Topic 5.1 Flashcards
RBC count in females
4.4 million/microL
RBC count in males
5 million/microL
Platelets count
300,000/micro L
WBC count
7000/micro L
Neutrophil granulocyte count
4000/microL
Eosinophil granulocyte count
200/microL
Basophil granulocyte count
50/microL
Monocyte count
500/microL
Lymphocyte count
2000 /microL
Daily production of blood cells by constitutive lymphohematopoiesis
10^11 blood cells (75% WBC, 25% RBC)
What are the 6 main functions of blood?
- Thermoregulation
- Oxygen transport
- Metabolites and nutrients
- Acid-base balance
- Hemostasis
- Endocrine function
What is the lifespan of RBC and how are they cleared form circulation?
120 days, cleared by the spleen
What is the lifespan of platelets and how are they used?
10 day lifespan, used continuously by the micro and macro injuries in vasculature
What is the lifespan of WBC and how are they used?
Hours to 20 days, used continuously by immunological processes
What are the 2 types of lymphohematopiesis?
Constitutive hematopoiesis and stress hematopoiesis
What does stress hematopoiesis induce?
Lineage specific : hypoxia -> RBC, infection -> granulocytes
Main sites of hematopoiesis in fetus (2)
LIver and yolk sac
Main sites of hematopoiesis in adult (2)
axial skeleton mostly, then distal long bones
What are the 2 types of bone marrow?
Yellow marrow and red marrow
What does yellow marrow produce?
inactive, mainly fat cells
What does red marrow produce?
RBC actively
What are the 4 properties of Hematopoietic stem cells?
- Asymmetric division
- Self renewal
- Multipotency (system specific)
- Surface markers
What are the 2 markers on HSC in humans?
c-kit and CD34
What is the c-kit marker?
receptor tyrosine kinase, binds to stem cell factor for growth
What is CD34 marker?
cell migration / adhesion regulator
What are the first 3 cells (just a straight line) in hematopoiesis?
- LT-HSC
- ST-HSC
- MPP (multipotent progenitor)
What does MPP divide into?
CLP (common lymphoid progenitor) and CMP (common myeloid progenitor)
What does CLP divide into?
- TP (T progenitor) then Pro-T
- TB (B progenitor) then Pro-B
- NKP (natural killer progenitor) then NK
- MP
What does CMP divide into?
- GMP (granulocyte progenitor)
- MEP (megakaryocyte erthrocyte progenitor)
What does MEP divide into?
MKP and Erythroblast
What is the stage between multipotent and unipotent?
Oligopotent
What are iPS?
induced pluripotent cells : somatic cells (unipotent) reprogrammed to be pluripotent
What are the 2 stages of regulation of hematopoiesis?
early stage and later stage
How is early stage regulation of hematopoiesis?
Many factors that have overlapping effects. Doesn’t matter if one factor is missing
How is late stage regulation of hematopoiesis?
Fewer factors : more specific and sensitive - at the unipotent part
What are the 3 ways of regulating hematopiesis?
- Surface molecules, cell to cell contacts
- Local humoral factors (paracrine)
- Humoral regulators form the bloodstream
(2 and 3 are by cytokines)
What are cytokines? What effect can they have?
molecules (often cytokines) that have effect on cells specifically. They can have simple effects or pleiotropic effects (on different cell types)
What is EPO?
erythropoietin, acts to diff to RBC
What is GM-CSF?
sargramostim / granulocyte monocyte colony stimulating factor
What is G-SCF?
Filgrastim (myeloid)
What are “niches”?
where cells learn / maturate : special environment
What are the maturing forms of GMP?
Monoblast, Promonocyte, Monocyte, Macrophage + dendritic cell
Which cells also directly comes from GMP?
osteoclast
How long does it take for monoblast to mature to monocyte?
6 days
What do proerythroblasts come from?
MEP
How long does erythropoiesis last?
7-10 days
What are the 6 steps of erythropoiesis?
- proerythroblast (EPO receptor)
- basophil erythroblast
- polychromatophil erythroblast
- orthocromatic
- reticulocyte
- erythrocytes
What are the 3 required elements for erythropoiesis?
- Fe2+
- Vitamin B12
- Folic acid
At what step of erythropoiesis do cells appear in the blood?
At the step of reticulocytes
What is the role of macrophages in erythropoiesis?
they form erythropoietic islands : 1 macrophage nurtures 10-15 blast cells in its membrane
What molecule / receptor is needed for blasts to attach to the macrophages in the islands?
NHC1
Which organ secretes EPO?
the kidney, in cortical cells - and a tiny bit in the liver
WHat is the role of EPO?
It regulates the production of RBC
What does the b antigen have?
It has galactose
What does the A antigen have?
It has N-acetyl-galactosamine
What are the 4 main phenotypes?
A, B, AB, O
How are A and B phenotypes inherited?
Codominantly
What antigen is present on every RBC?
H antigen
What is Landsteiner’s rule?
Individuals will form immune antibodies to ABO blood group antigens they do NOT possess
What is the Rh blood group system?
protein group of the membrane of RBC
What are the 5 most important antigens of Rh system?
D, C, c, E, e
What is special about the D antigen?
it is very immunogenic (IgG)
