Erythrocyte Physiology Flashcards
three types of formed elements
white blood cells
red blood cells
platelets
hematocrit
the % of blood that is cells
RBC levels are sensed by the
kidney
- and a little in the liver
HIF-a
- what does it do in high O2 levels
- low O2 levels?
hypoxia inducible factor
- is ubiquinated and destroyed in sufficient O2 state
- accumulates in low O2 state
how does HIF act as a transcription factor
it binds with HIF-b in the nucleus and induces transcription and expression of erythropoietin which is then released in the blood
erythropoietin
principle regulator of erythropoiesis; produced by kidneys –> promotes erythropoiesis in bone marrow
the receptor for erythropoietin is connected to the _____ pathway
JAK2/STAT5 pathway
two requirements for adequate erythropoiesis
- adequate nutrition
- iron availability
microcytic anemia
low iron; smaller hemoglobins; pallor
the acidity of the stomach favors which form of iron
ferric form (Fe3+)
why do deficiencies in B12 and folic acid cause macrocytic anemia
cells are going through cell division but cannot make DNA, but they are still making proteins so the RBCs are getting larger
what do deficiencies cause in:
- iron
- B12
- folate
- microcytic anemia
- macrocytic anemia
- macrocytic anemia
what is the expected amount of oxygen to be carried by hemoglobin
1.34 mL O2 / g Hb
how to calculate oxygen capacity
1.34 mL x g of Hb
how to calculate oxygen content
oxygen capacity x % saturation
(1.34 x g Hb) x % saturation
what do RBCs need for
- flexibility
- ion transport
- maintaining iron in ferrous state
- preventing oxidation of Hb
ATP
how does the body compensate when O2 content is decreased
increased work load on heart; heart pumps more blood
In anemia, how are the levels changed:
- O2 sat
- Hb
- O2 capacity
- O2 content
- blood viscosity
- heart workload
- serum iron
- serum ferritin
- transferrin
- O2 sat unchanged
- Hb reduced
- O2 capacity reduced
- O2 content reduced
- viscosity reduced
- heart workload increased
- serum iron reduced
- serum ferritin reduced
- transferrin increased
in hemochromatosis, how are the levels changed:
- O2 sat
- Hb
- O2 capacity
- O2 content
- blood viscosity
- heart workload
- serum iron
- serum ferritin
- transferrin
- O2 sat unchanged
- Hb normal
- O2 capacity normal
- O2 content normal
- normal viscosity
- cardiomyopathy
- serum iron increased
- serum ferritin increased
- transferring reduced
Polycythemia
too many red blood cells
- thicker blood
- greater workload for heart
physiological polycythemia
low oxygen due to altitude/lung/heart disease
polycythemia vera (primary polycythemia)
bone marrow is making RBC when there is no need to; can be related to mutation in receptor for thrombopoietin
what is primary polycythemia characterized by
- EPO level
- RBC amount
- blood volume level
- viscosity
- cardiac output
genetic low EPO extra RBCs increased blood volume increased viscosity normal cardiac output
what is physiological polycythemia characterized by
- environment
- RBC amount
- cardiac output
high altitude adaptation
extra RBCs
normal cardiac output
