory Excretory Hormone transport Temperature regulation Acid base balance ph ( ) Protective (immunology) Rq : It comprises both ECF (plasma) & ICF (inside blood cells) = 7% / 5L of total body mass Rq 2 : Three terms to design the blood volume Normovolema Hypovolema Hypervolema Composition of plasma (similar than ISF) >90% water (not pure water, electrolyte solution) Na+, Cl (approximate the composition of plasma through physiological saline, which corresponds to 0.9 g/dl of NaCl) Plasma contains small quantities of glucose, amino acids, lipids, O2, CO2 (added and rapidly removed ex O2 = distributed to various tissues) Plasma, by contrast with ISF, contains proteins (7g in every dl of plasma) = colloids a. albumins (most abundant, carriers for lipids,minerals, hormones) b. globulin help to regulate the functions of the circulatory c. fibrinogen (clotting) Rq : Serum = plasma w/ fibrinogen and other other proteins involved in clotting removed. How can we separate the plasma proteins? Different properties! Different precipitation by salt Sedimentation in ultracentrifuge (separated on the basis of their mol weight) Electrophoretic mobility (electric charges) Immunological characteristics Electrophoresis : principle Take a filter paper, drop of plasma on one hand, element positively charged on the other = migration of the proteins at different rate (influenced by MW, distribution of charges )

2 Rq : Proteins (negatively charged) = AA that contains either an acid radical or a basic radical. Rq : each pic represent a type of proteins, and the area under the pic represent the amount of proteins in these particular groups (Albumin > fibrinogen > globulins). Protein is lost in the urine due to kidney damage (smaller are lost primarly) = decreased of albumin rate Increase of gamma globulin = immunoglobulin

3 Origin of plasma proteins Most of them are produced in the liver (albumin, fibrinogen, alpha 1 & 2 & beta) The only fraction produced elsewhere = gamma globulin = lymphoid tissue (antibody) Roles of plasma proteins Intravascular osmotic effect. This is important in maintaining fluid and electrolyte balance. Contributes to the viscosity of the plasma Transport of insoluble substances around the body by allowing them to bind to protein molecules. Protein reserve for the body Clotting Inflammatory response Protection from infection the gamma globulins function as antibodies. Maintenance of the acid base balance. Blood plasma proteins like albumin functions as carrier proteins that help in the translocation of different biomolecules in body. Blood plasma contains the protease inhibitor enzymes like alpha 1 antitrypsin that help in the reduced proteolytic activity in the blood.

4 Osmotic effect maintaining the distribution of fluid between plasma & ISF by controlling transcapillary dynamics (capillary wall = freely permeable to H20 & ions) Only non diffusible solutes contribute to the O.P Diffusible DO not contribute because they become equally distributed in the two sides of the membrane Plasma proteins are non diffusible, that s why they can exert an osmotic pressure Colloidal osmotic (oncotic) pressure (C.O.P) 25 mm Hg (plasma side) There are 3 majors forms of fluid transport across the capillary wall : Diffusion C.O.P Bulk flow : Movement of water and solutes together due to a pressure gradient. Bulk flow differs from diffusion in that diffusion because diffusion is only affected by individual molecule, it does not require water. filtration = sort of bulk flow across porous membrane (sieve = passoire) pressure on one side greater than on the other side, move across through porous membrane or capillary wall, where larger molecules are going to be retain

5 Two important transport mechanisms for distribution of ECF. Filtration = push out the fluid from inside the capillaries Osmotic flow (due to plasma proteins) = retain fluid inside the capillaries = STARLING FORCES Opposing forces act to move fluid across the capillary wall Net hydrostatic pressure = blood (Pc) interstitial fluid pressure (Pif) favors filtration out of the capillary Oncotic pressure = blood ( Πc) interstitial C.O.P ( Πif) favors the absorption of ISF into the capillary N et filtration pressure (NF P ) = Net hydrostatic pressure oncotic pressure ou N F P = P c + Πif + P if + Πc Explications : The plasma within the capillary + ISF outside it = large quantities of low MW solutes (crystalloids, ex : Na+, Cl, K+) : easily penetrate capillary pores (concentrations identical in plasma and ISF) = no difference in water concentration. In contrast, the plasma proteins (colloids) are unable to move through capillary pores (non penetrating) = low concentration in ISF = lower water concentration in plasma = osmotic force that tends to cause the flow of water from the ISF into the capillary. Quantification of forces causing filtration at the arterial end of the capillary and absorption at the venous end. Outward forces are arbitrarily assigned positive values, so a positive net filtration pressure favors filtration, whereas a negative pressure indicates that net absorption of fluid will occur. Arrows in (b) denote magnitude of forces. No arrow is shown for interstitial fluid hydrostatic pressure (PIF) in (b) because it is approximately zero.

6 ++ : 1) Exchanges occurs along the whole length of the capillary, and magnitude and length of the arrows = net movement. 2) Only 90% of the fluid that leaves the capillaries at its arterial will re enter in the venous end. 10% is drained by the lymphatic vessels (not directly absorbed) and carry to be delivered to the bloodstream. Lymphatic system Plasma proteins & C.O.P Which proteins contribute the most to C.O.P? The osmotic pressure of a solution depends on the NUMBER of osmotically active particle/unit volume. Each protein fraction exerts an osmotic pressure which is a) directly related to its concentration in the plasma b) inversely related to the MW of that protein

7 EDEMA By the time the blood reached the arterials end = 55 instead of 35 and venous end = 25 instead of 15, imbalance between net filtration and net absorption Kwashiorkor = severe protein malnutrition : newborn baby, breast fed do obtain the proteins, but when the second baby arrives, & the first one no longer has the proteins = severe proteins malnutrition Elephantiasis : infection by a parasite, common one is a worm (filaria nematode), Capillary pores become wider, fluid out of the enter under the skin and find its way into the capillary into the ISF compartment lymphatic vessels + nest of parasites in the lymph nodes

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