Blood Stem Cells RBC Life Cycle Anemia WBCs Marieb 17 Be able to identify the formed elements and where they are formed. Be able to describe the concepts of potency, lineage, and commitment specifically in relation to RBCs. Be able to describe the steps involved in the production of a RBC and name the cells associated with these steps. Be able to explain why red blood cells die and how they are recycled. What does EPO do? What is anemia? Marieb 17

RBC Formation Hematopoiesis-blood cell formation Red marrow Sinusoidal Capillaries 100-200bil/day

Blood Cell Lineage Hemocytoblast Potency Committed cells Lineage- family tree Potency- measure of how many different types of cells and arise form a particular cell Totipotent- can make all cells, even extra embryonic tissue Pleuripotent- can make all cells of the body Multipotent- can make all or most of the cells in a tissue type Unipotent- can make only a single type of cell Committed cells- point at which a particular cell is committed to its fate (usually used to discuss when a cell is multipotent) Cell fate- process of a cell committing to a particular pathway

Birth of a Red Blood Cell: Division Hematocytoblast Myeloid Stem Cell Proerythroblast Hematocytoblast = Hematopoietic stem cell (HSC) Proerythroblast is committed May only divide to make a proerythroblast and a early erthyroblast or make two proerythroblasts

Birth of a Red Blood Cell: Maturation 1 Early erthyroblast Late erthyroblast Normablast Early erthyroblast- basophilic. These cells are still able to divide and contain all the organelles found in a normal cell and A LOT of ribosomes Late erthyroblast- build up of iron and hemoglobin Normablast- ejection of the nucleus and mitochondria

Birth of a Red Blood Cell: Maturation 2 Reticulocyte erthyroblast Mature Red Blood Cell Reticulocytes immature RBCs. Still contain ribosomes for 2-3 days Represent about 2% RBCs in circulation

Death of a Red Blood Cell 100-120 day life span Macrophages Fe Recovered Bilirubin (yellow) As they age cells get stuck in areas with slow circulation Spleen recovers cellular components Liver recovers heme components Bilirubin is a by-product of porphyrin ring breakdown

Bilirubin Disposal Begins in the Liver Bile Urine Urocobilin Feces: Stercobilin Jaundice Stercoblin- bilrubin in bile altered in digestive process

Obstructive Jaundice Failure of bilirubin to enter the bile

Control of Red Blood Cell Production Erythropoietin (EPO) Kidney Trigger: low O2 Speeds Maturation of RBCs

Anemias Aplastic anemia Iron deficiency anemia Pernicious anemia Anemia= cell based failure in delivery O2 to tissue Aplastic anemia- failure in RBC formation Iron deficiency anemia- lack of Fe in Heme group Pernicious anemia- B12 important in the formation of RBCs B12 recovered from diet Intrinsic factor is needed to recover b12

Sickle Cell Anemia Single amino acid change 1 in 400 African-Americans 1 in 13 carriers

Leukocytes: White Blood Cells Normal Cells 4800-10800/μl Immune Function 11000+ Leukocytosis

Leukocytes are Important in Immune Function Granulocytes Agranulocytes Mnemonic Granulocytes: ”grainy” cells, tend to have a short life span and are produced as needed Agranulocytes: NOT ”grainy” cells, some can live for decades Basic=blue Acidic= red

Granulocytes: Neutrophils Neutral pH Lysozymes Hydrogen peroxide Kill Bacteria, fungi Phagocytes Show up during inflammation Pus!

Granulocytes: Eosinophils Eosin reveals acidic enviroments Kills worms Deal best with parasitic worms Often located near connective tissues

Granulocytes: Basophils “Base-loving” Histamine Inflammation Response Signals other cells Causes vasodilation

Agranulocytes: Monocytes Largest WBC Turn into macrophages Viruses Chronic Infections

Agranulocytes: Lymphocytes 25% of WBCs Blood supply Spleen, lymph nodes Many varieties Will discuss when we talk about immunity