BSCI202 FINAL STUDY GUIDE Blood is the only fluid tissue in the human body and it is classified as a connective tissue Living cells are called formed elements Erythrocytes are red blood cells they transport oxygen and CO2 formed from erythroblasts Biconcave disk allows the cell to have a large surface area which is good for diffusion and gas exchange Essentially little bags of hemoglobin with flexible membranes which allow them to fold up and move through tiny capillaries while maintaining their shape They have no nucleus and contain very little organelles Because they have no mitochondria and use anaerobic glycolysis for energy they do not expend any of the O2 they are carrying which is optimal for O2 transport 5 6 billion RBCs are present per ml of blood They also maintain osmolarity and blood plasma pH each hemoglobin molecule has 4 heme groups that contain iron Fe Leukocytes are white blood cells they defend the body against pathogens Platelets are cell fragments they are formed from megakaryocytes and are important in blood clotting The non living matrix consists of plasma the fluid component of blood and solutes A blood hematocrit is created when blood is centrifuged Erythrocytes sink to the bottom of the test tube 45 of blood this is the hematocrit The buffy coat contains leukocytes and platelets less than 1 of blood it is a thin whitish layer between the erythrocytes and the plasma The plasma rises to the top 55 of blood Plasma constituents 7 Water is the solvent for carrying other substances also absorbs heat Salts electrolytes ions like Na K Ca2 Cl and HCO3 are responsible for maintaining osmotic balance pH buffering and regulation of the membrane s permeability Relatively high concentrations of Na and Cl Relatively low concentrations of H HCO3 K and Ca2 Plasma proteins increase osmotic pressure buffer H increase blood viscosity and provide fuel during starvation the three major types are listed below Albumin synthesized in liver deals with osmotic balance and pH buffering major component in kwashiorkor major contributors to plasma oncotic osmotic pressure and they also act as carrier proteins for molecules that don t dissolve in blood easily Fibrinogen synthesized in liver deal with blood clotting Globulins most synthesized in liver but some are synthesized by lymphocytes are responsible for defense via antibodies as well as lipid transport also carriers clotting factors precursor proteins like angiotensinogen and immunoglobulins Substances transported by the blood Nutrients like glucose fatty acids amino acids and vitamins Waste products of the metabolism like urea uric acid bilirubin and creatinine Respiratory gases dissolved like oxygen and CO2 Hormones The average blood volume for men is 5 5L and for women it is 5 0L Oxygen rich blood is scarlet red while oxygen poor blood is dull red Blood pH is ideally between 7 35 and 7 45 we use 7 4 as a baseline Blood temperature is slightly higher than the body s normal temperature at 38 degrees C or 100 4 degrees F and it is used to transfer heat throughout the body Ringer s Solution is a solution of distilled water which contains electrolytes and compounds so that they possess the same concentrations as they occur in bodily fluids This solution is iso osmotic to our blood and tissues because blood and tissue osmolarity must be equal to prevent new movement of fluids Ranges between 280 300 mOsm L we use 300 mOsm L as a baseline Osmosis is the cycle in which water or solvent diffuses down its concentration gradient Solutes in the body include Na K and Ca2 ions Changes in the electrolyte balance causes water to move from one compartment to another this alters blood volume and blood pressure and can impair the activity of cells Water moves from low solute to high solute high solvent to low solvent solute the substance being dissolved ions proteins solvent the substance that holds the solute water Pure water has zero solute present Water reabsorption follows solute reabsorption Acidosis is when blood becomes too acidic 7 35 Alkalosis is when blood becomes too basic 7 45 In each of these the respiratory system and kidneys work together to help restore blood pH to 7 4 CO2 can dissolve in water located in the blood plasma and form carbonic acid H2CO3 CO2 H20 H2CO3 H this is an acid HCO3 bicarbonate The acid base balance is essential to maintaining homeostasis Most ions originate as by products of cellular metabolism There are complications with acid base disturbance Conformational change in protein structure Changes in excitability of neurons Changes in the balance of other ions Cardiac arrhythmias Vasodilation vasoconstriction Acids are proton H donors Strong acids dissociate completely and liberate all of their H in water Weak acids like H2CO3 dissociate only partially Bases are proton H acceptors Strong bases dissociate easily in water and tie up H Weak bases like HCO3 and ammonia are slower to accept H BLOOD COMPOSITION REVIEW Plasma consists of Water Ions Organic molecules Amino acids Proteins albumins globulins and fibrinogen Glucose Lipids Nitrogenous wastes Trace elements and vitamins Gases CO2 and O2 Cellular elements Red blood cells White blood cells Lymphocytes Monocytes Neutrophils Eosinophils Basophils Platelets The fetal liver and spleen are the early sites of blood cell formation Bone marrow takes over hematopoiesis blood cell formation by the seventh month Fetal hemoglobin differs from the hemoglobin produced after birth it has a gamma subunit in place of a beta subunit and a higher affinity for oxygen Physiologic jaundice results when the liver can t rid the body of the breakdown products of hemoglobin fast enough Hemoglobin Hb binds strongly but reversibly to oxygen because of this 98 5 of oxygen is bound to Hb and only 1 5 is dissolved in the plasma Each Hb molecule has four oxygen binding sites4 Globin 4 heme groups 4 polypeptides and Heme is an iron containing group It can also bind to CO2 and H Formation of Erythrocytes 100 to 120 days Mature RBCs are not able to divide grow or synthesize proteins and they wear out in When they wear out RBCs are eliminated by phagocytes in the spleen or liver Lost cells are replaced by the division of hemocytoblasts in the red bone marrow Iron is a component of hemoglobin in men the normal Hb content of blood is 13 18 gram dL and in women the normal Hb content of blood is 12 16 gram dL The rate of erythrocyte production is controlled by the hormone erythropoietin EPO The
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