iron Flashcards
1
Q
where is iron found
A
center of hemoglobin in ferrous 2+ state
2
Q
iron can REVERSIBLY bind with
A
oxygen
3
Q
heme binds with _________ in lungs and carries to tissues
A
oxygen
4
Q
oxidized iron in ferric state
A
methemoglobin (doesn’t carry oxygen)
5
Q
how much do humans have of iron (all forms)
A
3-5 grams
6
Q
how much iron is transported to bone marrow for heme molecules
A
80%
7
Q
if you can’t get iron
A
iron deficiency anemia (IDA)
8
Q
what is the center of myoglobin (muscles)
A
iron
9
Q
massive breakdown of muscle=
A
lots of free iron released (toxic to the body)
10
Q
iron storage places
A
bone marrow, liver, and spleen
11
Q
2 forms of iron storage
A
ferritin and hemosiderin
12
Q
how does iron get into RBC?
A
via transferrin receptors
13
Q
where does iron go
A
depending on the needs of the cell
-shuttle for storage
-mitochondria for hemoglobin
14
Q
how is iron regulated
A
absorption in intestine
15
Q
how can absorption be disrupted
A
gasteric bypass surgery
chrone’s disease
if lining of intestine disrupted- absorption disrupted
16
Q
what state of iron does absorption occur in
A
ferrous 2+
17
Q
what state is iron after absorption
A
ferric 3+ bu gut mucosa
18
Q
normal serum iron levels
A
60-170 mg/dL
19
Q
body iron distribution
A
1) functional iron– needed for metabolic processes
2) Transport iron finish
20
Q
body iron distribution
A
1) functional iron
2) transport iron
3) storage iron
21
Q
functional iron
A
needed for metabolic processes (ex. Hgb)
22
Q
transport iron
A
transferrin helps iron
-serves as way to get iron where needed
-prevents toxicity
-keeps iron soluble
23
Q
storage iron
A
ferritan– 800 mg in the body
24
Q
where is ferritin found
A
liver
spleen
bone marrow
macrophages
25
what moves to beta region on electrophoresis
transferrin
26
where is transferrin secreted?
apoferritin molecule (shell helps transport ferritan)
27
how many molecules of ferric iron does transferrin bind
2
28
what is the saturation rate of transferrin with iron
30%
29
in IDA saturation rate ____ because no iron to bind to
decreases
30
in IDA serum levels _______ because un bound transferrin
increased
31
what is saturation in iron overload
increased
32
in iron overload serum transferrin _______ because bound
decreased
33
main iron storage form
ferritan
34
most diagnostic indicator of IDA
ferritan
35
DO NOT look at serum iron as indicator of IDA because
serum levels remain normal because pulling from storage so look at ferritan
36
main iron storage site
liver
37
if there is liver damage
can't hang onto iron
-release ferritin
-increase in serum iron
38
end stage hepatitis = iron toxicity
liver lets go of iron and dumped everywhere
39
APR acute phase reactant
ferritin
40
how is ferritin an acute phase reactant
increased in inflammation, malignancy, infection
COVID people have increased ferritin levels
41
ferritin woman levels
10-120
42
men ferritin levels
20-250
43
2nd form of storage iron
hemosideran
44
how is hemosiderin released from the body
slowly
45
granules in liver and macrophage help diagnose with prussian blue stain
hemosiderin granules
46
anemia has decreased
iron granules
47
protein made only in liver
hepcidin
48
what is main iron regulatory hormone
hepcidin (nothing to do with iron)
changes of mutations lead to IDA or iron overload
49
where is hepcidin found
serum or urine
50
function of hepcidin
control amount of extracellular iron that gets into body
51
how does hepcidin regulate
1) decrease or increase dietary iron absorption
2) control amount of iron released, enterocytes, gut cells, and macrophages
3) either destroying or not destroying ferroportin
52
ferroportin channels
in order iron inside cells to outside goes through ferroportin tube to extracellular
53
hepcidin can break down ferro protein to
decrease release
54
iron deficient in serum:
hepcidin levels decrease because need fetoprotein tubes are needed
55
iron overload in serum:
hepcidin increases because break down ferroportin so iron can't exit
56
