Blood Viscosity and Osmolarity  Blood is ~5x more viscous than water  Viscosity disorders o RBC or protein deficiency higher blood flow o Too many RBCs or protein  slower blood flow o Strain on heart, heart disease  Osmolarity (solute concentration in blood) o High osmolarity  high water absorption  high BP o Sodium, proteins Blood production  Blood loss o Bleeding o RBCs age and die o Plasma components used or excreted  Hemopoietic tissues (tissues that can produce various parts of the blood) o Liver o Spleen o Thymus  Active in adults o Bone marrow  Active in adults Erythrocytes (RBCs)  Pick up oxygen  unload to tissues     Pick up carbon dioxide  unload into lungs Lose nucleus and organelles o Anaerobic fermentation for energy o No aerobic resp. helps conserve oxygen for delivery Cytoplasm o Hemoglobin o Carbonic anhydrase Glycolipids on surface  blood typing RBCs and hemoglobin  Clinical significance - Amount of oxygen someone can carry o 1. Hematocrit test  % Of blood that is RBCs o 2. Hemoglobin concentration o 3. RBC count  Not the percentage  Values higher in men o Androgens (testosterone) stimulate RBC production o Periodic menstrual RBC loss o Inversely proportional to fat o Evolutionary adaptation  Breakdown begins in spleen fragments sent to liver RBC homeostasis o Negative feedback o Low count  hypoxemia o Kidneys detect hypoxemia they increase EPO output  EPO=erythropoietin o Takes a few days to reach normal RBC levels o Other causes of hypoxemia  1. Low atmospheric oxygen  2. Lethargy  active (exercise)  3. Emphysema  can’t be corrected Blood doping (more RBCs for more oxygen during physical activity)  Erythropoietin  Blood transfusion o Blood from higher altitudes RBC disorders – Polycythemia  Overproduction of RBCs  1. Cancer of bone marrow  2. Other causes o Dehydration o Smoking