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Metabolism > Haemopoiesis, Iron > Flashcards

Haemopoiesis, Iron Flashcards

(51 cards)

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1
Q

Where does haemopoiesis occur ?

A

Bone marrow
Throughout skeleton in infant
Centrally located in adult (perlvis,sternum,skull,ribs…)

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2
Q

Where do we take trephine biopsy from ?

A

Left posterior iliac crest

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3
Q

What is the origin of haematopoietic cells ?

A

Multipotent haematopoietic stem cell

aka Haemocytoblast

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4
Q

What are the precursors of the haemopoietic cell lines ? which cells do they give ?

A
  • Common myeloid progenitor , gives Erythrocyte, Megakaryocyte,Myeloblast (Granulocytes)
  • Common lymphoid progenitor , gives LB and LT
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5
Q

Which hormone stimulate the production of RBC; Platelets,granulocytes and lymphocytes ?

A
  • RBC : EPO
  • Platelets : Thrombopoietin
  • Granulocytes : GM-CSF
  • Lymphocytes : IL , TNFs
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6
Q

What is the RES ? function ?

A

Reticuloendothelial system
A network in blood and tissues which is part of the immune system containing phagocytic cells
Role is to control and remove damaged/old blood cells

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7
Q

What are the main organs of the RES ?

A

Spleen , liver

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8
Q

Which cells are part of the RES ?

A

Scavenger cells :

macrophage/monocyte/Kupffer cells / histiocytes/Microglial cells in CNS

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9
Q

Normal range of haemoglobin ?

A

130-180 g/L

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10
Q

Normal RBC count ?

A

4.5-6.5 x10^12 /L

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11
Q

Normal Mean Cell Volume ?

A

80-100 fL

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12
Q

Normal WBC count ?

A

4-11 x10^9 /L

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13
Q

Platelet count ?

A

150-400 x 10^9 / L

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14
Q

When does the switch from foetal to adult haemoglobin occur ?

A

3-6 months old

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15
Q

In which state is the iron kept by the Haemoglobin ?

A

Ferrous (reduced)

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16
Q

What happens to the RBC components when broken down by RES ?

A
  • Iron recycled
  • Globin broken down in aa
  • Heme converted Biliverdin >Bilirubin>Liver bind to sugar >Bile>Stercobilin in faeces or Urobilinogen in urine
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17
Q

Describe the control of erythropoiesis in case of low pO2

A

Reduced pO2 detected in Peritubular cells in kidney > Increase EPO production > Stimulation of maturation and release of RBC from marrow > Haemoglobin rises > pO2 rises > EPO falls

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18
Q

What are the 2 main metabolic pathways occuring in the RBC ?

A

Glycolysis : main source of energy

Pentose phosphate pathway / generates NADPH

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19
Q

True or false : We can control how we absorb and excrete iron

A

Wrong , only how we absorb

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20
Q

What are the 4 forms of Available iron ?

A
  • Haemoglobin (2g)
  • Myoglobin
  • Tissue iron (cytochrome mitochondrion)
  • Transported : Serum iron (3mg)
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21
Q

What are the 2 forms of stored iron ?

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A

Ferritin: soluble
Haemosiderin: Insoluble , in Macrophages (brown)

22
Q

Approximatively how much iron is lost during a day ?

23
Q

Which iron is better ? why ?

Study These Flashcards
A

Haem iron, because Ferrous form and can enter enterocyte as is

24
Q

How is the non-haem ferric iron is transformed to ferrous ?

Study These Flashcards
A

Converted by gastric acid

25
How is iron absobed and where ?
- Binds to TRANSFERRIN | - Through apical surface in Duodenum and upper Jejunum
26
Which transporter is involved in iron absorption in intestins ?
DMT1 : divalent metal transporter
27
How is the iron exported from the enterocyte to blood ?
Ferroportin
28
Which transporter help absorb iron from milk ?
Lactoferrin
29
How is the iron taken up in cells from blood ?
Transferrin receptor (TfR) binds the Iron-transferrin complex
30
Which cell has the highest nbr of TfR ?
Erythroid cells
31
What food increases and reduces iron absorption ?
- Increases : Vit C , ascorbic acidic : orange juice | - Decreases: Tea, Chapatis,Antacids
32
How are the dietary iron levels sensed ?
By enterocytes' villi
33
What are the absorption control mechanisms ?
- Regulation of transporters - Expression of receptors (HFE, TfR) - Hepcidin and cytokines - Crosstalk between epithelial cells and macrophages ...
34
What is the function of Hepcidin ?
Negative regulator of iron absoprtion and release (macrophages)
35
When and where is hepcidin produced ?
Made in liver Excreted by the kidney When iron overload
36
How does hepcidin work ?
Binds to Ferroportin on Enterocyte and Macrophages and induce internalisation and degradation of ferroportin preventing absorption and release of iron in blood
37
what stimulate the rpoduction of hepcidin ?
HFE TfR Cytokines
38
What are the causes of iron deficiency ?
- Insuficcient intake/absorption | - Increased use : physio(pregnancy) or patho(bleeding)
39
What are the symptoms of iron deficiency ?
- tiredness - reduced oxygen carrying : Palor, cant exercise - Cardiac symptoms : angina,palpitations...
40
What are the signs of iron deficiency ?
``` Pallor Tachycardia Increased resp rate Epithelial changes (shiny tongue, around mouth) Koilonychia (concave nails) ```
41
What are the blood film features and blood parameters in iron deficiency ?
Hypochromic : low haemoglobin content Microcytic : small RBC and low MCV Anisopoikilocytosis : change in size and shape Pencils and target cells Low serum ferritin ,serum iron and transeferrin saturation Low reticulocyte haemoglobin content
42
Which test would you do to determine iron deficiency ?
``` Ferritin levels (reduced levels indicate iron deficiency) CHR only for functioning iron deficiency but not in thalassaemia ```
43
Why does raised or normal Ferritin levels do not exclude iron deficiency ?
Because it s an acute phase protein so raised if inflammation (acute or chronic), malignancy , liver disease and alcoholism
44
What is the treatment for iron deficiency ?
- Dietary advice - Iron tablet - Intramuscular injections - intravenous iron - transfusion only if sever anaemia
45
Why can free iron be dangerous ?
Can exceed Transferrin binding capacity Reduced iron (ferrous) can produce highly reactive HYDROXYL and LIPID RADICALS > Damage lipid membranes,nucleic acid,proteins Deposit in tissue
46
What is haemochromatosis ?
Disorder of iron excess resulting in end organ damage due to iron deposition
47
What are the consequences of haemochromatosis ?
- Liver cirrhosis - Diabetes mellitus - Hypogonadism - Cardiomyopathy - Arthropathy - Skin pigmentation
48
What is hereditary haemochromatosis due to and treatment ? and inheritance pattern ?
Mutation in HFE gene Autosomal recessive Too much iron enters cell Treat : venesection
49
What is the role of HFE protein ?
Binds to TfR and compete with Transferrin preventing uptake of Transferrin-Iron complex
50
State a haemochromatosis disease other than Hereditary H
Transfusion associated haemosiderosis in transfusion dependent patient (thalassaemia) Gradual accumulation
51
State an iron chelating agent
Desferriorxamine

Metabolism (6 decks)

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