- Erythrocytes account for 95% of entire formed element fraction and more than 40% of volume of whole blood- Complete Blood count (CBC): provides more detailed information about blood sample, including number of cells, morphology, and what’s inside them- Leukemia: production of large numbers of abnormal leukocytes (WBCs) in bone marrowo Interferes with other cells, preventing proper roles- Erythrocytes have biconcave shapeo Loss of biconcavity would reduce surface area for gas exchange, and negatively impact the physical properties of erythrocytes (flexibility, stack ability, etc.).- Erythrocytes are only anucleate cell in our body  non-mitotic  cannot synthesize proteins to repair themselveso 3-month lifespan- Erythropoiesis: 2 week processo Hematopoietic stem cell found in red bone marrow  can become RBC or WBCo Differentiates into myeloid stem cello Turns into proerythroblast  committed to becoming an RBCo Becomes basophilic erythroblast  contains ribosomes  begins producing proteins required for mature RBC like hemoglobino Becomes polychromatic erythroblast  ribosomes stain purpleo Becomes orthochromatic erythroblast  pink staining  demonstrates hemoglobino Finally, they turn into reticulocytes  have biconcave shape and eventually mature into RBCs- Erythropoietin (EPO): hormone released under conditions of hypoxia (low O2 in tissues)o Drives erythrocyte maturationo Blood Doping- Myoablation: A condition where blood cell production in the bone marrow is greatly impaired.- Mis-regulation of hormones like EPO or testosterone can lead to polycythemiao Polycythemia: abnormal increase in number of RBC- Missing precursors for erythropoiesis can delay cell cycle but not organelle growtho Results in megaloblasts  abnormally large erythrocytes Megaloblasts are prone to apoptosis, leading to overall decrease in number of RBC and inadequate O2- Anemia: Condition marked by a deficiency of RBCo Pernicious anemia: caused by vitamin B deficiencyo Iron deficiency anemia: caused when iron loss exceeds iron intake- Haldane effect: CO2 binding is favored by hemoglobin.- Bohr Effect: Binding of CO2 molecules to hemoglobin promotes oxygen release- Iron in hemoglobin has high chemical reactivity with organic molecules, which can lead to free radical generation and tissue damageo When RBC die, they are engulfed by macrophages and hemoglobin is carefully degraded into its components, each having a unique fate: - Fate of Heme:o Heme converted to biliverdin, then bilirubino Bilirubin transported to liver, incorporated in bileo In intestine, bilirubin is converted to stercobilin and incorporated in feces- Fate of Irono Iron is bound to transferrin, then transported to bone marrow for erythropoiesis- Hemolysis: premature rupturing of RBCs  uncontrolled and commonly occurs in response to immune reaction or infection- Never Let Monkeys Eat Bananaso Neutrophils (50-70%)o Lymphocytes (25-40%)o Monocytes (4-8%)o Eosinophils (2-4%)o Basophils (<1%)- Leukocytes are nucleated- Move by amoeboid motion  projections move forward, then posterior plays catchup- Can leave the blood and enter tissues (diapedesis)- Granulocyteso Neutrophils Large; polymorphonuclear Killers of bacteria using hydrolytic enzymes, defensins, and lysozymeo Eosinophils Large; bi-lobed nuclei; stain red Combat multicellular parasiteso Basophils Bi-lobed nuclei; stain blue Play supporting role at sites of infection; mediate inflammation- Agranulocyteso Lymphocytes Smallest leukocyte; single nucleus B lymphocytes: responsible for producing antibodies T-lymphocytes: defend against abnormal, cancerous, or virus-infected cellso Monocytes Largest leukocyte; U-shaped nucleus Exit circulation and transform into macrophages and perform phagocytosis Inflammatory and non-inflammatory macrophages- Donor compatibility rules for the ABO system are as follows:o Individuals with A blood type can donate to individuals with A or AB bloodo Individuals with B blood type can donate to individuals with B or AB bloodo Individuals with AB blood type can donate only to individuals with AB blood o Individuals with O blood type can donate to all other blood types Type O blood = universal donors.- Recipient compatibility rules for the ABO system are as follows:o Individuals with A blood type can receive blood from individuals with A or O bloodo Individuals with B blood type can receive blood from individuals with B or O bloodo Individuals with AB blood type can receive blood from individuals with A, B, or O blood, AB blood type are referred to as universal recipients.- Individuals with O blood type can only receive blood from donors with type O blood, - Hemolytic Disease: Occurs in newborns due to Rh compatibility between mother and fetuso Mother is Rh negative, and child is Rh positiveo During first pregnancy and child birth, fetal erythrocytes escape into mother’s circulationand sensitizes her immune system to produce anti-Rh+ antibodies Becomes problematic during second child birtho Treat is injection of anti-Rh factor antibodies, destroying any Rh+ cells in mother’s circulation- Hemostasis Process:o Vascular Spasm Phase Occurs immediately after vessel is damaged; smooth muscle in vessel constricts to limit blood flow; initiated by endothelin; leukocytes, platelets arrive and initiate clot formationo Platelet Phase Activation of platelets that arrive at site of damage and adhere to stick endothelium; chemical messengers activate more platelets, resulting in a platelet plug  temporarily stops blood loss; also promotes healing by releasing platelet derived growth factor, which stimulates cell divisiono Coagulation Phase Final phase; characterized by reinforcement of platelet plug by fibrin, an insoluble protein from soluble plasma protein fibrinogen; Fibrin entangles platelets, RBCs, and WBCs to dam off site of damage until repairedo Clot Retraction Not a phase really; platelets begin to contract in order to make clot more compact and pull edges of wound closer