Chap 4 Flashcards
Hematopoiesis
Differentiation
The process that shapes a immature cell’s destiny.
Commitment
When an HSC commits to a cell lineage.
Maturation
The cell’s process of growing.
Hematopoiesis
process of Blood cell production, development, and replacement, that usually occurs in the BM.
What is the purpose of Hematopoiesis?
Allows system to respond to stimuli like infection, bleeding, or hypoxia, by increasing production of the needed cell line.
HSCs can differentiate into what?
Lymphoid or Myeloid Lineages
HSCs are directed to 1 of 3 possible fates?
Self-Renewal
Differentiation
Apoptosis
The process of replacing active marrow by adipocytes (yellow marrow cells) during development is called?
Retrogression
Adipocytes
Large cells W/ a single fat vacuole and play a role in regulating the volume of marrow in which active hematopoiesis occurs.
What secretes cytokines or GFs that positively stimulate HSC #s and bone homeostasis?
Adipocytes
Medullary sites?
Origin of blood cells and sequential sites of normal blood production w/n BM.
Extramedullary Sites?
Blood cell production in Hematopoietic tissue other than BM (Liver, Spleen), and provide compensatory mechanism to blood cells in time of need.
Primary production sites of a fetus?
Yolk Sac
Liver and Spleen
BM (All Bones)
Primary production sites of an adult?
*Child up to Teens- All bones
*18+ - Flat Bones (Sternum, Ribs, Pelvis, Vertebra, Skull)
*Adults- BM
Hematopoiesis stages in life
Yolk Sac(19days-2.5 fetal months)
Spleen & Liver(2.5-6 fetal months)
BM(Around 5th fetal month)
Spleen & Liver(stop @ birth)
All bones (until teen years)
Flat bones (20-50)(TIbia, Femur, Lymph Nodes, Rib, Sternum, Vertebra)
Just BM(Adults)
1st stage of Hematopoiesis?
Mesoblastic
Mesoblastic begins in the mesoderm of?
Yolk Sac and forms Erythroid cells
How long does production take place in the yolk sac?
19 days to 2.5 fetal months
Angioblasts
Cells that surround the cavity of the yolk sac and eventually form blood vessels.
Fetal Hemoglobins found in these embryonic cells?
Gower-1
Gower-2
Portland
The second phase of hematopoiesis in a fetus?
Hepatic Phase
When does the hepatic phase begin?
5-7 gestational weeks
How is the hepatic phase characterized?
Recognizable clusters of Eryths, Grans, and Monos
Major site of hematopoiesis in the 2nd phase?
Liver
When does the liver take responsibility for hematopoiesis?
2nd fetal month
When does the hepatic phase start and stop?
3-6months
Where else does hematopoiesis take place during the Hepatic phase?
Spleen, Kidneys, Thymus, Lymph Nodes
Hematopoietic Precursor Cells (HPCs)
Stem Cells(SCs)/pluripotential(PP)
Lymph/Myelo Progenitor Cells (MPCs, LPCs).
Maturing Cells (MCs)
T or F: SCs are morph recognizable
False
How much of the total hemopoietic precursors are SCs?
0.5%
SCs are capable of _________differentiation W/ a stable population size?
A.Multilineage
B. Single Lineage
C. No Lineage
D. Alternating Lineage
Multilineage
Lymphoid/Myeloid progenitor cells (LMPCs) make up how much of the precursors?
3%
The population of Lymph/Myelo precursors are amplified by?
Proliferation
The LMPCs are not _______but are multipotential.
A. Recognizable
B. Unrecognizable
C. Normal
D. PP Cells
Recognizable
Maturing Cells make up how much of the total precursors?
> 95%
Like the LMPCs, maturing cells population is amplified by?
Proliferation
Maturing cells are morph recognizable and are _____cells?
A. Non-Committed
B. Unresponsive
C. Agressive
D. Committed
Committed
Cytokines
GFs secreted by cells for the purpose of cell-cell comms.
GFs stimulate PP SCs to?
Proliferate and Differentiate
GFs promote cell survival by surpressing which mechanism?
Apoptosis “Cell Death”
3 examples of Cytokines?
CSFs
Interleukins
Lymphokines
CSFs
Colony stimulating factors.
Regulate blood cell development.
G-CSF
Stimulates Granulocyte(Gran or Grans) production
G-CSF can be used to treat cancer and AIDS PTs W/ low WBCs, what is the name of the medicine?
Neupogen
GM-CSF
Stims Gran/Macro production
GM-CSF can treat?
PTs w/ cancer and low WBCs, named Leukine.
Erythropoietin (EPO)
Stims Eryths prod.
EPO can be used to treat PTs w/?
Chronic Anemia due to renal failure, or increase RBCs prior to surgery. Professional athletes can’t use; med name is Epogen or Procrit
Grans and PLTs exist in 2 pools?
Circulating and Marginal
Circulating Cells are?
Mature and incapable of mitosis, except lymphs. Functional w/n circulation
Where are the circulating cells in-transit to?
To the tissues
What do Marginal Pool Cells do?
Adhere to the walls of blood vessels and are ready for diapedese.
How are grans split in there pools?
50% in circulation and 50% are marginating
How are PLT cell line pools split?
70% of PLTs in circulation and 30% are stored in the Spleen.
What 1 cell lineage is always in circulation in the PB and in a functional stat in the BM pool?
Erythrocytes
Name 2 bone derived cells found in the BM?
Osteoblasts
Osteoclasts
Osteoblasts are responsible for?
The formation, calcification, and maintenance of the bone structure.
Osteoblasts are large irregularly shaped cells in the BM that can be confused with?
Plasmacytes or malignant cells.
Osteoclasts are responsible for?
Absorption of bone and assists in the degradation of bone.
Osteoclasts are giant multinucleated, irregularly shaped phagocytic cells in the BM that are confused with?
Megakaryocytes.
