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Hematology > Iron, Folate and B12 Metabolism > Flashcards

Iron, Folate and B12 Metabolism Flashcards

1
Q

R protein

A

Binds to B12 in the mouth

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2
Q

Parietal Cells

A

Release intrinsic factor which aids in intestinal B12 absorption

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3
Q

B12 is absorbed in the ….?

A

ILEUM!@!@

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4
Q

Iron is naturally Fe__+

A

Fe3+

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5
Q

What makes iron become Fe2+?

A

Vitamin C. It must be in this state to be absorbed.

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6
Q

How is iron metabolized?

A

Its not. Duh. It is lost through bleeding and menstrual periods. Gross.

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7
Q

Recommended Iron intake per day?

A

Males: 10mg/day
Females: 18mg/day

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8
Q

How much iron do we absorb per day?

A

About 1 mg.

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9
Q

What does Iron do?

A

Oxygen carriers: Hemoglobin
Oxygen storage: Myoglobin
Energy Production: Cytochromes, krebs enzymes
Liver detoxification

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10
Q

Hemochromatosis

A

Iron overload.
Can take years to build up
Hemosiderin: extra iron in ferritin
Possibly related to cancers, cardiac toxicity.

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11
Q

Iron overload symptoms

A

Same symptoms as iron deficiency.
Being tired all the time
Lack of menstrual period

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12
Q

Blood tests for iron

A

Serum iron
TIBC - Total iron binding capacity
Transferrin saturation

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13
Q

Total average iron in adult male body

A

35 - 45 mg/kg or approximately 4g total

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14
Q

Distribution of Iron

A 
Red cell mass:  50%
Muscles as myoglobin:  7%
Storage as ferritin:  30%  mostly in liver
Other heme proteins:  5%
In serum:  0.1%
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15
Q

Where is transferrin made?

A

In the liver.
Transports iron between body locations
Iron taken up into cells by transferrin receptors

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16
Q

How many molecules can each transferrin bind?

A

Two Fe3 molecules.

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17
Q

In iron overload, what happens to transferrin production?

A

Production is decreased in iron overload, and increased in iron deficiency.

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18
Q

Serum transferrin + Serum Iron =

A

Transferrin saturation.

95% of serum iron is bound to transferrin.

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19
Q

How many iron molecules can a Ferritin bind?

A

4,500 atoms.

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20
Q

What is ferritin’s role?

A

Stores iron and releases it in a controlled fashion.

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21
Q

Reasons for iron loss?

A

Cell Loss (gut, desquamation)
Menstruation
Pregnancy, lactation
Bleeding (trauma)

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22
Q

Iron scavenging

A

Free hemoglobin –> hemopexin —> liver
Free heme –> Hemopexin —> liver
Heme passing through kidney is reabsorbed

23
Q

Where is iron absorbed?

A

Duodenum

24
Q

Only ___% of dietary iron is absorbed.

A

10%

25
Q

Hepcidin

A

Synthesized in the liver
Hepatic Bacteriocidal Protein.
Stops iron from getting out of gut cells —> makes it shed and be lost into stool.
Increases Iron loss in the gut

26
Q

Decreased Hepcidin production leads to?

A

Iron retention. Caused by low iron levels, low hemoglobin, low oxygen content.

27
Q

Increased Hepcidin Production

A

Increased Iron Loss. Caused by systemic inflammation (too much iron)

28
Q

Ferroportin

A

Present on the surface of cells to release iron into circulation. Gut cells, liver cells and macrophages.
Requires cofactor to oxidize iron to allow for binding to transferrin.
- Hephestin in gut
- Ceruloplasmin in other cells

29
Q

Iron deficiency

A
  • Extremely common. due to decreased intake, increased demands and increased loss.
  • Stores reduced before deficiency is seen.
30
Q

Is “Iron Deficiency” an adequate diagnosis?

A

No, the cause must be identified.

31
Q

Vitamin B12 (Cobalamin)

A
  • Plays a key role in normal functioning of the brain and nervous system.
  • Formation of blood
  • DNA synthesis and regulation
  • Obtained from diet, and produced by bacteria, stored in liver.
32
Q

T or F: B12 is fat-soluble.

A

False. B12 is water soluble. Get your shit in order.

33
Q

B12 plays a role in the recycling of ______? What do ______ do?

A

They play a role in recycling of folates.

  • Support RBC production
  • Help prevent homocysteine build up in blood
  • High levels of Homocysteine leads to inflammatory and coronary heart disease.
34
Q

B12 plays a role in methionine synthesis. What does methionine do?

A

It is an essential amino acid.
Comes from meat, fish and dairy products.
May treat depression, liver disease, inflammation and muscle pains.

35
Q

______ and ______ deficiencies show the same symptoms.

A

Vitamin B12 and Folate

36
Q

Megaloblastic Anemia

A

A vitamin B12 or Folate deficiency.
Anemia with larger than normal RBC’s.
Hypersegmented Neutrophils on CBC

37
Q

Neurologic Disorder

A

Probably secondary deficiency of methionine.
Deprivation of the nerves
Parasthesias

38
Q

Homocystenuria

A

Kyphosis
Lens subluxation
Atherosclerosis

39
Q

B12 and Folate must be given ______.

A

Together. Just giving one along may aggravate the disease.

40
Q

2 phases of B12 absorption

A

Gastric: Intrinsic factor binds B12
Intestinal: IF-B12 is absorbed in illeum

41
Q

Which deficiency is most commonly seen with B12 deficiency?

A 
Pernicious anemia (a form of megaloblastic anemia)
Failure to secrete intrinsic factor
42
Q

Folate (Folic acid)

A

Vitamin B9. Related to B12, need a good balance between folate and B12.

43
Q

Folate deficiency

A

Hyperhomocysteiemia: A risk factor for CVD.

Megaloblastic anemia

44
Q

Causes of folate deficiency

A

Inadequate intake
Impaired metabolism/absorption
Increased demand (pregnancy/lactation)
Elderly (poor diet/absorption)

45
Q

Medications that cause folate deficiency

A

Omeprazole (used for gerd)
OTC H2 blockers (Tagamet)
- reduce absorption or iron, folate, B12

46
Q

Microcytes

A

Drastically smaller RBC’s indicative or iron deficiency.

47
Q

Macrocytes

A

Larger RBC’s indicative of megaloblastic anemias and aplastic anemias.

48
Q

Polychromasia

A

Young RBC’s seen in severe anemia

49
Q

Basophilic Stippling

A

Pernicious anemia, seen in alcoholics and lead poisoning.

50
Q

Hypochromasia

A

Cells have decreased hemoglobin content, central pallor. indicative of iron deficiency anemia.

51
Q

Spherocytes

A

Hemolytic anemia

52
Q

Target cells

A

Chronic liver disease

53
Q

Helmet cells (Schistocyte)

A

Fragment of cell. indicative of hemolytic anemia or acute leukemia.

54
Q

Burr cells

A

Hemolytic anemias, iron deficiencies, or acute blood loss.

Hematology (14 decks)

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