_______ follows iron levels
hepcidin
57
another APR
hepcidin
58
when hepcidin increased due to inflammation
will decrease serum iron levels
59
appear iron anemic but not
anemia of chronic inflammation
don't give more iron! need to decrease inflammation
60
all cells have _______ receptors on them
transferrin
(bind transferrin and iron complex)-- receptors turn inward release and turn back outward
61
once iron released
cleaved by enzymes and become soluble in serum
62
increase receptor
go along with decrease in available iron (wants every molecule it can find to attach to transferrin)
63
increase in iron= decrease in receptors
don't need to go out and looks for them, it comes to them
64
NOT APR
soluble transferrin receptors
advantage because won't increase in inflammation only in relation to iron status
65
look at chart in book
66
average iron balance in male
4 grams of body iron
67
average iron body woman
2.5 grams -- lower RBC count
68
daily requirement of iron depends on
age, infant, toddlers, puberty, gender
69
lose 2 mg of iron everyday through
stool
urine
cells - dying
70
where does iron regulation -- absorption occur
intestine
body uses what it needs and get rids of rest
71
major factors of iron abs
rate of RBC production
rate of myoglobin production
iron stored
72
what vitamin stored in combo with iron
vitamin C-- helps with absorption
alcohol also increases absorption
73
interfering sources of absorption
dairy foods
tea
iron and calcium taken at same time
certain antibiotics
74
leading cause of anemia
iron deficiency
75
#1 reason for IDA
nutrition
76
other reasons for IDA
-lead poisoning
-gastric bypass
-crohn's disease
-celiac disease
-parasitic infection
77
how does IDA develop
serum iron first lowered
don't see because call on ferritin to pull out reserve
-no symptoms until serum iron levels are low upon testing (ferritin also low)
78
test levels full blown IDA
decreased MCV, MCH, MCHC
increased transferrin, total binding iron capacity
decreased percent saturation
increased soluble transferrin receptors
decrease hepcidin-- no inflam.
79
what happens in body during IDA
-lack of energy(oxygen not getting around)
-decrease mental capacity in child
-decrease growth
-large tongues
-sores in mouth
impairment of GI tract
80
main reason for iron overload
MAIN: hereditary hemochromatosis
81
hereditary hemochromatosis
not everyone homozygous- show expression later in life
men 5x to display symptoms because aren't getting rid of iron like women
can absorb more iron than body needs
82
hereditary hemochromatosis symptoms
tan
liver problems
diabetes
83
if not dealt with how much iron can be in body
20 g
84
look at lab test for hereditary hemochromatosis
85
lots of patients get liver biopsy
prussian blue stain for hemosiderin
86
treatment for hereditary hemochromatosis
therapeutic phlebotomies
-chelation therapy
87
what occurs in celation therapy
deferoxamine
88
other reason for Iron overload
hemosiderosis
89
hemosiderosis
iron over load due to repeated blood transfusions
ex. sickle cell
have to monitor for diabetes, liver disease (pancreas destroyed bc iron overload)
use celation?
90
specimen for iron testing
serum tube and heparin
no oxalate, citrate, or EDTA : binds iron
91
combine detection ... color metric
dissociation ferric iron from transferrin through addition of acid
ferric-- ferrous= chromagin + ferrus = color proportional to amount of serum iron
92
serum iron levels
60-170
93
amount of iron that transferrin can bind if all binding sites saturated
TIBC
94
TIBC reflects
unsaturated transferrin (UIBC)
95
total iron binding capcity=
unsaturated iron binding capacity + serum iron
96
TIBC procedure?
1) saturate serum with per determined amount of iron that will saturate all transferrin sites
2) add agent that complex will all unbound iron
97
normal TIBC
250-425
98
amount of transferrin saturated with iron at any given moment
% saturation
99
% saturation equation
serum iron/ TIBC. x 100
100
normal % sat
20-50 %
below 20= IDA
above 50 = iron overload
101
