Developmental Hematology Flashcards
The hematopoetic stem cells which lead to all blood formed elements have maximum (1) ability but are only minimally (2) and tend to not divide as quickly as more differentiated cells
- self-renewal
2. differentiated
When stem cells divide they usually divide into?
a stem cell which remains pluripotent and a second cell which can differentiate along a more specific lineage
Stem cells express (1) and respond to (2)
- CD34 and c-kit
2. stem cell factor (SCF) and IL-6.
The pluripotent stem cell can differentiate either along the (1) pathway
- lymphopoetic or myelopoetic
In the lymphopoetic pathway, cells are initially (1) positive and later B cells develop surface immunoglobulin which switches class from (2) to (3)
- CD34 and TdT (terminal transferase)
- IgM
- IgG or IgD
The most differentiated B cells are (1) cells which produce large quantities of specific clonal immunoglobulins.
- plasma
In the myelopoetic pathway, the precursors can differentiate into (1) in response to (2) or (3) in response to (4)
- normoblasts (erythrocyte progenitors)
- erythropoietin
- megakaryocytes
- thrombopoetin.
Megakaryocyte (2) becomes (1) in response to other factors.
- cytoplasm and membrane
1. platelets
Myeloid differentiation: (1) confers eosinophilic differentiation
- IL-5
Myeloid differentiation: (1) confers granulocytic differentiation
- G-CSF
Myeloid differentiation: (1) confers monocyte differentiation
- M-CSF
Erythropoiesis is perhaps the ultimate example of the inverse relationship between cell proliferation and differentiation since completely formed red blood cells lose their (1) so they can no longer divide or synthesize proteins.
- nuclei and ribosomes
Erythroid progenitors can basically either form (1) which are large collection of red cell progenitors or they can form (2) which are smaller populations
- bursts
2. colonies
During human embryologic development, blood formation begins initially in the (3) but then the (1) are the major sites for red cell production during the (2) trimester.
- blood islands in extraembryonic tissues
- liver and spleen
- second
When does the bone marrow become the major site of red cell development?
during the third trimester and after birth
In certain disorders with poor erythropoesis there can be a reversion to (1) hematopoesis in adult life which can involve a number of organs but most commonly involves (2)
- extramedullary (outside bone marrow)
2. liver or spleen
Fetal red blood cells also express embryonal (1) and fetal hemoglobin (2) prior to the predominant production of adult hemoglobins (3) after birth and in adult life. This phenomenon is called (4)
- HBepsilon and HAzeta
- HBgamma
- delta and beta
- hemoglobin switching.
embryonal hemoglobgin
HBepsilon and HAzeta
fetal hemoglobin
HBgamma
Adult hemoglobin
delta and beta
In patients with thalassemia or sickle cell anemia, the persistence of (1) can improve oxygenation to tissues.
- fetal gamma hemoglobin
nucleated red cells
normoblasts (orthochromatic erythroblast)
red cells with ribosomes for Hb synthesis but without nuclei
reticulocytes (polychromatic erythrocytes
Stem cells attached by (1) junctions to
(2) lining the inner surface of
bone cavities
- adherens
2. osteoblasts
bursts vs. colonies
bursts - high proliferation rate; more primitive
colonies - lower proliferation rate, high differentiation stage; later lineage cels produce colonies
Hematopoesis in children versus elderly
Occurs in bone marrow of:
Children - long bones (tibia and femur)
Elderly - central bones vertebrae and pelvis)
Fetal hemoglobin is resistant to (1) which makes it easier to measure in the lab
- alkali
What factors shift the oxygen dissociation curve of hemoglobin?
An increase in CO2, acid, DPG, exercise and temperature make the curve go to the right. “CADET face right”
Embryo vs. fetus;
Embryo–> fertilization to 8th week of gestation;
Fetus–> 8th week to birth;
Embryo vs. fetus vs. adult; compare Hb types.
Embryo–> “Gower” hemoglobin consisting of EPSILON and A Zeta chain;
Fetal–> fetal Hb consisting of alpha2 and GAMMA2
Adult Hb–> alpha 2 and BETA2 (predominantly) or alpha2 and DELTA2
Benign vs. malignant tumor clonality
Benign: multi-clonal
- Like inflammatory or benign lymphoproliferative type multi-clonal - Malignant: Expansion of a single clone -> mono-clonal
Why is chemotherapy not more successful?
Targets highly proliferative cells such as malignant cell, but also kills of some hematopoietic stem cells; since the HSC dont divide as often, it leaves patients at risk for infection, etc.
Bone marrow vs. blood vs. tissue
Primitive cells found in bone marrow;
Blood–> only DIFFERENTIATED cells here; if you see primitive cells then may be lymphoma;
Tissue–> mast cells, macrophages, plasma cell, etc
Myeloid progenitor–>G-CSF; GM-CSF
G-CSF–>Basophil and neutrophil
GM-CSF–> nonspecific;
Platelets are the cytoplasm and membrane of megakaryocytes; no 1). But, they do have 2)
1) NUCLEI
2) mitochondria (since need E for E-depdent processes.
Mature RBCs vs. platelets
BOTH have no nuclei;
Platelets have mitochondria; RBCs have NO mitochondria or any organelles;
As erythrocytes mature, they 1)_____; 2)_____ 3)decrease in ___
1) lose nuclei;
2) lose organelles;
3) membrane, proteins, and cytoskeleton
As erythrocytes mature, histologically, start off 1) but as lose nuclei and gain Hb get more 2)
1) blue
2) RED
First place where hematopoiesis occurs in fetus
yolk sac (early) then liver and spleen (second trimester) then bone marrow (third)
Adult hematopoiesis
Vertebra and pelvis; followed by STERNUM
B cell development–> 1) and 2) as early markers; first secrete Immunoglobulin 3) which then classs switch to 4)
1 and 2) CD34 and TDT
3) IgG
4) IgM and IgD
B cell development–> antigen independent in ____
antigen dependent in _____
1) bone marrow;
2) peripheral lymphoid tissues
