Chapter 13 I Erythrocites a RBCs circulate for 120 days at which point the body wants new ones b No organelles c Functions i Transports Oxygen to tissues ii Removes carbon dioxide from tissues which is a toxic waste product iii Buffer blood pH 1 Stabilize neutralize pH 7 35 7 45 d Hemoglobin 4 globins 4 hemes i Oxygen carrying protein ii Comprises 90 of RBC dry weight iii Composed of 2 pairs of polypeptide chains called globins iv Each globin contains a heme molecule v Heme iron protoporphyrin 1 Orange iron e Production i Hematopoiesis 1 Development of mature myeloid cells RBCs WBCs platelets fragments of cells rom pluripotent stem cells ii Erythropoiesis 1 Development of mature erythrocytes only only RBCs a Stem cell to erythroblast to reticulocyte to erythrocyte b Reticulocytes will increase when erythrocytes are low to make more RBCs iii Stimulation 1 Decrease hemoglobin stimulates erythropoietin secretion from kidneys iv Regulation 1 Concentration of Hb in blood f Destruction i Hemolytic Anemia ii RBCs Hemelysis senescent RBCs Hemoglobin Hb Heme Bilirubin use to form bile the rest is thrown away iii Methemoglobin Oxidized iron 1 We don t want this in the body II Oxygen Transport a 1 Hb binds 4 atoms of oxygen i Oxyhemoglobin oxygen binds to heme ii When 1 globin binds to Oxygen the other oxygen s affinity increases b Average Hb 15g 100mL i 12 16 g cL range c Oxygen partial pressure i Pressure tension that oxygen creates when it is dissolved in blood ii Normal range 75 100mmHg iii 60mmHg hypoxcemia iv 35 45 mmHg III Carbon Dioxide Transport a Carbaminohemoglobin i Hemoglobin binds to CO2 b Most commonly transported as bicarbonate i Carbonic acid formed via carbonic anhydrase in RBC 1 H2CO3 very volatile through carbonic anhydrase will disassociate hydrogen acid to H and bicarbonate which is transported out in exchange for Cl ii 90 CO2 in arterial blood 60 CO2 in venous blood c Other forms i As dissolved gas ii Bound to Hb d CO2 partial pressure e Hb has a higher affinity for carbon monoxide than oxygen i Carbonmonoxide exhaust cars tires ii Poisoning drowsy sleepy coma death Moves very IV V quickly Acid Base Regulation by Lungs a Creation of bicarbonate and hyperventilate to breathe it out Erythrocyte Disorders a Polycythemia i Presents as flushed red with an increased clotting risk ii Excess erythrocytes iii Results in increased blood viscosity and volume iv Leeches b Anemia i RBC deficit ii Classification 1 Lower O2 carrying capacity leading to tissue hypoxia 1 Relative normal total RBC mass disturbances in plasma volume regulation a Pregnancy increased volume dilutional anemia b False anemia too much plasma for a normal iii Compensatory Mechanism amount of RBCs 1 Increased oxygenated blood flow increased heart rate cardiac output and preferential increase in flow to vital organs heart brain lung kidneys iv Mild Anemia Hb 8g dL 8 10 g dL 1 Usually no symptoms in healthy 2 Symptoms can appear in elderly with cardiovascular pulmonary disease more at risk for hypoxemia v Moderate Hb 8g dL 1 Low BP 2 Orthostatic nonorthstatic hypotension weakness 3 Vasoconstriction low O2 4 Tachypnea rapid breathing 5 Nocturnal Leg Cramps 6 Tinnitus ringing in ears c Aplastic Anemia i Reduced RBC synthesis 1 Stem Cell Disorder a Reduced hematopoietic tissue in the bone marrow replacement of normal bone marrow with fatty marrow 2 Pancytopenia reductions of RBCs WBCs and platelets ii Etiological Factors 1 Toxins 2 Radiation 3 Immunological Injury iii Clinical Manifestations Insidious onset 1 2 Palpitations transient murmurs tachycardia 3 Pancytopenia granulocytopenia iv Management 1 Avoid treat etiological factors 2 HLA ABO typing to identify blood donors 3 Maintain minimal hemoglobin and platelet levels 4 Prevent Manage infections 5 Determine efficacy of bone marrow transplant 6 7 Stimulate hematoiesis and bone marrow regeneration Immunosuppressants d Chronic Disease i Usually due to chronic renal failure 1 Impaired renal endocrine function results in reduced erythropoietin production 1 Low RBC hematocrit and Hb levels ii Diagnosis iii Treatment 1 Dialysis 2 Erythropoietin e Pernicious Anemia ii Reduced secretion of intrinsic factor prevents Vitamin B12 i Etiological Factors 1 Immunological 2 Atrophic Gastritis absorption iii Treatment 1 2 IV Vitamin B12 Intrinsic Factor f Megaloblastic Anemia i Etiological Factors 1 Folate deficiency 2 Vitamin B12 cobalamine deficiency ii Pathogenesis iii Diagnosis 1 Deficiencies in these coenzymes causes disruption in the DNA synthesis of blast cells in the bone marrow resulting in megaloblasts 1 Low RBC High MCV mean corpuscular volume and megaloblasts on peripheral blood smear 2 Low WBC and platelet counts iv Treatment 1 Diet 2 g Iron Deficiency IV Oral cobalamine folate i Most common nutritional deficiency in the world ii iii Diagnosis Insufficient Fe for Hb synthesis 1 Hypochromic microcytic RBC a Low MCV and low MCH MCHC mean corpuscular hemoglobin MCH concentration iv Treatment 1 Oral ferrous sulfate IV Ferric gluconate 2