Hematology Unit 1 BL class of 2019 Flashcards
hematology is concerned with what in relation to blood?
nature, function, diseases
what are the 3 major types of cells in blood?
erythrocytes (RBC), leukocytes (WBC), platelets
peripheral blood is what?
blood flowing through arteries and veins
what is hematopoiesis?
the making of blood in marrow from hematopoietic stem cells, differentiation of development, production of all types of blood cells
cellular component of blood makes up _______-______% of its volume.
40-45%
what is the rest of blood (the liquid stuff) called?
plasma
what do you need to do to blood when drawing for tests?
know if plasma or serum is needed and what anticoagulant you need
list the components of plasma, buffy, and RBC layers of blood samples.
Plasma is in the plasma, buffy is WBC and platelets, then RBC
erythrocytes
bulk of cellular blood. lack nucleus, lack mitochondria. contain mucho mucho hemoglobin. 120 day life span. 175 billion made per day.
hemoglobin
tetrameric protein, reason RBCs are red. most has 2 alpha globulin chains and 2 beta globulin chains—>Hemoglobin A. each of the tetramers are bound to a heme prosthetic group
mutations in hemoglobin can lead to:
molecules that bind O2 less well, unstable molecules (premature breakdown—hemolysis), polymerization into long chains/crystals, abnormally shaped/fragile cells
hemoglobin S
most common mutation in RBC, leads to sickle cell disease. glu—>val at 6th position in beta globin chain
imbalances in alpha or beta globin chains lead to ______.
thalassemias
what is porphyria?
mutations in enzymes involved in synthesis of heme prosthetic group
what type of metabolism do RBCs depend on?
anerobic
mutations in genes coding for enzymes needed for anaerobic metabolism cause _______.
hemolytic anemia. most common version is G6PD (x linked, 15% of african male population). G6PD is most common human enzyme defect.
why are RBC’s shaped like a biconcave disc?
provides 40% more surface area than sphere with same volume, allowing for more gas exchange. allows them also to squeeze into different shapes due to ratio. allows them to move through/be culled in endothelium of the spleen
what allows the RBC to be deformable and still maintain its structural integrity?
a 2D elastic network of cytoskeletal proteins tethered to cytoplasmic domains on the transmembrane proteins in the membrane.
what substrates does bone marrow need to make RBCs?
iron (can be decreased due to diet, blood loss, etc.), vit. B12 and folic acid, erythropoietin
what are the 5 WBCs:
lymphocytes, neutrophils (PMNs), monocytes, eosinophils, basophils
lymphocytes
key players in adaptive immune response (development of memory after exposure to an infectious agent)
innate immunity
protection against infection that relies on pre-existing mechanisms. capable of rapid response
neutrophils
WBC responsible for finding, ingesting (phagocytosis), digesting bacteria, cell debris, dead tissue. 7 hours half life in peripheral circulation. 70 billion made per day.
malignancies arise from cells of _______ origin.
hematopoietic. all are clonal, neoplastic (cells have undergone several mutations altering proliferative/differentiation capacity). some are classic mutations (translocations, etc.) others have no characteristic cytogenetic abnormalities
lukemia
malignant cells from bone marrow are in the bloodstream
lymphomas
extramedullary collections of malignant lymphoid cells (involving lymph nodes or organs)
what are the two classifications of lukemia?
acute or chronic. acute=cells are immature, progression is rapid. chronic=cells are more mature, more indolent course
hemostasis
arresting of bleeding, allows blood to clot in response to damaged vessels. due to platelets. results from complex interactions btw platelets, endothelial lining of bv, and coagulation factors in response to endothelial disruption
how many platelets can a megakaryocyte produce?
