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51 Cards in this Set
- Front
- Back
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What is the process called which forms erythrocytes?
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erythropoiesis
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How long does it take for erythropoiesis to occur?
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5-7 days
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Erythrocytes are released from the bone marrow in a mature form. True or False.
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False. Erythrocytes are released as reticulocytes.
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How long does it take for reticulocytes to mature into erythrocytes?
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24-48 hours.
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What is the physiologic function of erythrocytes?
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oxygen and carbon dioxide transport, via hemoglobin (Hb).
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In what forms is oxygen transported in the blood?
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1. dissolved in plasma (2%)
2. bound to Hb (98%) |
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What does SaO2 represent?
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(O2 combined with Hb) / (O2 carrying-capacity of Hb) x 100%
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What is the shape of the oxyhemoglobin curve?
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sigmoid
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What does P50 represent on the oxyhemoglobin curve?
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Partial pressure of 02 required to saturate 50% of Hb with O2. (=27mmHg, at normal body T, pH 7.4, and PCO2 of 40 mmHg)
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What does a "right shift" of the oxyhemoglobin curve signify?
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That Hb has a decreased affinity for O2, and O2 will preferentially dissociate to tissues.
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What factors can precipitate a right shift?
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1. increased H+ or decreased pH
2. increased PCO2 (Bohr shift) 3. increased temperature 4. increased 2,3 DPG |
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What is 2,3 DPG, and why might you see levels of it increase?
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Byproduct of anaerobic metabolism of glucose in the erythrocyte.
Levels increase with chronic hypoxia (eg. high altitude, chronic lung disease) |
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What factors can precipitate a left shift in the oxyhemoglobin curve?
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1. decreased H+ / increased pH
2. decreased PCO2 3. decreased temperature 4. decreased 2,3 DPG 5. Carbon monoxide |
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What does a left shift signify?
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O2 is bound more tightly to Hb and is less likely to diffuse to tissues.
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How does Carbon monoxide affect hemoglobin?
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1. CO has 240 x affinity for Hb vs. O2 (therefore is a competitive inhibitor of O2 binding).
2. CO shifts oxyhemoglobin curve to the left so that O2 that is bound cannot unload at tissues. |
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How does anemia affect hemoglobin?
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Anemia can be defined as a decrease in hemoglobin per unit of blood (or hematocrit). Anemia DOES NOT affect the O2 saturation of Hb.
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Which forms of hemoglobin are a) bright red, b) blue, and c)cherry red?
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a)oxygenated Hb
b)deoxygenated Hb c)carboxy Hb (CO bound to Hb) |
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Which chromosomes have the genes responsible for encoding the 2 different globulin forms required for a hemoglobin molecule?
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Chromosome 16 (alpha, zeta)
Chromosome 11 (beta, delta, epsilon, gamma) |
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What are the three forms of embryonic hemoglobin?
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1. Gower 1 (ζ2ε2)
2. Gower 2 (α2ε2) 3. Portland (ζ2γ2) |
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Which hemoglobin molecule is α2γ2?
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Fetal hemoglobin
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How long does fetal hemoglobin persist for?
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3 - 6 months
(will often see kids with hemoglobinopathies - sickle cell, thalassemia etc, presenting at this age due to inability to form their own functional adult Hb) |
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Why might you see elevations in fetal hemoglobin in an adult?
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- unable to produce proper beta chains required for adult hemoglobin
ie. sickle cell, b-thalassemia |
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Which hemoglobin is represented by α2δ2? Is this form present in normal adult circulation?
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Hb A2. Yes Hb A2 represents 1.5 - 3.5 % of Hb, while HbA is the dominant form (α2β2)
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Which terms can be used to describe a) decreased production of hemoglobin, and b) production of improperly formed hemoglobin?
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a) thalassemias
b) hemoglobinopathies |
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The majority of carbon dioxide transport in the blood is carried out by hemoglobin. True or False.
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False. CO2 is transported by three means:
1. physically dissolved (5%) 2. physically dissoved as HCO3- (90%) 3. combined with Hb (only 5%) |
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The CO2 dissociation curve is influenced by the state of oxygenation of Hb. True or False.
