Flashcards in Hem & Onc - Anatomy Deck (61):
Describe erythrocyte (based on the meaning of the word itself). What is the function of erythrocytes? What are their defining characteristics/properties, and how does this effect their function?
Eryth = red, cyte = cell; Carries O2 to tissues and CO2 to lungs; Anucleate and biconcave, with large surface area-to-volume ratio for RAPID GAS EXCHANGE
What is the life span of an erythrocyte?
What is the source of energy of an erythrocyte, how is this energy used, and in what percentages?
Source of energy: Glucose (90% used in glycolysis, 10 % used in HMP shunt)
What important transporter does the erythrocyte membrane contain, and what is its function?
Chloride-HCO3- antiporter: allows RBCs to sequester HCO3- and transport CO2 from the periphery to the lungs for elimination
Define the following terms: (1) Erythrocytosis (2) Anisocytosis (3) Poikilocytosis
(1) Polycythemia, Increased hematocrit (2) Varying sizes (3) Varying shapes
What is a reticulocyte, and of what is it a marker?
Immature erythrocyte; Erythroid proliferation
In what process are platelets (thrombocytes) involved? From where are they derived? What is their life span?
Primary hemostasis; Small cytoplasmic fragment derived from megakaryocytes; 8-10 days
What activates platelets? What happens upon activation?
Endothelial injury; Platelets aggregate with other platelets & interact with fibrin to form platelet plug
What kinds of granules do platelets have, and what key things does each kind of granule contain?
DENSE GRANULES (ADP, Calcium)
ALPHA GRANULES (vWF, fibrinogen)
What organ is known for storing platelets? How much of the platelet pool is stored there?
What physical exam finding results from thrombocytopenia or platelet dysfunction?
What is the vWF receptor on platelets? What is the Fibrinogen receptor on platelets?
What are the 2 major categories of leukocytes, and what cells fall under each category?
GRANULOCYTES (Neutrophil, eosinophil, basophil) & MONONUCLEAR CELLS (Monocytes, lymphocytes)
Describe leukocyte (based on the meaning of the word itself). For what are leukocytes responsible?
Leuk = white, cyte = cell; Responsible for defense against infections
How many leukocytes are normally found in the blood?
Give the WBC differential from highest to lowest (per USMLE).
Think: "Neutrophils Like Making Everything Better"
For what kind of response are neutrophils responsible? In what kind of infections are neutrophils increased? What is neutrophils' main characteristic/function?
Acute inflammatory response; Increased in bacterial infections; Phagocytic
What is the most significant morphological/histological characteristic for identifying neutrophils?
What kinds of granules do neutrophils contain? What is found in each of these kinds of granules?
SMALL, MORE NUMEROUS SPECIFIC GRANULES - contain alkaline phosphatase, collagenase, lysozyme, & lactoferrin
LARGER, LESS NUMEROUS AZUROPHILIC GRANULES (lysosomes) - contain proteinases, acid phosphatase, peroxidase, and Beta-glucoronidase
What is a neutrophil finding relevant to vitamin B12/folate deficiency?
Hypersegmented polys (5 or more lobes of nucleus)
What are band cells? In general, what do increased number of them reflect? Give 2 examples of conditions in which this is seen.
Immature neutrophils; Increased myeloid proliferation (bacterial infections, CML)
Describe monocyte (based on the meaning of the word itself). Where are they found? Into what do monocytes differentiate, and where?
Mono = one (nucleus), cyte = cell; In the blood; Differentiates into macrophages in tissues
What are the significant morphological/histological characteristics of monocytes?
Large, kidney shaped nucleus; Extensive "frosted glass" cytoplasm
Describe macrophage (based on the meaning of the word itself). From where do they differentiate? Where are macrophages found, and what is there life span like?
Macro = large, phage = eater; From circulating blood monocytes; Long life in tissues
What major role(s) do macrophages play?
(1) Phagocytose bacteria, cell debris, and senescent RBCs (2) Scavenge damaged cells & tissues (3) Can function as antigen-presenting cell (via MHC II)
What activates macrophages?
What is a key cell surface marker for macrophages?
Describe eosinophil (based on the meaning of the word itself). What are defining morphological/histological characteristics of the eosinophil?
Eosin = a (pink) dye, philic = loving; Bilobate nucleus; Packed with large eosinophlic granules of uniform size.
