Hematopoiesis and its impairments

Question 1

What can excess dietary Zinc cause?

Answer 1

Microcytic anemia…. Serum oxidase to convert Fe2+ –> Fe3+ is copper dependent and excess zinc cause inhibit copper uptake

Question 2

What cofactor is necessary for Iron absorption

Answer 2

Vitamin C (Ascorbate)

Question 3

What is the Iron serum transport protein?

Answer 3

Transferrin

Question 4

What is the glycoprotein hormone that causes erythrocyte differentiation?

Answer 4

Erythropoieten (Epo)

Question 5

What stimulates Epo production?

Answer 5

Hypoxia

Question 6

Where is Epo produced?

Answer 6

Renal peritubular cells

Question 7

What 2 cytokines stimulate Jak-2 activity upon binding to their respective receptors?

Answer 7

Epo and Tpo

Question 8

Constitutive activation of the Jak-2 kinases can cause what?

Answer 8

Hematologic malignancy, blood clots

Question 9

What happens after ligand binds the Jak-2 kinases?

Answer 9

They move closer in proximity, phosphorylate/activate each other, and initiate downstream kinase cascades

Question 10

What precursor cell does a platelet come from?

Answer 10

Megakaryocyte

Question 11

What glycoprotein hormone stimulates thrombopoiesis?

Answer 11

Thrombopoietin (Tpo)

Question 12

What happens when Tpo binds to a megakaryocyte?

Answer 12

It stimulates production of megakaryocytes from immature precursors and megakaryocyte differentiation into platelets

Question 13

What is stored Iron bound to and where is it stored?

Answer 13

Ferritin in macrophages in the spleen, liver, and bone marrow

Question 14

What chromosome is the beta globin locus on?

Answer 14

Chromosome 11

Question 15

What causes megaloblastic anemia?

Answer 15

Folate and B12 deficiency

Question 16

How does B12 deficiency contribute to neurologic defects?

Answer 16

It is needed to convert homocysteine to Methionine. Methionine is needed to make myelin (This is what is thought to occur, Pathomas says something different, so there is disagreement)

Question 17

What can be elevated in the serum with B12 deficiency?

Answer 17

Methyl malonate

Question 18

What are the main 2 functions of Hepcidin?

Answer 18

Impairs release of Iron from storage and impairs Iron uptake

Question 19

Why is it important to not have unbound serum Iron?

Answer 19

Because it would aid bacterial proliferation and catalyze the formation of reactive oxygen species

Question 20

What would you measure if you were concerned someone had an abnormal amount of storage Iron?

Answer 20

Serum Ferritin level

Question 21

What happens in anemia of chronic inflammation?

Answer 21

Transferrin is pulled out of circulation. Ferritin will go up. This is all mediated by Hepcidin secretion

Question 22

What cytokine stimulates Hepcidin production in anemia of chronic inflammation?

Answer 22

IL-6

Question 23

What is Anisocytosis?

Answer 23

variation in size of erythrocytes; due to severe Iron deficiency

Question 24

What is Poikilocytosis?

Answer 24

variation in shape of erythrocytes; due to severe Iron deficiency

Question 25

What do both anisocytosis and poikilocytosis indicate?

Answer 25

severe Iron deficiency

Question 26

4 lab findings indicating Iron Deficiency Anemia?

Answer 26

1. decreased ferritin
2. increased TIBC
3. decreased serum iron (Fe)
4. decreased % saturation (of transferrin)