5000
complete blood count began as what?
a measurement of Hg and cellular components of peripheral blood.
hemoglobin is measured where?
in vitro-RBC is lysed and Hg is converted to a spectrometer friendly form. most techniques use cyanmethhemoglobin (absorbance=525/540nm). shows a linear relationship btw light absorption and concentration of a sample
hematocrit is a measure of what?
how much of a sample is occupied by RBCs. is a %. done with formula: %=RBCxMCV
physiologic variables affect one’s RBC’s include what 3 things?
age, sex, altitude
aperture impedance
Coulter principle. Counts RBC, WBC, platelets. an electrical current is run across an aperture of known size—>cell or particle passes through—>current flow changes—>voltage surges—>surge size tells you what size it is. number of pulses tells you how many cells/particles. measures size of nucleus and cytoplasmic granularity
what are the x and y axes of an aperture impedance histogram?
x=range of pulse magnitudes, y=number of events
what can cause inaccuracy in aperture impedence
multiple cells enter at once
light scattering techniques
collect forward, narrow/wide angle scattered light. estimates size of a cell based on the scatter (measures cross sectional diameter).
erythrocyte indices
calculations for size, content, Hgb concentration of red cells. can help characterize anemias. Healthy=little variation.
Mean Corpuscular Volume (MCV)
average volume of red cells. derived from height of voltage pulse, calculated with Hct=MCVx RBC (RBC and HCT are determined manually—> HCTx10/RBC)
mean corpuscular hemoglobin
MCH is weight of Hgb of average red cell. calculated from MCH=Hgb/RBC
mean corpuscular hemoglobin concentration (MCHC)
average concentration of Hgb in a volume of packed red cells. MCHC=(Hgb/Hct)x100
Red cell distribution width (RDW)
measure of variation in size of red cells and is proportional to the width of the measured histogram
reticulocytes
immature, anucleate RBC that still have RNA, ribosomes, organelles (enable continued Hg production). Bone marrow 3-4 days—>released to peripheral blood 1-2 days—> lose RNA and organelles—>mature RBC
what stains RNA, ribosomes, organelles in the reticulum?
Supravital staining (brillant cresyl blue, methylene blue)
nucleated RBCs
nucleated RBCs/100 WBCs
what is thrombocytopenia?
too few platelets
what is thrombocytosis?
too many platelets
what is thrombocythemia?
neoplastic expansion of platelets
optical platelet counting
high angle and low angle scatter signals are combined fore each cell. transformed into volume plotted on vertical axis/refractive index values on horizontal to give a platelet scattergram
combination of impedance and optical counting
impedance channels are used as defaults, but a fluorescent channel is backup when there is an abnormality.
platelet measurements are made how?
forward scatter for size, side scatter for internal structure, fluorescence for RNA/DNA stain
labeled-platelet counts
counted by measuring green fluorescence form FITC on monoclonal antibody in a reagent. Binds the CD61 antigen found on all normal platelets. useful when there’s lots of RBC/WBC fragments
when do white cell counts and differentials stop varying/changing?
after puberty
what is a sheath flow-based counting system?
enable passage of single cells through a sensing zone where multi-parameter analysis can happen when several sensors info is combined
flow cytometry and light scatter for WBC counts
determined with flow cytometry+semiconductor laser. cell info is obtained with forward light scatter for volume, lateral for internal structure, fluorescent light for RNA/DNA info. produces scattergram
cytochemistry and light scatter
peroxidase channel uses cytochemical rxn to produce black rxn. product. neutrophils, eosinophils, monocytes, lymphocytes fall into 4 clusters (separated by electronic thresholds)
what is a blood smear made from?
EDTA anti coagulated blood to prevent artifact. observe at low then high power.
what is red cell morphology on a smear?
little size/shape variation, well spread,
White cell morphology on a smear?
concentrated at the end of the film
neutrophils morphology
acidophilic with fine granules, clumped chromatin in nucleus divided into 5 lobes. too few lobes-neutropenia. too many lobes-neutrophilic.