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True. This is called the HALDANE EFFECT.
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What is stated by the Haldane effect?
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Deoxy Hb has an increased carrying capacity (compared to oxy Hb)for both CO2 and H+.
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How can you summarize erythrocyte-mediated gas exchange at the tissues?
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- as CO2 leaves the tissue cells and enters the RBC it causes more O2 to dissociate from Hb (Bohr shift)
-therefore, more CO2 combines with the Hb and more HCO3- is produced |
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How can you summarize erythrocyte-mediated gas exhange at the lungs?
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-as O2 passes from the alveoli into the RBC, Hb becomes saturated with O2 and becomes a stronger acid (proton donor)
-the more acidic Hb releases more H+ that binds to more HCO3- to form H2CO3 (within RBC) -H2CO3 dissociates into CO2 and H20 -CO2 diffuses from RBC into alveoli |
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What is the lifespan of a RBC? What is the term for anything that decreases the lifespan?
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1. 120 days
2. hemolysis |
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What is granulopoiesis?
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The process of forming granulocytes (basophils, neutrophils, eosinophils).
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What is the duration of granulopoiesis?
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14-18 days.
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What percentage of leukocytes in the normal peripheral blood are represented by the following?
a) eosinophils b) basophils c) neutrophils d) lymphocytes e) monocytes |
a)1-4%
b)0-1% c)60-70% d)30-40% e)3-10% |
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Which blood cells are referred to as agranulocytes?
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lymphocytes and monocytes
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What is the half-life and lifespan of neutrophils?
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a)t1/2 = 7 hours in blood
b)lifespan = 1-4 days in CT |
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Neutrophils are inactive in the blood. True or False?
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True. PMN's become activated in tissues.
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How many lobes does the nucleus of a PMN normally contain?
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3-5
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In which condition might you find hyper-segmented PMN's?
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megaloblastic anemia (+ would also see macrocytic cells and ovalocytes)
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What is the role of PMN's?
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phagocytosis of bacteria and other small pathogens
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Are PMN's involved in the innate or adaptive immune response?
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Innate
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Eosinophils play a role in the killing of parasites and response to allergens. True or False?
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True.
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Basophils are involved in some inflammations and leukemias. True or False?
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True.
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In what conditions might you see a neutrophilic leukocytosis (increase in number of neutrophils in the blood)?
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-infections (esp. bacteria, but also virus, fungi, parasites)
-injury (eg. hip fracture, burn) -inflammatory disorders (RhA) -some drugs (eg. corticosteroids) -myelocytic leukemias (increased no. of immature PMN's) - |
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In what conditions might you see a basophilic leukocytosis?
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-viral infx
-urticaria (hives) -post-splenectomy -myxedema (skin and tissue disorder usually due to severe prolonged hypothyroidism) -ulcerative colitis -systemic mastocytosis (too many mast cells) -malignancy -myeloproliferative disorders (chronic myeloid leukemia, myelofibrosis, polycythemia rubra vera) -hemolysis |
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In what conditions might you see a eosinophilic leukocytosis?
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-allergic rhinitis
-hay fever -asthma -drug reaction -parasitic disease |
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Monocytes are to macrophages as basophils are to what?
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Mast cells
Monocytes and basophils are the blood forms of macrophages and mast cells respectively. |
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What is the role of lymphocytes?
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-Adaptive immune response
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What do platelets contain?
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-granules!
-may have non-functional organelles that broke off from megakaryocyte |
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What do platelet granules contain?
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1. Alpha granules:
proteins associated with adhesion and clotting, ie. fibronectin; fibrinogen; factor VIII; VWF; factor V; heparin antagonist; thrombospondin 2. Dense granules: -ADP/ATP -Ca2+ -5-HT |
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What are immature PMN's called? Do they normally appear in the blood?
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Band cells. NO!
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True or false. There are two distinct pools of Neutrophils in the bloodstream?
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True. There is the circulating pool which appears in the CBC, but also the marginating pool, which will not be included in the CBC.
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