Term
| What are Red Blood Cells also called? How are they shaped and how is this adventitious? |
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Definition
*Erythrocytes
*Non-nucleated, spherical
*Shape increases surface area for gas exchange
*Thinness minimizes intracellular space for gases
*Size & flexibility improve motility |
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Term
| Where is hemoglobin? Where is it contained? What is its purpose? |
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Definition
*Iron-containing compound
*Contained in RBCs
*Binds with O2 |
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Term
Where are erythrocytes produced?
What is the formation of RBCs called?
What signals RBC production? Positive or Negative feedback loop? |
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Definition
*In the bone marrow
*Erythropoiesis
*Signals = O2 content of blood sensed in the kidney = release of erythropoetin by kidney; stimulates production of RBCs in marrow |
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Term
| Where are RBCs destroyed? What happens to them after they are destroyed? |
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Definition
*Destroyed in spleen after ~120days
*Components recycled = Heme converted to bilirubin = transported in blood to liver = conjugated and secreted in bile |
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Term
| What does excess destruction of RBCs cause? |
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Definition
*Build up of unconjugated bilirubin in blood
*Yellow discoloration to tissue = jaundice |
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Term
| What are normal RBC values? (In millions of cells per ml) |
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Definition
*Women ~ 4.2-5.5
*Men ~ 4.5-6 |
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Term
| What are normal Hemoglobin (Hgb) values? |
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Definition
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Term
| What are normal Hematocrit (Hct) values? |
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Definition
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Term
| What is having too many erythrocytes called? What er the two types of disorders? |
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Definition
*Polycythemia
*Primary (polycythemia vera) = absolute increase in # of RBCs = increased blood viscosity & imp. circulation = no cure
*Secondary = compensatory = high altitude or chronic hypoxemia |
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Term
| What is having too few erythrocytes called? What do all of these cause? |
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Definition
*Anemia
*Sx of hypoxia & compensetory processes = SOB, Fatigue, mild nausea, pallor of mucus memb, tachycardia |
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Term
| What are the three causes of anemia? |
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Definition
1. Lose too many = blood loss anemia (also serum loss - slow loss tolerated better than rapid)
2. Destroy too many = hemolytic anemia (Sickle cell anemia, thalassemia, G6PD deficiency)
3. Make too few = production deficient anemia (Dietary defic = Iron, B12, folate; Aplastic anemia (bone marrow), chronic or renal disease related) |
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Term
| How does anemia manifest on lab tests? |
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Definition
| *Abnormally low Hgb or RBC count |
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Term
| What are the universal s/s for anemia regardless of cause? How are anemia differentiated? |
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Definition
*Fatigue
*Pallor
*Tachycardia, DOE, CP
*Pica (eating non foods)
*Distinction = RBC size, morphology, ferritin levels serum B12 levels |
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Term
| What are the dietary causes of production deficient anemia? |
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Definition
| *Dietary deficiency = iron (Hgb), folate (DNA synth), B12 (pernicious anemia) - needed for DNA synth, usually due to impaired absorp. |
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Term
| What are the heritable causes of production deficient anemia? |
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Definition
*Bone marrow pathology (aplastic anemia) - often toxin induced
*Anemia of chronic disease - renal common |
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Term
| What is sickle cell anemia? |
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Definition
*Recessive inherited disorder
*More prevalent in African decent
*Structurally abnormal Hgb = abnormally shaped RBCs
*Cells may occlude capillaries = ischemia, severe pain, tissue destruction |
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Term
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Definition
*Inherited disorder c Mediterranean descent
*Abnormal & poorly fx Hgb
*Varies in severity |
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Term
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Definition
*Sex-linked recessive inherited disorder
*Defect in enzyme which causes excessive RBC destruction |
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Term
| What is synthetic erythropoetin called? Mechanism of action? Administration? Uses? |
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Definition
*Epogen & Procrit
*Stimulated RBC production
*Injection only
*Used for chemo assoc. anemias & primary bolood dyscrasias
*Increased risk of stroke, MI (black box) |
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Term
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Definition
*Blood clotting
*Complex process
*initiated by damage to vessel endothelium
*localized vasoconstriction formation of platelet plug, fibrin clot
*Normally controlled & self limiting |
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Term
| What are Blood platelets? What else are they called? Where are they created? Stored? What controls their release? |
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Definition
*Fragments of cells which have cell membrane, cytoplasmic granules, no nucleus
*Thrombocytes
*Created in bone marrow/stored in spleen
*Controlled by protein thrombopoitin - negative feedback loop |
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Term
| What types of chemical mediators are contained withing platelet granules? |
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Definition
*Chemicals to attract more platelets & stimulate platelet adhesion
*Coagulation factors (proteins)
*Fibrinogen (converts to fibrin)
*Plasminogen (limits clotting) |
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Term
| What do platelet membranes contain? |
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Definition
*Actin
*Myosin
*Receptor sites |
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Term
| What holds platelets in the "plug" together? Where do they connect? What are those sites called? |
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Definition
*Fibrin bridges between platelets
*Connect to platelets at receptor sites
*Glycoprotein IIb & IIIa |
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Term
| What does clotting require? What is required for manufacture of these? |
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Definition
*Protein factors
*Vitamin K |
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Term
| What are the 3 key points about the coagulation cascade? |
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Definition
1. Each step amplifies the next
2. End result is production of fibrin
3. Fibrin holds the clot together |
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Term
| What are the 3 basic steps of clot formation? |
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Definition
1. Brief vasoconstriction
2. Platelet adherence & aggrigation
3. Coagulation cascade creates fibrin |
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Term
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Definition
| Tissue plasminogen activator (t-PA)slowly reased from injured tissue = t-PA converts plasminogen to plasmin = slowly dissolves clot |
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