Hematopoiesis Flashcards
formation and development of blood cells
Hematopoiesis
PRENATAL HEMOPOIESIS
Yolk-sac phase of hemopoiesis:
It begins in the …………………of gestation.
3rd week
PRENATAL HEMOPOIESIS
Hepato-splenic phase:
during the…………………… Both hepatic and splenic continue until the end of gestation.
second trimester
Bone marrow phase or myeloid phase:
o It begins in the ……………… of pregnancy.
3rd trimester
After birth, hemopoiesis takes place only in the…………….and………………….
red bone marrow and lymphatic tissues.
most of marrow in adults is………………., is present in ……………………………
inactive yellow bone marrow,
diaphysis of long bones
Active red bone marrow In most of .,……………
fetus bones
Active red bone marrow In the adults……………
- Epiphysis of the long bones
- Ribs
- Body of vertebrae
Yellow inactive BM Is yellow in color
due to its ………………………….
high content of fat cells
In fetus: most of the marrow is ………………
the red type
Functions of Red active type
- Production of blood cells.
- Destruction of old RBCs.
- Storage of iron in
macrophages.
Functions of Yellow inactive type
- Storage of fats.
- In time of need as in
hemorrhage or
hypoxia, it can change
into active red type.
Structure of BM:
- CT stroma
- Blood sinusoids
- Hematopoietic cells
Stroma of Red bone marrow is a meshwork of …………. ,………..,…………….,………………
reticular cells, reticular fibers and collagen type I.
…………………….. are formed by a
discontinuous layer of endothelial cells
surrounded by macrophages.
Blood sinusoids
………………………. are composed of blood cells in various stages of maturation as well as macrophages
Islands of hemopoietic cells
Blood sinusoids surrounded by …………………….
macrophages
Components of the bone marrow section
- Megakaryocytes
- Blood sinusoids
- Developing blood cells
- Fat cells
All blood cells arise from a single type of ,……………………………………….. in the bone marrow that can give rise to all the blood cell types
pluripotent hemopoietic stem cell (PHSC)
Progenitor cells (colony forming unite;CFUs) Characterized by:
High mitotic activity and Less self renewal capacity
-Precursor cells (blasts) Characterized by:
Begin morphologic Differentiation, High mitotic activity and No self renewal
Mature cells Characterized by:
Clear morphologic differentiation and no mitotic activity
The blood sinusoids of the bone marrow are lined with
fenestrated endothelial cells
