Module 1: Normal blood components, production and erythrocytes Flashcards
Hematopoiesis
Production and development of blood cells, characterized by the constant restoring of the various cells of the blood
Hematopoietic system consists of (5):
Bone marrow Liver Spleen Thymus Lymph nodes
Types of cells maintained through hematopoiesis (3)
Erythropoiesis
Leukopoiesis
Thrombopoiesis
Erythropoiesis
Production of erythrocytes (rbc’s)
Leukopoiesis
Production of leukocytes (wbc’s)
Thrombopoiesis
Production of thrombocytes (platelets)
Myeloid Cells
NORMAL IN ADULTS
Blood cells produced in bone marrow
Include: erythrocytes, platelets, neutrophils, eosinophils, basophils, monocytes
Non-Myeloid Cells
NORMAL IN ADULTS
Blood cells produced outside the bone marrow (primarily in lymph nodes but CAN be produced in the bone marrow)
Lymphocytes
Medullary hematopoiesis
production of blood cells (myeloid cells) in the bone marrow
Extra-medullary hematopoiesis
Production of myeloid cells OUTSIDE the bone marrow
Usually in spleen or liver
ABNORMAL IN ADULTS
NORMAL IN FETUS-2MO.
If something is wrong with bone marrow, liver/spleen with kick in (can happen at any age)
3 phases of Hematopoiesis
Mesoblastic phase (2wk gestation-12wk gestation) Hepatic phase (6wks gestation-2wks post partum) Myeloid phase (20wk gestation-death)
Mesoblastic Phase
2wk gestation- 12wk gestation
In yolk sac and embryo primitive blood stem cells are formed
Hepatic Phase
6wk gestation - 2wks post partum
Liver and spleen involved in production of increasingly mature forms of RBC’s first, then granulocytes, then monocytes
Lymph nodes being to produce lots of lymphocytes
Bone/Bone marrow formation begins in 8th wk
Myeloid Phase
20wk gestation- death
Lymph nodes continue to produce lymphocytes
All other blood cells produced in bone marrow
Liver/spleen retain potential for hematopoiesis in adults but remain INACTIVE
Production location of myeloid cells in infants/children
Bone marrow
All bones contain red marrow
Production location of myeloid cells in adults
Bone marrow
Limited to iliac crests of pelvis, sternum, proximal ends od long bones, spinous process of the vertebrae
Production location of non-myeloid cells (lymphocytes) in all ages
Lymph nodes and other lymphatic tissue
Including spleen, tonsils, liver, AND MARROW
Hematopoietic Inductive Microenvironment
The bone marrow: complex, semi-fluid mix of various connective tissue cells
Includes fibrobasts, endothelial cells, blood cells, blood vessels and nerves
Red Marrow
ACTIVE
Much hematopoiesis
Equal numbers of fat cells and developing blood cells
Yellow Marrow
INACTIVE
Little hematopoiesis
Few blood cells and lots of fat
Liver and Hematopoiesis
Begins in 2nd trimester when it is the principle site of all cell production
In adults, liver functions as extra-medullary hematopoiesis, synthesizing transport proteins, storing minerals and vitamins, break down of hemoglobin
Spleen and Hematopoiesis
Largest lymphoid organ
Involved in production of cells during hepatic phase and during times of extra-medullary hematopoiesis.
Also removes old and damaged red cells and stores platelets
Affect on blood after spleenectomy
Missing speen no longer cleans/filters the blood
Increased platelet count
Increased damaged cells (poikilocytosis)
increased denatured hemoglobin inside RBC (bite cells, Heinz bodies)
Increased retained nuclear material in young cells (Howell-Jolly bodies)
Poikilocytosis
Damaged cells (abnormal shapes)
Heinz bodies
denatured hemoglobin inside RBC
Howell-Jolly bodies
retained nuclear material in young cells
Thymus
involved in the production and maturation of T-lymphocytes (for immunity)
Lymph nodes
Involved in the formation of new lymphocytes
Cells involved in Hematopoiesis (3)
Stem cells
- Reticulum cells
- -CFU-S
- -CFU-L
- -CFU-GEMM
- Blast cells
Stem cells
Primitive, formative, unspecialized blood cells with potential to change into several types of more specialized offspring
Reticulum cells
Undifferentiated cell that may turn into the following:
CFU-S
CFU-L
CFU-GEMM
CFU-S
Colony forming unit - Stem
AKA pluripotential, multipotent stem cells
Partly differentiated from reticulum cells
May change to CFU-GEMM or CFU-L
CFU-L
Colony forming unit - Lymphoid
May differentiate into various levels of lymphocyte precursors (T and B lymphoblasts and NK (natural killer) cells)
CFU-GEMM
Colony forming unit- Granulocyte, Erythroid, Monocyte, Megakaryocyte AKA Myeloid stem cell Committed to formation of myeloid cells May change into: CFU-Eo CFU-baso CFU-GM BFU-E CFU-E BFU-meg CFU-meg
CFU-Eo
form eosinophils
CFU-baso
form basophils
CFU-GM
form CFU-M and CFU-G
CFU-G and CFU-M
form myeloblasts and monoblasts
BFU-E
Burst forming unit - Erythroid
Form CFU-E
CFU-E
(erythroid) form pronormoblasts (rubriblasts)
BFU-meg
(megakaryocyte) form CFU-meg
CFU-meg
form megakaryoblasts
Blast cells
Earliest stages of blood cells that can be recognized as precursor to a particular cell line
Blast cell undergoes mitosis (under influence of enriched bone marrow environment)
Youngest blood cell that bone marrow will release into blood
Young forms of blood cell in peripheral blood =
indicate a serious disorder of hematopoiesis
Growth factors
Proteins that bine to receptors on cell surface resulting in activation of cellular maturation
Most important:
Colony stimulating factors (CSF) and interleukins (IL)
Erythropoietin (EPO)
thrombopoietin (TPO)
Cytokines
multifunctional chemical mediators secreted locally and exert hormone-like effects by interacting with surface markers on their target cell
Thus inducing or inhibiting cellular RNA or protein synthesis
Produced mainly by T lymphocytes and monocytes/macrophages
Lymphokine
cytokine produced by a lymphocyte
Monokine
cytokine produced by a monocyte or macrphage
GF producer cell: Monocytes and macrophages
Produce Interleukin-1
Activate and stimulate cytokine production by T lymphocytes and bone marrow stromal cells