Hematopoiesis and Cell Morphology Flashcards
Where is hematopoiesis in a fetus
the yolk sac, liver and spleen
Where is hematopoiesis in after birth
the bone marrow
What are hematopoietic tissues
bone marrow, lymph nodes, spleen, liver, thymus
What is red marrow
contain hematopoietic progenitors and developing cells
What is yellow marrow
inactive, mostly fat cells, macrophages and mesenchymal cells
What are the stromal cells in the marrow
endothelial, adipocytes, macrophages, lymphocytes, osteoblasts, osteoclasts
What is EPO
secreted in hypoxic states by the interstitial cells of the kidney to promote RBC production in the marrow
What is thrombopoietin
secreted by the liver and kidneys to develop megakaryocytes into platelets
What are cytokines
trigger differentiation/maturation
What does estrogen do in erythropoeisis
promotes erythropoiesis
What do androgens do in erythropoeisis
promote erythropoiesis by promoting EPO production
What do thyroid hormones do in erthropoiesis
promote erythropoiesis through increased HGB production
What are hematopoitic stem cells
cells that can self-renew to produce more HSC, mature into pluripotent or precursor cells that give rise to WBCs, RBCs and PLTs
What are the intrinsic factors that cause HSC differentiation
genes and genetic composition of the cell
What are the extrinsic factors that cause HSC differentiation
cytokines, growth hormones, hormones
What cells are in the stem cell pool
hematopoitetic stem cells
What cells are in the proliferation pool
common myeloid pregenitor, granulocyte macrophage progenitor cells, myelocytes
What cells are in the maturation pool
cells read for release into the peripheral blood (metamyeloctes, bands and segmented)
What are marginating cells
loosely lovalized to the walls of capillaries in tissues such as the liver, spleen and lung
What are physiological causes of leukocytosis
strenuous exercise, emotional stress, labour, increased epinephrine
What are pathological causes of leukocytosis
bacterial infection, neoplasms, acute hemorrhage, tissue damage, drugs and toxins, inflammatory disorders
What are primary lymph tissues
thymus, bone marrow, antigen independent maturation
What are secondary lymph tissues
spleen, lymph nodes, tonsils, mucosal lymph tissues, antigen dependent
Where are T cells made
thymus
Where are B cells made
bone marrow
What are the CD markers for B lymphocytes
34, 45, 19, 20, 22, 24, kappa, lambda
What is the purpose of B lymphocytes
produce antibodies and memory cells as well as cytokines for T-cell regulation
What are the CD markers for T lymphocytes
34, 45, 1, 2, 3, 4, 5, 7, 8, 25
Where do platelets originate from
the myeloid cell line
What are the requirements for erythropoiesis
iron, B6, B12, folate, EPO
How long do RBC survive in circulation
120 days
What are the steps of erythropoiesis
- begins in the bone marrow
- reticulocytes are released into blood stream where they mature and circulate for ~120 days
- old and damaged erythrocytes are phagocytized by macrophages in the bone marrow, liver and spleen
- the globin is metabolized into amino acids and the cellular components are recycled
- the heme portion is broken down into biliverdin for transport and iron binds to transferrin for transport
- unused heme groups can be recycled or converted into bilirubin and used to make bile in the liver. Iron can be reused or transferred to ferritin for storage in the liver
What are transmembrane proteins of RBCs used for
transport and adhesion sites
vertical membrane support
signal receptors
anchor bilayer to cytoskeleton
What are peripheral proteins of RBCs used for
lateral membrane stability and blood group proteins
What is cholesterol used for in RBCs
tensile strength, deformability at low temperatures, stability, anchoring proteins
What are phospholipids used for in RBCs
fluidity and elasticity
How does the RBC produce energy
the embden-meyerhoff pathway
What is the hexose monophosphate shunt
it prevents oxidative damage to the cell by keeping proteins and membranes functional. It also keeps iron in the ferrous state
What are the steps of the hexose monophosphate shunt
- G6P is reduces NADP to NADPH using G6P dehydrogenase
- NADPH converts glutathione to reduced glutathione
- reduced glutathione reduces and breaks down hydrogen peroxide to water and carbon dioxide
What is the methemoglobin reductase pathway
maintains hemoglobin iron in the ferrous state for effective oxygen transport
How can ferric heme iron be treated
infusing patients with saturated oxygen or 1% methylene blue
What are the steps of the methemoglobin reductase pathway
- G3P is converted to 1-3 biphosphoglycerate
- G3P dehydrogenase reduces NADP to NADPH
- Methemoglobin reductase uses NADH to reduce methemoglobin to hemoglobin
What is the Rapoport-Leubering Pathway
produces 2,3 biphosphoglycerate which competes with oxygen for the heme iron and allows oxygen to dissociate
What does effective hemoglobin production require
protoporphyrins, globin chains, iron
What are required for protoporphyrin production
glycine, succinyl CoA, vitamin B6, ALA synthase
Where are alpha chains used
all hemoglobin
Where are beta chains used
normal adult hemoglobin
Where are gamma chains used
embryonic, fetal and neonatal hemoglobin
Where are delta chains used
variant adut hemoglobin (A2)
Where are epsilon chains used
embryonic hemoglobin
Where are Zeta chains used
embryonic hemoglobin
What are the hemoglobin quantities at birth
60-90% HGB F
10-40% HGB A
What are the hemoglobin quantities from 6months - adulthood
1-2% HGB F
>95% HGB A
<3.5% HGB A2
Where is iron absorbed
the duodenum
In what form is iron absorbed
the ferrous form
How is iron usage regulated
Copper, Zinc, Transporters (hepcidine)
What is hemolysis
premature destruction of RBCs
What can cause hemolysis
defect in RBCs
defect in environment
What are clinical features of hemolysis
pallor, lethargy, jaundice, splenomegaly, gall stones, dark urine, bone deformity, leg ulcers
What are lab findings of hemolysis
increased serum bilirubin
increased urine urobilinogen
increased fecal stercobilinogen
absent serum haptoglobins
increased lactate dehydrogenase
reticulocytes
bone marrow erythroid hyperplasia
schistocytes
What is intravascular hemolysis
breakdown of red blood cells in circulation
What is extravascular hemolysis
excessive removal of red cells by the RE system in the spleen and liver