What major role(s) do eosinophils play?
(1) Defend against helminthic infections (using major basic protein) (2) Highly phagocytic for antigen-antibody complexes
What 3 products does eosinophil produce, and what effect(s) does each have?
(1) Major basic protein - defend against helminth infections (2) Histaminase (3) Arylsulfatase [(2) and (3) help limit reaction following mast cell degranulation]
What is the mnemonic for remembering the causes of eosinophila? What are they?
NAACP = Neoplastic, Asthma, Allergic processes, Collagen vascular diseases, Parasities (invasive) (Note: Firecracker has better mnemonic = CCHINA)
What is the defining morphological/histological characteristic of basophils?
Densely basophilic granules; Think: "BASophil = BASophilic = staining readily with BASic stains"
What major function do basophils have?
Mediate allergic reaction
What kinds of granules are found in basophils? What do they contain?
Densely basophilic granules contain: (1) Heparin (anticoagulant) (2) Histamine (vasodilator) (3) Leukotrienes
What general function do mast cells have, and where? More specifically, by what mechanism do mast cells function?
Mediates allergic reaction in local tissues; Can bind Fc portion of IgE to membrane, IgE cross-links upon antigen-binding, causing degranulation (of mast cell granules)
What major things are found in mast cell granules?
Histamine, Heparin, Eosinophil chemotactic factors
Which other immune cell do mast cells resemble, and how so?
Mast cells resemble basophils structurally and functionally but are not the same cell type
In what kinds of hypersensitivity reactions are mast cells involved?
What prevents mast cell degranulation, and in what settings is it used?
Cromolyn sodium; Asthma prophylaxis
What major roles do dendritic cells play?
(1) Highly phagocytic antigen-presenting cells (APCs) (2) Function as link between innate & adaptive immune system
What receptor(s) do dendritic cells express on their surface?
(1) MHC Class II (2) Fc receptor
What are dendritic cells called in the skin?
What are the divisions of lymphocytes?
Divided into B cells, T cells, and NK cells
What are the defining morphological/histological characteristics of lymphocytes?
Round, densely staining nucleus with small amount of pale cytoplasm
What are the overall roles of the different types of lymphocytes?
B cells and T cells mediate adaptive immunity. NK cells are part of the innate immune response.
What major role(s) do B lymphocytes play?
(1) Part of humoral immune response (2) Can function as an APC via MHC II
From where do B lymphocytes arise, and where do they mature? To where do they migrate?
Stem cells in bone marrow; Bone marrow (Think: B = Bone Marrow); Migrates to peripheral lymphoid tissue (follicles of lymph nodes, white pulp of spleen, unencapsulated lymphoid tissue)
What happens to B cells once they encounter antigens?
Differentiate into plasma cells that produce antibodies & memory cells
What is the function of plasma cells?
Produces large amounts of antibody specific to a particular antigen
What are the defining morphological/histological characteristics of plasma cells?
Eccentric (off-center) nucleus, clock-face chromatin distribution, abundant RER, & well-developed Chromatin apparatus
What is a classic example of plasma cell cancer?
What major role do T lymphocytes play?
Mediate cellular immune responses
From where do T lymphocytes originate, and where do they mature?
Stem cells in bone marrow; Thymus (Think: T = Thymus)
Into what types of cells can T lymphocytes differentiate?
(1) Cytotoxic T cells (2) Helper T cells (3) Regulatory T cells
What kinds of cell surface markers do cytotoxic and helper T cells express? What kind of MHC does each recognize?
Cytotoxic T cells: express CD8, recognize MHC I; Helper T cells: express CD4, recognize MHC II (Think: MHC x CD = 8)
What does CD stand for?
Cluster of differentiation
What is necessary for T cell activation?
CD28 (costimulatory signal)
What percentage of circulating lymphocytes are T cells?
What kind of (hematological) cell is an important component of granuloma formation? Give 2 examples of diseases/conditions associated with granuloma formation.
Macrophages; Important component of granuloma formation (e.g., TB, sarcoidosis)
In general, how common is isolated basophilia? For what kind of disease can it be a sign? Give a specific example of this kind of disease that is particularly associated with basophilia.
Isolated basophilia is uncommon but can be a sign of myeloproliferative disease, particularly CML