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First Aid USMLE Step 1: Hematology & Oncology
Questions with Detailed Verified Answers (100% Correct
Answers) /Already Graded A+
Erythrocytes carry O2 to ____ and CO2 to ______
Ans: *Tissues, Lungs*
True or false, erythrocytes are biconcave and anucleate
Ans: True
What is the lifespan of an erythrocyte and what is its energy source?
Ans: Glucose (90% used in glycolysis, 10% used in HMP shunt).
Lifespan – 120 days
What does the Cl−/HCO3− anti porter allow RBCs to do?
Ans: Allows export of HCO3− and transport of CO2 from the periphery to
the lungs for elimination
What is a reticulocyte?
Ans: Immature RBC; reflects erythroid proliferation.
What is Erythrocytosis, anisocytosis and poikilocytosis?
Ans: Erythrocytosis = polycythemia = hematocrit.
Anisocytosis = varying sizes.
Poikilocytosis = varying shapes.
The small cytoplasmic fragment of a thrombocyte (platelet) is derived from
what? What is its lifespan?
Ans: Megakaryocytic, 8-10 days
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What other protein do platelets interact with to form the platelet plug after
endothelial cell injury?
Ans: Fibrinogen
What causes petechiae?
Ans: Thrombocytopenia or ↓platelet function
What do dense granules and alpha granules in platelets contain?
Ans: Dense granules: ADP, Ca2⁺
Alpha granules: vWF, fibrinogen, fibronectin
Approx. 1/3rd of platelets are stored where?
Ans: In the spleen
What is the fibrinogen receptor?
Ans: GpIIb/IIIa
What is the vWF receptor?
Ans: GpIb
What are my three granulocytes?
Ans: Neutrophil, eosinophil, basophil
List the WBC differential for ranges
Ans: Neutrophils (54-62%)
Lymphocytes (25-33%)
Monocytes (3-7%)
Eosinophils (1-3%)
Basophils (0-0.75%)
What do the specific granules in neutrophils contain?
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Ans: Specific granules contain ALP, collagenase, lysozyme, and lactoferrin
What do the azurophilic granules in neutrophils contain?
Ans: Azurophilic granules (lysosomes) contain proteinases, acid
phosphatase, myeloperoxidase, and β-glucuronidase.
In what deficiency do we see hypersegmented neutrophils?
Ans: Vitamin B12/ folate deficiency.
What are band cells?
Ans: Immature neutrophils- reflect states of myeloid proliferation (bacterial
infections, CML).
What are some neutrophil chemotactic agents?
Ans: C5a, IL-8, LTB4, kallikrein, platelet-activating factor.
What is a plasma cell cancer?
Ans: Multiple myeloma
For T cells, CD8 recognizes MHC _ while CD4 recognizes MHC _ ; also
what does CD28 do?
Ans: I, II,
CD28 (costimulatory signal) necessary for T-cell activation.
What are dendritic cells called in the skin? What type of MHC do they bear?
Ans: Langerhans cell in the skin; MHC II, and Fc receptors
Differentiates into Macrophages in tissues
Ans: What is a monocyte
Lipid A binds to what on macrophages to initate septic shock?
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Ans: Lipid A from bacterial LPS binds CD14 on
macrophages to initiate septic shock.
What cytokine can activate Macrophages?
Ans: γ-interferon
What are the causes of eosinophilia?
Ans: Neoplasia
Asthma
Allergic processes
Chronic adrenal insuficiency Parasites (invasive)
What are the two main products of the antihelminthic eosinophil?
Ans: Produces histaminase and major basic protein (MBP, a
helminthotoxin).
Basophilia is a sign of what?
Ans: Myeloproliferative disease, particularly CML
What are the 3 main products of basophils?
Ans: Heparin (anticoagulant) and
Histamine (vasodilator).
Leukotrienes synthesized on demand
Describe IgE mediated degranulation of a Mast cell
Ans: Mast cells can bind the Fc portion of IgE to membrane. IgE cross-
links upon antigen binding, causing degranulation, which releases
histamine, heparin, tryptase, eosinophil chemotactic factors.
What prevents mast cell degranulation?
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Ans: Cromolyn sodium prevents mast cell degranulation (used for asthma
prophylaxis).
What type of hypersensitivity reaction is implicated with Mast cells?
Ans: Involved in type I hypersensitivity reactions
Where Fetal erythropoiesis occurs in these ranges?
3-8wks
6wks-birth
10-28 wks
18-adult
Ans: Yolk sac: 3-8wks
Liver: 6wks-birth
Spleen: 10-28 wks
Bone marrow: 18-adult
What type of antibodies are found in A blood type plasma?
Ans: IgM anti B
What type of antibodies are found in B blood type plasma?
Ans: IgM anti A
What type of antibodies are found in AB blood type plasma?
Ans: None – universal donor of PLASMA; not blood because plasma has
no antibodies but RBCs have both A and B antigen, universal recipient of
RBCs
What type of antibodies are found in O blood type plasma?
Ans: A and B — Universal donor of RBCs, not plasma, because O blood
has no antigen on surface, universal recipient of plasma
What type of antibodies are found in Rh⁺ blood type plasma?
