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32 Cards in this Set
- Front
- Back
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Define: Hematopoiesis
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The formation and development of RBCs
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3 Stages of hematopoiesis in utero
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1. Prehepatic - AGM
2. Hepatosplenothymic - starts month 2 3. Medullolymphatic - in Bone Marrow (last trimester) |
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2 Types of Bone Marrow
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Red marrow - active hematopoietic reticular connective tissue (only marrow newborns have)
Yellow marrow - Adults have mostly yellow. They have red in bones of trunk and skill and proximal ephyses |
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Nutrient arteries penetrate the bone cortex via __________ and divide into smaller arteries.
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Nutrient arteries penetrate the bone cortex via NUTRIENT FORAMINA and divide into smaller arteries.
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Capillaries located within the marrow which supply hematopoietic connective tissue.
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Sinusoidal Arteries
New blood cells pass thought holes in the basal lamina and endothelial cells of the sinusoidal capillaries to enter the blood stream. |
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Adventitial reticular cells
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Fibroblast-like cells which make up the STROMA of the marrow.
**They are important regulators of the process of hematopoiesis. |
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Non-stromal cells
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The functional part of the marrow.
It's is composed of macrophages, mast cells, fat cells, plasma cells, and hematopoietic cells. |
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Erythropoiesis normall occurs in the:
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Reticular connective tissue cords of the bone marrow
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As RBCs differentiate, seveeral changes occur:
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- Cell/nucleus size decreases
- Ration of nucleus to cytoplasm decreases - chromatin in nucleus becomes more condensed - Cytoplasmic Hb content increases = more redish color - Decrease in the numbers of cytoplamsic ribosomes and RNAs result in less basophilic staining. - eventual loss of nucleus and more organelles |
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6 Defines Stages of Erythropoiesis:
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P-B-P-O-R-E
1. Proerythroblast 2. Basophilic Erythroblast 3. Polychromatophilic Erythroblast 4. Orthochromatophilic erythroblast 5. Reticulocyte 6. Erythrocyte (RBC) |
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How long is needed to produce an increased number of new, mature RBC in respons to an erythropoietic stimulus?
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1 week!
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What is the lifespan of an Erythrocyte?
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120 days
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What removed old RBCs from circulation?
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The Spleen!
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What leukocyte breaks down senescent RBCs and what is the process?
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Senescent RBCs are broken down by macrophages.
The Hb is broken down. The globins are converted to AAs. The Heme is converted to bilirubin. |
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RBCs lyse with age and release Hb into circulation. What removes it and how?
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The liver removed free Hb.
Hb binds to haptoglobin or is bound to heopexin and cleared by liver macrophages. |
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Carbonic Anhydrase -
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an enzyme that catalyzes the reaction of CO2 and H20 to Bicarbonate (HCO3-)
This is important for buffering the blood (Bohr Effect) |
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What is the normal lab count for RBCs?
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4-6 x 10^6 RBC/uL (4-6x10^12/L)
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What is HEMATOCRIT a measurement of?
What is the normal value? |
Hematocrit = % RBC volume in blood volume
Normal: 40-45% |
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Hemogloabin % is approximately __ of the hematocrit number.
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Hemogloabin % is approximately 1/3 of the hematocrit number.
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Mean Cell Volume =
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MCV = Hematocrit / RBC Count
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Mean cell hemoglobin =
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MCH = Avg. [Hb] / RBC
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Mean Cell Hemoglobin Concentration
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MCHC = Hemoglobin (g/L) / Hematocrit
Low values indicate decreased Hb synthesis (Microcytic anemia) |
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What is Anisocytosis?
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An abnormal variation in cell volume.
Microcytic/macrocytic |
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Define: Anemia
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Anemia = tissue hypoxia due to decreases hemoglobin concentarion freaquently a result of decreased RBC number, decreased Hb/RBC, or both.
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Anisocytosis:
Microcytic? Causes? |
Microcytic (<6 um)
Due to Iron deficiency |
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Anisocytosis:
Macrocytic? Causes? |
Macrocytic (>9 um)
Due to Folic acid or Vit. B12 deficiency |
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Irregularities in RBC shape:
2 types: |
Poikilocytpsis
2 types: Anisocytosis - many RBC with variable sizes Schistocytes - damaged RBC by flow through abnormal vessels. |
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Vit. B12 is absorbed by the body via:
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Intrinsic Factor
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Erythropoietin (EPO)
Made? Feedback loop? |
EPO
Made in Kidney (80%) and Liver (20%) Feedback loop: oygen sensing cells in the kidney respond to decreased O2 levels by increasing the production of EPO. |
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Cause of Pernicious Anemia?
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Vitamin B12 deficiency. Usually from lack of intrinsic factor.
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Folic Acid deficiency leads to:
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Mactocytosis
Usually the result of alcohol abuse |
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Granulopoiesis:
What are the 6 stages. |
Granulopoiesis
1. Myeloblast 2. Promyelocyte 3. Myelocyte 4. Metamyelocyte 5. Band/Stab form 6. Mature polymorphonuclear leukocyte |
