Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IHO Week 1 > IRON Metabolism > Flashcards

IRON Metabolism Flashcards

1
Q

In post-menopausal female or male, if they have iron deficiency with no obvious cause. . .

A

. . you HAVE to look in the GI tract - must send to colonoscopy and not miss a GI bleed!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the mechanism by which anemia of chronic disease works?

A
  • There is too much hepcidin

- Bioavailability is the issue

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is ferritin?

A

Your storage iron

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the concept of heme iron and ferric iron in iron absorption (why vegetarians don’t absorb as well)?

A
  • Dietary iron is present in two forms in the diet
  • Heme iron (hemoglobin and myoglobin in beef, chicken, fish, etc.) = best absorbed [O2 binds Fe2+ better- ferrous]
  • Non-heme iron/Fe3+ (cereal, vegetables) = taken up less avidly
  • Greater than 1/3 of iron is from fortification of flour
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Hepatocyte?

A

-Master regulator

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Hepatocyte?

A
  • Master regulator via its production of hepcidin

- Hepcidin is the keystone regulator of systemic iron homeostasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is Hepcidin?

A
  • Master regulator of systemic iron homeostasis
  • 25 AA polypeptide produced in response to inflammation (AOCD, IL6) and increased iron stores
  • Binds to ferroportin and triggers its internalization and degradation to lysosomes
  • Decreases Fe release from macrophages, enterocytes, and hapatocytes
  • Results in increased IC iron
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What does Hepcidin deficiency cause?

A

Iron overload

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What does excess hepcidin cause?

A

AOCD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What happens in iron overload?

A
  1. When a lot of iron is around, transferrin saturation is high
  2. Hepcidin will then be generated
  3. Hepcidin will bind the enterocyte in the liver - this doesn’t allow for the release of iron at the enterocyte.
  4. No absorption occurs and no iron gets into the circulation!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What happens in the body when you have excess iron?

A

More hepcidin is produced!

-Hepcidin binds to duodenal enterocytes and triggers their degradation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

When there is high iron, transferrin saturation is ____. When there is low iron, transferrin saturation is ___.

A

high, low

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

When transferrin saturation is low. . .

A

. . .the cell does not make hepcidin.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the primary therapy for hemochromatosis?

A

Hemachromatosis = too much iron and the number one way to get rid of it = REMOVING BLOOD FROM PATIENT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Increase in transferrin saturation signals to hepatocytes to increase hepcidin expression via . . .

A

a HFE and TfR2 dependent manner.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is TIBC?

A

Total iron binding capacity - number of iron binding sites on transferrin molecules - serum transferrin concentration

17
Q

What iron indices are found in iron deficiency?

A

Decreased Serum iron
Increased TIBC
Decreased Transferrin saturation
Decreased Ferritin

18
Q

What iron indices are found in anemia of chronic disease?

A

Decreased Serum Iron
Decreased TIBC
Decreased Transferrin saturation
Increased Ferritin (optional)

19
Q

What iron indices are found in hemochromatosis?

A

Increased Serum Iron
Decreased TIBC
Increased Transferrin saturation
Increased Ferratin

20
Q

When you have low iron. . .

A

. . .body increases transferrin!

21
Q

What is the mechanism by which anemia of chronic disease works?

A
  • Increased inflammatory cytokines (IL-6, IL-1B, etc.) induce hepcidin
  • There is too much hepcidin
  • Bioavailability is the issue
22
Q

AOCD Dx

A
  • Chronic inflammatory process
  • -Increased ESR, CRP
  • -Look at other acute phase reactants (reduced albumin, transferrin)
23
Q

What is the treatment for hemochromatosis?

A

Phlebotomy!

24
Q

What is the mechanism for which HFE mutations cause hemochromatosis?

A

HFE is a transmembrane protein that regulated hepcidin expression.
-Mutation results in lack of interaction of HFE with TFR2 and reduced cell surface expression

25
Q

What is the mechanism for which HFE mutations cause hemochromatosis?

A

HFE is a transmembrane protein that regulates hepcidin expression.

  • Mutation results in lack of interaction of HFE with TFR2 and reduced cell surface expression:
  • -Decreased hepcidin expression
  • -Increased FE absorption
  • -Increased serum iron and Tf Sat
  • Decreased storage of iron in macrophages
26
Q

What is hereditary hemochromatosis?

A
  • HH, or primary iron overload is a collective label for a group of autosomal inherited iron overload disorders
  • Hereditary conditions affecting the hepcidin/ferroportin access
27
Q

What is type I hereditary hemochromatosis?

A

Classical HFE gene mutations resulting in cysteine-to-tyrosine substitution at amino acid 282 (C282Y) or an aspartate-to-histidine substitution at amino acid 63 (H63D)

28
Q

What is HFE?

A

A transmembrane protein belonging to MHC Class I and expressed at high levels in the liver

29
Q

What does hereditary hemachromatosis cause?

A
  • Sever symptoms not usually seen until decades or iron loading have passed
  • Classic triad
  • –DM
  • –Hepatomegaly
  • –Hyperpigmentation
  • Death from cirrhosis, hepatocellular carcinoma, or CHF
  • Goal is to make dx and tx in pre symptomatic stage
30
Q

What does hereditary hemachromatosis cause?

A
  • Sever symptoms not usually seen until decades or iron loading have passed
  • Classic triad
  • –DM
  • –Hepatomegaly
  • –Hyperpigmentation
  • Death from cirrhosis, hepatocellular carcinoma, or CHF
  • Goal is to make dx and tx in pre symptomatic stage
  • Normal life expectancy if phlebotomy caught before DM or cirrhosis
31
Q

HFE Genetic Defect:

A
  • Penetrance C282Y/C282Y incomplete

- –Elevated serum ferritin in

IHO Week 1 (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions