Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
25 Cards in this Set
- Front
- Back
|
Where is iron mainly absorbed?
|
Duodenum & upper jejunum
|
|
|
How much iron is absorbed a day?
|
1-2mg
|
|
|
What is most absorbed iron used for?
|
Erythropoiesis (in the bone marrow)
|
|
|
Iron is bound and trnsported in the body via ..... and stored in ...... molecules
|
transferrin
ferritin |
|
|
Haeme / non-haeme iron remains soluble during digestion
|
Haeme
|
|
|
How does Fe2 cross the enterocyte membrane?
|
via specific transporter HCP1
|
|
|
What facilitates non-haeme iron transfoer across intestinal epithelial cells?
|
devalent metal transporter 1 (DMT 1)
|
|
|
List some factors inhibiting iron absorption
|
high iron status, milk, phytates, oxalic acid, polyphenols, coffee, zinc, malabsorption, GIT blood loss
|
|
|
Lost some factors enhancing iron absorption
|
low iron status, erythropoiesis, meat, poultry, fish, alcohol, fructose, vit C,
|
|
|
Where does regulation of iron uptake occur?
|
basal membrane of intestinal mucosal cells
|
|
|
What is the name of the iron-binding protein
|
apoferritin
|
|
|
T/F iron can be stored in the liver
|
true
|
|
|
In the blood, ...... is reoxidised to ...... by ........ and carried by the serum protein .........
|
Fe2
Fe3 ferroxidase II transferrin |
|
|
What forms is iron stored in the liver in?
|
ferritin or haemosiderin
|
|
|
Describce why excess iron might be dangerous
|
If iron increases beyond normal levels, excess haemosiderin is deposited in the liver & heart, which can impair these organs
|
|
|
How is the body protected from the free radicals that iron may generate?
|
it is transported and stored bound to a protein (glycoprotein transferrin)
|
|
|
Explain how an unexpected influx of iron can be easily handled
|
because transferrin is normally only about 1/3 saturated with iron
|
|
|
What is the catalyst that oxidises Fe3 to Fe3?
|
Ceruloplasmin
|
|
|
T/F
Ceruloplasmin contains copper |
True
|
|
|
How does the body respond to absorption of excess dietary iron?
|
By producing more ferritin to facilitate iron storage
|
|
|
What are two examples of iron excess?
|
haemochromotosis and haemosiderosis
|
|
|
List 4 components that are required for release of iron from iron stores
|
riboflavin as FMNH2
niacin as NADH vitamin C or chelating agent copper in ceruloplasmin |
|
|
T/F
Iron is not very chemically active |
False
|
|
|
List 4 ways that iron is lost from the body
|
bleeding
sloughing of cells mestrual flow transfer to developing foetus |
|
|
What are the primary functions of iron
|
oxygen transport & storage
oxygen sensing energy metabolism antioxidant functions DNA synthesis |
