Hematology Flashcards
(118 cards)
Erythrocyte
- carries O2 to tissues, CO2 to lungs
- anucleate & biconcave w/large surface area-to-volume ratio for rapid gas exchange
- 120 day lifespan, glucose is source of energy (90% glycolysis, 10% in HMP shunt)
- membrane has HCO3- antiporter, allows RBC to sequester HCO3- & transport CO2 from periphery to lungs for elimination
- polycthemia=inc. hematocrit
Anisocytosis
varying sizes
Poikilocytosis
varying shapes
Reticulocyte
immature erythrocyte, marker of erythroid proliferation
Thrombocyte
(Platelet), involved in primary hemostasis, small cytoplasmic fragment derived from megakaryocytes
- 8-10 day lifespan, when activated by endothelial injury, aggregates with other platelets & interacts w/fibrin to form platelet plug. Contains dense granules (ADP, Ca) and alpha granules (vWF, fibrinogen)
- approx. 1/3 of platelet pool stored in spleen
Thrombocytopeia results in?
(platelet dysfunction), petechiae
vWF receptor is?
GpIb
Fibrinogen receptor is?
GpIIb/IIIa
Leukocyte
- divided into granulocytes (neutrophil, eosinophil, basophil) & mononuclear cells (monocytes, lymphocytes)
- responsible for defense against infections
- normally 4,000-10,000cels/mm^3
Blood Cell Differentiation
-WBC differential from highest to lowers Neutrophils (54-62%) Lymphocytes (25-33%) Monocytes (3-7%) Eosinophils (1-3%) Basophils (0-0.75%)
Neutrophil
- acute inflammatory response cell, inc. in bacterial infections. Phagocytic. Multilobed nucleus. Small, more numerous specific granules contain alkaline phosphatase, collagenase, lysozyme, & lactoferrin
- larger, less numerous azurophilic granules (lysosomes) contain acid phosphatase, peroxidase, & B-glucuronidase
- Hypersegmented (5 or more) seen in vit. B12/folate deficiency
- inc. band cells reflect states of inc. myeloid proliferation (bacterial infection, CML)
Monocyte
- differentiates into macrophages in tissues
- large, kidney-shaped nulceus
- extensive “frosted glass” cytoplasm
Macrophage
- phagocytoses bacteria, cell debris, & senescent RBCs & scavenges damaged cells & tissues
- long life in tissues
- macrophages differentiate from circulating blood monocytes
- activated by gamma-interferon, can function as antigen-presenting cell via MHC II, CD14 is a cell surface marker for macrophages
Eosinophil
- defends against helminthic infections (major basic protein). Bilobate nucleus
- packed w/large eosinophilic granules of uniform size, highly phagocytic for antigen-antibody complexes
- produces histaminase & arylsulfatase (helps limit reaction following mast cell degranulation)
Causes of Eosinophilia
NAACP
Neoplastic, Asthma, Allergic process, Collagen vascular diseases, Parasites (invasive)
Basophil
-mediates allergic reaction, densely basophilic granules containing heparin (anticoag), histamine (vasodilator), & luekotrienes (LTD4)
Mast Cell
- mediates allergic rxn in local tissues, mast cells resemble basophils structurally & functionally but are not the same
- can bind the Fc portion of IgE to membrane
- IgE cross-links upon antigen binding, causing degranulation, which releases histamine, heparin, & eosinophil chemotactic factors
- involved in Type I Hypersensitivity rxns.
- Cromolyn sodium prevents mast cell degranulation (used for asthma prophylaxis)
Dendritic Cells
- highly phagocytic antigen-presenting cells (APCs)
- function as link b/w innate & adaptive immune system, express MHC class II & Fc receptor on surface
- called Langerhans cells in the skin
Lymphocyte
mediates adaptive immunity, divided into B cells & T cells, round, densely staining nucleus w/ small amount of pale cytoplasm
B lymphocyte
Part of humoral immune response, arises from stem cells in bone marrow. Migrates to peripheral lymphoid tissue (follicles of lymph nodes, white pulp of spleen, unencapsulated lymphoid tissue)
-when antigen is encountered, B cells differentiate into plasma cells that produce abs, & memory cells
-can function as an APC via MHC II
(Bone Marrow)
Plasma Cell
-produces large amounts of ab specific to a particular antigen. Off-center nucleus, clock face chromatin distribution, abundant RER, & well-developed Golgi apparatus
T lymphocyte
- mediates cellular immune response, originates from stem cells in bone marrow, but matures in the thymus
- T cells differentiate into cytotoxic T cells (express CD8, recognize MHC I), helper T cells (CD4, MHCII), & regulatory T cells
- CD28 (costimulatory signal) necessary for T-cell activiation, majority of circulating lymphocytes are T cells (80%)
Blood Group A
- A antigen on RBC surface & anti-ab in plasma
- incompatible blood transfusion can cause immunologic response, hemolysis, renal failure, shock, death
- anti A & B ab (IgM) do not cross placenta*
- anti Rh IgG do cross placenta*
Blood Group B
-B antigen on RBC surface & anti A ab in plasma