RBC Wed Prereading Flashcards Preview

Heme/Lymph > RBC Wed Prereading > Flashcards

Flashcards in RBC Wed Prereading Deck (33):
1

List some major sources of iron

red meat, shellfish, fish-heme iron
enriched cereals, beans, tofu, seeds, potatoes, green veggies, dried fruit-non heme iron

2

When are plasma hepcidin levels high?

when stores are full of iron and erythropoietic activity is normal

3

What does high plasma hepcidin cuase?

downregulation of ferroportin and trapping of most of the absorbed iron

4

When are plasma hepcidin levels low?

when body iron stores are depleted or erythropoiesis is stimulated

5

What happens when hepcidin leves are low?

ferroportin activity increases, allowing a greater fraction of absorbed iron to be transferred into plasma transferrin

6

What protein allows for entry of non-heme iron?

DMT-1 divalent metal transporter 1

7

What protein allows for entry of heme?

heme transporter

8

What cofactor is required for the asorption of non-heme iron?

vitamin C

9

What enzyme reduces ferric to ferrous? What is it dependent on?

duodenal cytochrome B
ascorbic acid (vit C)

10

What stores iron in dueodenal cells?

ferritin

11

What transports ferrous across the basal later membrane of duodenal cells?

ferroportin 1

12

What converts ferrous back to ferric once it has crossed the basal lateral membrane?

hephaestin

13

What molecule transports ferric in the blood?

transferrin

14

How do other cells take up ferric?

transferrin receptor-->endocytosis-->DMT1 to get out of endosome

15

What molecule regulates the release of iron from the duodenal epithelial cells?

hepcidin

16

What are hemosiderin granules?

partially degraded ferritin-iron complexes
this is the main storage form for iron during overload

17

How is iron recycled?

by marophages

18

What are major ways iron is lost?

shedding of intestinal/skin cells
menstruation
abnormal bleeding
pregnancy

19

What is the cause of megaloblastic anemai?

inability to synthesize adequate amounts of purines and thymidylate triphosphate for DNA synthase
folate def, vit B12 def, methionine synthase def

20

What effect does methyltrexate have on purine synthesis?

inhibits dehydrofolate reductase, limiting puruine and thymidylate synthesis
causes drug induced megaloblastic anemia

21

Sources of folate

veggie (esp dark green)
fruits, grains, nuts, beans, dairy, seafood, meat
cereal, rice

22

sources of vitamin B12

meat, shellfish, milk, eggs
vegans must get supplement

23

What role does saliva play in B12 uptake?

Salivary haptocorrin/R protein needed

24

What cells secrete intrinsic factor?

parietal cells

25

What is anemai caused by B12 deficiency formally called?

perniscious anemia

26

What is anemia of chronic disease (inflammation)?

mild to moderate anemia associated with inflammatory disorders, infection, malignancy

27

Common diseases associated with ACD?

chronic microbial infections
chronic immune disorders
Neoplasms

28

ACD features?

reduced transport of iron to erythroid precursors, reduced or ineffective erythropoiesis, normal or increased iron stores

29

Mechanism of ACD?

increased levels of IL-6 upregulares hepatic production of hepcidin, this leads to internalization nad lysosomal degradation of ferroportin and reduced release of iron into plasma

30

Blood smear in ACD?

no noticeable polychromasia or increased anisocytosis
RBCs normochromic or nomocytic

31

BM in ACD?

generally normocellular, may show diminished erythropoiesis
lack of sideroblasts

32

What happens to ferritin levels during ACD? Transferrin?

ferritin often elevated
transferrin reduced

33

Is total iron binding capacity elecated in ACD?

no