Blood Components Flashcards
Function of Blood (3)
Transportation (gases, heat, nutrients, waste)
Protection
Regulation
Formed elements (3)
RBCs
WBCs
Platletes
Haemopoesis
= development of formed elements of blood
Site of haemoposesis before birth?
1st in yolk sac…later in spleen, thymus + lymph nodes of foetus
Main site of haemopoesis (last 3 months before birth)
red bone marrow
Describe red bone marrow
Highly vascularised connective tissue
In macroscopic spaces between trabeculae
0.05-0.1% of red bone marrow =
= PLURIPOTENT STEM CELLS
PLURIPOTENT STEM CELLS (derivative + function)
Derived from mesenchyme (tissue from which almost all connective tissue develop)
Have capacity to develop into many different types of cells
Red to Yellow Bone Marrow Transition?
All RED in newborns
As person ages rate of blood cell formation decreases
Red bone marrow in long bones becomes inactive (replaced with YELLOW bone marrow)
What can pluripotent stem cells divide into (what can they develop into?)
Myeloid Stem Cells (develop into: platelets, WBCs, RBCs)
Lymphoid Stem cells (develop into lymphocytes)
Precursor cells?
“…blasts”
Over several divisions
Develop into formed elements of blood
Progenitor cells? (what can they become)
No longer capable of reproducing themselves
Some becoming colony-forming units (CFU)
Become other types of blood cell but not themselves?
Name 3 types of Hematopoietic Growth Hormones
Erythropoietin (EPO)
Thrombopoietin (TPO)
Cytokines
Function of erythropoietin
Increases no. of red blood cell precursors
Mainly in kidneys
Function of thrombopoietin
Hormone produced by liver
Stimulates platelet formation