Hematology Flashcards
(49 cards)
Erythrocyte life span?
120 days
Define erythrocytosis.
Polycythemia (increased hematocrit)
Define anisocytosis.
Varying erythrocyte sizes.
Define poikilocytosis.
Varying erythrocyte shapes
What is a reticulocyte?
Immature RBC; reflects erythroid proliferation
Thrombocyte life span?
8-10 days
What is contained in thrombocytes?
Dense granules (ADP and calcium) Alpha granules (vWF, fibrinogen, fibronectin)
What causes petechiae?
Thrombocytopenia or decreased platelet functino
What does vWF bind to?
Gp1b
What does the fibrinogen receptor bind to?
Gp2b3a
What are the two broad categories of leukocytes?
Granulocytes (neutrophils, eosinophils, basophils, mast cells) and mononuclear cells (monocytes, lymphocytes)
What is the normal WBC differential?
Neutrophils ~60% Lymphocytes ~30% Monocytes ~6% Eosinophils ~3% Basophils ~1%
What is contained within azurophilic granules (lysosomes) of neutrophils?
Proteinases, acid phosphatase, myeloperoxidase, beta-glucuronidase
When are hypersegmented neutrophils (6+ lobes) seen?
Vitamin B12/folate deficiency
What are band cells?
Immature neutrophils; when increased, they reflect states of increased myeloid proliferation (bacterial infections, CML)
List the 5 major neutrophil chemotactic agents.
C5a, IL-8, LTB4, kallikrein, platelet-activating factor
How do monocytes appear on blood smear?
Large, kidney-shaped nucleus
Extensive “frosted glass” cytoplasm
What activates macrophages?
IFN-gamma
What role do macrophages play in initiating septic shock?
Lipid A from bacterial LPS binds CD14 on macrophages to initiate septic shock
What is the role of eosinophils?
Defend against helminthic infection
Produces histaminase, major basic protein (MBP, a helminthotoxin), eosinophil peroxidase, eosinophil cationic protein, and eosinophil-derived neurotoxin
How do eosinophils appear on blood smear?
Bilobate nucleus
Packed with large eosinophilic granules of uniform size
What is the role of basophils?
Mediate allergic reaction
Granules contain heparin (anticoagulant) and histamine (vasodilator); leukotrienes synthesized and released on demand
How do basophils appear on blood smear?
Densely basophilic granules
What is the role of mast cells?
Mediate allergic reactions in local tissues
Bind the Fc portion of IgE to membrane; IgE cross-links upon Ag binding -> degranulation -> release of histamine, heparin, trypstase, and eosinophil chemotactic factors