lymphocyte morphology
scant cytoplasm, round nucleus, dense chromatin. most abundant WBC from age 2-8. too few=lymphopenia, too many=lymphocytosis
monocyte morphology
largest cells, irregular lobulated nucleus, ample grey-blue cytoplasm, azurophilic granules, outline of cytoplasm is irregular, vacuoles. too few=monocytopenia, too many=monocytosis
eosinophil morphology
larger than neutrophils, bi-lobed nucleus, larger spherical granules, count is constant in life. too many=eosinophelia
basophil morphology
similar in size to neutrophils, nucleus obscured by purple-black-coarse granules, least abundant. too many=basophilia
anemia
insufficient RBC mass to deliver oxygen to peripheral tissues. defined by measuring hemoglobin concentration (Hgb), hematocrit (Hct), RBC
_______ have lower Hgb and Hct values than men due in part to more tenuous iron stores.
menstruating women
what lab measurements are used to define anemia?
Hgb, Hct, RBC count, MCV, MCHC, rDW, WBC count, differentia of various types of WBC (%)
what stain is used to observe red cell morphology changes?
Wright’s stain
reticulocytes can be identified by presence of _______ in cell for 1st day in circulation.
mRNA. only peripheral cell where you can routinely evaluate production by quantitating # of young cells in circulation. counted as % of 1000 red cells counted.
what is the normal % of reticulocytes in the blood?
.4-1.7%. increased is when it’s 3.5-5 fold greater than this.
reticulocyte index is useful for correcting reticulocyte counts fro red cell concentration and _________.
stress reticulocytosis. normal RI should be between 1 and 2 for a healthy individual.
what are the stress factors for a reticulocyte count?
1.5 (mild anemia>9gm/dl); 2.0 (6.5-9); 2.5 (severe
what does and RI >2 with anemia indicate?
loss of RBC leading to increased compensatory production of reticulocytes to replace lost RBC.
in anemias that develop over weeks, ________ w/in cells increases to make oxygen dissociation more efficient to compensate for low oxygen carrying capacity.
2,3-DPG. however, if it develops acutely, there is not enough time to make this compensatory mechanism
what are some symptoms of anemia?
shortness of breath, fatigue, rapid heart rate, dizziness, claudication, pain with exercise, pallor
Know his freaking scheme for anemia
seriously, he’s only shown it to you a million times.
is anemia associated with other hematologic abnormalities? YES (means what?)
bone marrow examination to look for: leukemia, aplastic anemia, myelodysplasia, myelofibrosis, myelophthisis, megaloblasitc anemia
is anemia associated with other hematologic abnormalities? NO (means what?)
ask next, is there an appropriate reticulocyte response to anemia?
is there an appropriate reticulocyte response to anemia? YES (means what?)
is there evidence of hemolysis? (yes or no) increased bilirubin/lactic dehydrogenase, decreased haptoglobin, hemosiderin in urine
is there an appropriate reticulocyte response to anemia? NO (means what?)
ask: what are the RBC indices?
is there evidence of hemolysis? YES (means what?)
evaluate for cause of hemolysis
is there evidence of hemolysis? NO (means what?)
evaluate for hemorrhagic causes of anemia
MCV>100
evaluate for macrocytic anemia
MCV 80-100
evaluate for normocytic anemia
MCV <80
evaluate for microcytic anemia
basic concepts of biochemistry/distribution of iron that are important for iron deficiency anemia
- iron exists in 2 valence states, ferric and ferrous. activity depends on state.; 2. in aqueous solutions Fe forms insoluble hydroxides unless bound to a protein/compound; 3. Fe salts are more soluble than low pH; 4. Fe balance in body is controlled by absorption, there are no active mechanisms for excretion; 5. losses of Fe each day are small (skin/mucosal exfoliation, urine, menstruation)
where is the majority of iron contained?
hemoglobin (65%). 6% is in myogolobin, 25% is in ferritin and hemosiderin (storage forms of iron). v. small amount is bound to transferrin. remainder (
iron absorption
goes from stomach (pH and gastroferritin optimize solubility)—>duodenum—>brush border of mucosal cell is where dietary non-heme enters—>converted to ferrous iron by DCYTB—> enters cell through divalent transporter—>stored/transported across bask-lateral membrane
what increases intraluminal absorption of iron?
