Pt 2 of Blood (RBCs) Flashcards
What is hematopoiesis?
The production of formed elements
- WBC and RBCs
Where does hematopoiesis take place?
In the bone marrow in a network of reticular CT
What is a Hemocytoblast?
A hematopoietic stem cell
–> The stem cell for all formed elements, and then cells become committed to a particular pathway
What is Erythropoiesis?
The formation of RBCs
What are the steps of Erythropoiesis?
- Stem cell (Hematopoietic stem cell; hemocytoblast)
- Committed cell (Proerythroblast)
- Developmental Pathway
Phase 1 - Ribosome synthesis (Basophilic erythroblast)
Phase 2 - Hemoglobin accumulation (Orthochromatic erythroblasts)
Phase 3 - Ejection of nucleus (Orthochromatic erythroblasts to a Reticulocyte) - Erythrocyte
Approximately how long does the production of RBCs take?
about 15 days
What is the difference between a reticulocyte and an RBC?
A reticulocyte is a slightly immature RBC. (in some anemias, Reticulocytes are increasingly made and are sent to the bloodstream while still immature)
What can a reticulocyte count tell you? (3)
- Provides info on the bone marrows ability to produce new RBCs
- Helps distinguish different causes of anemia
- Helps monitor bone marrow response and return of normal marrow function
Too few RBCs
Anemia
Too many RBCs
Polycythemia resulting in elevated blood viscosity
What is monitored and acts as a signal in hypoxia?
The level of O2 transport
How does the body regulate blood oxygen levels in hypoxia?
Once the body realizes smt might be wrong, the kidney (or/and liver) will release erythropoietin(EPO). This stimulates red bone marrow which increases the RBC count (starts with reticulocytes first then they mature). This allows for more O2 carrying ability of blood.
EPO stands for?
Erythropoietin
What is Erythropoietin? (1-2 days)
A glycoprotein produced in the kidneys. Stimulates RBC production.
–> important when immune system is at a low
It helps enhance maturation rate of committed RBC precursors. (more is released if–high altitude or pneumonia, increased demand, hemorrhage, insufficient Hb/RBC)
In renal failure patients what is an additional problem they face?
lack of EPO - RBCs can be 50% of normal :0. This can be helped by recombinant EPO