Hematopoiesis Flashcards
(25 cards)
RBCs
- Structure
- Function
Structure: Non-nucleated
Function: Carries Hb which carries O2 to tissues
WBCs
- Structure
- Function
Structure: Nucleated
Function: Fights infection and/or provide immunity
Platelets
- Structure
- Function
Structure: Fragment of cytoplasm from its precursor cell
Function: Forms platelet plug to stop bleeding (doesn’t matter how severe)
3 phases of fetal hematopoiesis
- Mesoblastic phase
- Hepatic phase
- Myeloid phase
Mesoblastic phase
- Anatomic site of active cell production
- Gestational period of active cell production
- Occurs in yolk sac
- Begins at day 19 to week 5
- Only RBCs forming (Gower Hb), no WBCs
Hepatic phase
- Anatomic site of active cell production
- Gestational period of active cell production
- Liver (major site), but also spleen, LN, and thymus
- Week 5 to month 5
Myeloid phase
- Anatomic site of active cell production
- Gestational period of active cell production
- BM
- month 5 to birth
Normal red and yellow marrow distribution
- Newborn
- BM is 100% cellular
- More RBCs (more Hb) circulating compared to WBCs
Normal red and yellow marrow distribution
- Child (~5-7 years old)
- Doesn’t need as many circulating cells but needs more bone development
- Marrow starts receding at distal portions of long bones and gets replaced by yellow marrow/fat
Normal red and yellow marrow distribution
- Adult (~18 years old)
- 7 active sites of hematopoiesis
- Cellularity = 100 – patient’s age
7 sites of hematopoietic tissue in the normal adult
- Skull
- Shoulder blades
- Sternum
- Ribs
- Vertebrae
- Pelvis (most common)
- Proximal portions of long bones
3 anatomic sites of extramedullary hematopoiesis in order of frequency of involvement
- Spleen (most common)
- Liver
- LN
* NEVER THE THYMUS!
Reactive form of extramedullary hematopoiesis
We know the reason
Non-reactive form of extramedullary hematopoiesis
We don’t know the cause
Location of hematopoietic marrow
B/w or outside of venous sinuses (sinusoids)
Cell lines derived from CFU-GEMM
- Granulocytes
- Erythrocytes
- Monocytes
- Megakaryocytes
5 morphological changes that occur in most cells in response to cell maturation
- ↓ in cell size
- ↓ in nucleus: cytoplasm ratio
- Loss of nucleoli (lose by 2nd if not 3rd stage)
- Loss of cytoplasmic basophilia (RNA)
- Nuclear chromatin pattern (DNA) → fine to coarse
4 ways that BM can respond to increased demand fro blood cells
- Maturation time can be decreased
- Decrease in generation time
- Expand into fatty areas of red marrow
- Expand into yellow marrow
* Last resort…extramedullary hematopoiesis (spleen → liver → LN)
Major function of cell membrane
- Separates cell from outside environment
- Detects hormonal signals facilitating cell-to-cell recognition
- Location of surface markers (CD markers) for cell identificaiton
Major function of Golgi complex
- Packages and sorts cellular products = “directs traffic”
- Lies next to nucleus
Major function of endoplasmic reticulum
Stores and transports fluids
Major function of ribosomes
- Site of protein synthesis = RNA
- Gives cytoplasm blue color in less mature cells
Major function of mitochondria
Energy source for cells
Major function of lysosomes
Contains hydrolytic enzymes that aid in cellular digestion during phagocytosis