presence of protein, vitamin C (for valence state)
what decreases absorption of iron?
phytates, oxalates, other food constituents cause it to precipitate and be less biologically available
iron cycle
iron is bound to transferrin—>goes to marrow and maturing normoblasts—>transferrin receptors on cells are bound—>normoblast incorporates it into hemoglobin
transferrin
84kDa plasma protein made in liver. binds iron in ferric form
what happens to iron in dead RBCs?
macrophages turn cells over in spleen, and sequester iron in ferritin stores.
what is the ferritin molecule structure?
coat made of 24 alternating H and L chains. center has ferric salts and 4500 atoms of iron can be held in 1 ferritin
hepcidin
25 aa peptide mad in liver in response to high iron intake, inflammation, infection.
what happens when hepcidin is increased?
plasma flow from stores goes down, iron saturation and plasma iron decrease, erythropoiesis goes down
what happens when hepcidin is decreased?
binds to ferroportin, degrades it. iron export out of cell goes down, iron accumulates in ferritin
transferrin receptor provides ______ for the iron cycle
direction. transferrin enters cell through clathrin coated pit to make endosomes. become acidified, iron exits endosome through DMT1 to go to storage sites. Transferrin returns to surface
what are the general characteristics of iron deficiency?
decreased Hg, decreased cell proliferation, mild hemolytic component (cell rigidity), mildly defective muscle performance, neurophysiological disfunction, nail ridges, upper gastric involvement, immune dysfunction
how does iron deficiency develop?
excessive losses, failure to accumulate iron, on-going losses/inability to gain iron during growth
steps of iron depletion:
- iron ferritin levels diminish; 2. iron deficient erythropoiesis; 3. overt anemia
how do you diagnose anemia?
start with a history, and look a the various symptoms, look at lab tests
differential diagnosis of anemia
anemia of chronic inflammation/infection, anemia of chronic disease, thalassemia, sideroblastic anemias
how do you replace iron?
iron salts orally, intramuscular/iv route when absorption altered/compliance is an issue. slowly normalizes, serum iron responds quickly, normal RBCs in 3-5 days.
do you stop iron treatment once Hg has reached normal levels?
NO! you need to replenish ferritin stores, so continue for a while after (deficient cells survive 3 months, so need to support)
what is iron overload?
increase in body burden of iron beyond the norm. can be caused by increased intake in diet, mutation in HLApH gene, repeated transfusions for anemia.
what are the organs damaged by iron overload?
heart, liver, endocrine organs
how do you treat iron overload?
therapeutic phlebotomy, chelation (Desferal)
each red blood cell contains ______ molecules of Hg.
280 million
what is the predominant form of hemoglobin in adults?
A (alpha 2, beta 2)
absence of what chain is incompatible with life?
lack of alpha globin chains
describe the numbers of amino acids in alpha and beta chains.
141 aa for alpha, 146 aa in beta globin
where does heme link to a histadine?
on the 87 on alpha, and the 92 on gamma, beta, s chain
how is the delivery of oxygen to tissues accomplished by Hg?
through allosteric regulation. (configuration changes allow different binding affinities)
what is a way to quantify the difference in oxygen affinity?
by P50. partial pressure of oxygen where oxygen protein is 50% saturated. P50 for Hg is 27mmHg, myoglobin is 2.75 mmHg
basic shape of the O2 dissociation curve mnemonic (pp-%).
30-60, 60-90, 40-75
ph of Hg oxygen affinity
affinity increases over pH range of 6-8.5. O2 held more tightly in alkaline situation, easily released when there is a lower pH. Bohr effect
hemoglobins oxygen affinity varies ______ with temperature so that at higher temp, more O2 unloaded, less bound by Hg.
inversely
2.3-biphosphoglycerate (2,3-BPG)
biproduct of the aerobic glycolytic pathway. present in red cells at concentration of ~5mmol/L