Hematopoeisis Flashcards
Anemia
A decrease in the amount of RBCs or hemoglobin in the blood
Can also be defined as a lowered ability for blood to carry oxygen
Slow onset anemia symptoms
Feeling tired
Weakness
Shortness of breath
Poor ability for exercise
Rapid onset anemia symptoms
Confusion
Feeling like you’re going to pass out
Increased thirst
Most anemias are due to deficiencies of what?
Iron (most common)
Vitamin B12
Folic Acid
Heme biosynthesis
Mainly in the liver and bone marrow
Pathway involves mitochondrial and cytoplasmic enzymes
The last stem involves incorporation of Fe++
Iron is a ‘one-way element’ - what does this mean?
Very little of it is excreted (0.5mg-1.0mg/day)
T/F - Any type of bleeding (including menstrual flow) will cause loss of iron from the body
True
T/F - Only the upper layers of skin cells contain iron
False - all skin cells contain iron
What forms of iron are absorbed?
Free ferrous ion (Fe++)
Heme iron
How is iron transported in the plasma?
It is transported by binding to transferrin
What form is iron stored in? Where is it stored?
Stored as ferritin in macrophages of the liver spleen and bone
And parenchyal liver cells
How is iron deficiency anemia treated?
Oral or parenteral iron preparation
Oral iron corrects the anemia just as rapidly as parenteral in most cases if iron absorption from the GI tract is normal
Folic acid and Vitamin B12 are necessary for what?
DNA synthesis - Hematopoeisis is especially sensitive
Anemias resulting from an insufficiency of vitamin B12 usually reflect what?
An absorption malady
What are some causes of B12 deficiency?
B12 deficiency in food (
How is vitamin B12 absorbed?
Combines with intrinsic factor (IF) forminga complex that resists digestion by GI tract enzymes
This complex is absorbed at the terminal ileum by pinocytosis
B12 is then transported to the liver for storage
What can deficiencies of Vitamin B12 cause?
Macrocytic anemia due to failure of maturation of RBCs
Neurological manifestations because the vitamin is also needed for the myelination of nerves
What is the most common cause of adult B12 deficiency
Loss of ability to absorb B12
- may be due to loss of IF
- may be due to other conditions that decrease production of gastric acid - which also plays a role in absorption of B12 from foods
What are the two types of Macrocytic anemia?
1) Cobalamin (B12 deficiency)
2) Folic acid deficiency
What can be causes of Folic acid deficiency?
Poor nutrition (Anorexia)
Malabsorption of small bowel
ETOH
Hemodialysis
Sickle-cell disease
Aka Sickle Cell Anemia
Hereditary blood disorder characterized by an abnormality in the oxygen-carrying protein hemoglobin
Leads to a propensity for the cells to assume an abnormal, rigid, sickle-like shape under certain circumstances
What causes the actual anemia associated with Sickle-cell disease?
The destruction of the blood cells because of their shape
Bone marrow attempts to compensate by creating new RBCs, but cannot match the rate of destruction
How long do normal RBCs function?
How long do Sickled cells funciton?
Normal = 90-120 days Sickle = 10-20 days
How can you treat sickle cell disease?
With treatment, people can now live to age 50+ (previously 20-40 yrs)
Can do a bone marrow transplant in severe cases, but it’s risky (5-10% mortality rate) and success is mild (85%)
Erythropoeitin (EPO)
Glycoprotein hormone that controls erythropoiesis, or RBC production
It is a cytokine for erythrocyte precursors in the bone marrow
Can be used as a therapeutic agent to treat anemia resulting form chronic kidney disease, inflammator bowel disease, and myelodysplasia from the treatment of cancer
Where is Erythropoeitin (EPO) synthesized, and why?
Produced in the kidney and is inducible by low oxygen or hypoxia?
Granulocyte-colony stimulating factor (GCSF)
or
Colony stimulating factor 3 (CSF 3)
Glycoprotein that stimulates the bone marrow to produce granulocytes and stem cells and release them into the blood stream
Granulocyte-macrophage colony stimulating factor (GM-CSF)
or
Colony stimulating factor 2 (CSF 2)
Monomeric glycoprotein secreted by macrophages, T cells, mast cells, endothelial cells and fibroblasts that functions as a cytokine
G-CSF and GM-CSF are used for what?
Used to treat chemotherapy induced neutropenia (low neutrophil count)
IL-11
Multifunctional cytokine isolated form bone-marrow-derived stromal cells
Key regulator of multiple events in hematopoeisis
Has been demonstrated to improve platelet recovery after chemotherapy-induced thrombocytopenia (loss of platelets)
Why do we give a shit about all of this?
Dentist might be the first health professional to observe symptoms of anemia in a patient because these symptoms might precede decreases such as a decline in Hb
Anemia might be a sign of serious hematopoietic disorder such as cancer, malnutrition, or drug toxicity
