Blood Physiology Lecture 1 PDF

Blood Blood Physiology Lecture 1 Human Anatomy & Physiology 1 - MED119 1 Lecture Objectives • Explain the composition and function of blood • Explain the composition and function of plasma • Explain the formation of plasma • Briefly describe the Plasma proteins 2 Blood • Liquid connective tissu...

Blood Blood Physiology Lecture 1 Human Anatomy & Physiology 1 - MED119 1 Lecture Objectives • Explain the composition and function of blood • Explain the composition and function of plasma • Explain the formation of plasma • Briefly describe the Plasma proteins 2 Blood • Liquid connective tissue that fills the heart & blood vessels • 8% of total body mass (man has 5-6 liters compared to 4-5 liters for woman) • The branch of science concerned with the study of blood, blood-forming tissues, & the disorders associated with them is Hematology. 3 Composition of Blood 1. Blood plasma: a watery liquid extracellular matrix that contains dissolved substances 2. Formed elements are cells & cell fragments. I. Red blood cells (RBC) II. White blood cells (WBC) A. Granular leukocytes i. Neutrophils ii. Eosinophils iii. basophils B. Agranular leukocytes A. T & B lymphocytes & natural killer (NK) cells B. Monocytes III. Platelets 4 5 Functions of Blood 1. Transport • Substances can be transported free in plasma, bound to plasma proteins, or within blood cells – gases, ions, vitamins, hormones, nutrients • Blood helps in excretion of waste materials by transporting them from different parts of the body to kidney • Blood also maintains body temperature, transporting heat – by doing so, it maintains the proper temperature in different organs & tissues, & in the body as a whole 6 Functions of Blood 2. Immunity • While the skin & mucous membranes physically restrict the entry of infectious agents, microbes constantly penetrate these barriers • WBCs are involved in the body’s battle against infection 3. Hemostasis • Bleeding is controlled by the process of hemostasis • Physical & cellular mechanisms participate in hemostasis • These mechanisms are complex, interrelated 7 Plasma • Fluid component of blood (a straw-colored) • 55% of the total blood volume is plasma • Blood cells & platelets are suspended in plasma. • Blood plasma is a mixture of proteins, enzymes, nutrients, wastes, hormones & gases. • If blood is allowed to clot, some plasma proteins are used up in the process of clotting – the fluid left behind after clotting is called serum 8 Plasma Constituents & Functions Constitute Description Function Water (91.5%) Liquid portion of blood Solvent & suspending medium. Absorbs, transports, & releases heat Plasma proteins (7%) Most produced by liver Responsible for colloid osmotic pressure, blood viscosity, transport hormones Other solutes (1.5%) Electrolytes Inorganic salts; Na+, K+, Ca2+, Mg2+; Cl-, HPO42-, SO42-, HCO3- Maintain osmotic pressure & essential roles in cell functions Nutrients Products of digestion Essential roles in cell functions, growth, & development Gases O2 CO2 N2 O2 is important in many cellular functions CO2 is involved in the regulation of blood pH N2 has no known function Regulatory substances Enzymes Hormones Vitamins Catalyze chemical reactions Regulate metabolism, growth, & development Cofactors for enzymatic reactions Waste products Urea, uric acid, creatine Most are breakdown products of protein metabolism that are carried to organs of excretion 9 Plasma Proteins • Plasma proteins (also serum proteins / blood proteins) are proteins found in blood plasma • Major solute constituents of plasma • Includes hundreds of enzymes, hormones, & hormone binding proteins • All the plasma proteins are synthesized in liver except the gamma globulins 10 TYPES OF PLASMA PROTEINS 1. Albumin (4.5-5 g/dl) 2. Globulin (2.0-3.0 g/dl) 3. Fibrinogen (0.2-0.45 g/dl) 11 Plasma Protein % of Total Origin Function Albumin (4.5-5 g/dl) 60% Liver Helps maintain COP, helps in transport of electrolytes, hormones, fatty acids, drugs, amino acids, dyes Globulin (2.0-3.0 g/dl) • α globulin 36% include forms: Liver Transport fat soluble vitamins • • glycoprotein, lipoprotein, Liver β globulin ϒ globulin Fibrinogen (0.2-0.45 g/dl) transferrin,ceruloplasmi n, immunoglobulin Lymphatic tissue 4% Liver ” Constitute a type of antibody Plays a key role in blood coagulation contributes to the viscosity of plasma 12 Functions of Plasma Proteins 1. Oncotic pressure – plasma proteins are osmotically active molecules – osmotic pressure of plasma due to plasma proteins is called oncotic pressure (normal 25 mmHg) – helps in maintaining volume of the vascular compartment – prevents loss of fluid from capillaries into interstitial tissue space 13 Functions of Plasma Proteins 2. Viscosity – plasma proteins contributes to about 50% of viscosity of blood 3. – depends upon the molecular shape of the plasma proteins – fibrinogen molecules that are elongated & fibrillar in shape contribute more to blood viscosity than albumin molecules that are ellipsoid in shape Immunity – antibodies are plasma proteins (gamma globulins) 14 Functions of Plasma Proteins 4. Coagulation – blood clotting depends on concentration of fibrinogen, prothrombin & other coagulation factors 5. Transport – plasma proteins severe as carrier molecule for transport of various substances like hormones, drugs 6. Buffering – plasma proteins form an important buffering system – helps in acid-base balance of the body 15 Functions of Plasma Proteins 7. Reservoir function – plasma proteins forms loose bound with the hormones, drugs, & metals to serve as a ‘reservoir’ 8. Synthetic function – provide substrate for the synthesis of protein hormones like erythropoietin 9. Determination of ESR – ESR mostly depends on the concentration of fibrinogen in the plasma 16 References • VanPutte, C. L., & Seeley, R. R. (2014). Seeley's anatomy & physiology. New York, NY: McGraw-Hill • Hall, J. E., & Guyton, A. C. (2011). Guyton and Hall textbook of medical physiology. Philadelphia, PA: Saunders Elsevier. • Sembulingam, K., PhD, & Sembulingam, P., PhD. (2012). Essentials of Medical Physiology (6th ed.). Jaypee Brothers Medical Pub. • Ganong’s Review of Medical Physiology 23e. (2021). McGraw-Hill. Any Questions? 18