Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

NHM 561 > Iron Part II > Flashcards

Iron Part II Flashcards

(50 cards)

Start Studying
1
Q

Iron is present as a part of heme in which 3 heme proteins?

A
  1. Hemoglobin
  2. Myoglobin
  3. Cytochromes (located in ETC)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

(TRUE/FALSE)

In hemoglobin/myoglobin, iron can form a loose bond with oxygen.

A

TRUE.

Hemoglobin will directly bind to oxygen, allowing us to transport it from the lungs to the peripheral tissue

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

What does hemoglobin do?

A

Allows oxygen transport from the lungs to tissue

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

What does myoglobin do?

A

Allows for the transitional storage of oxygen in muscle

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

What do cytochromes do?

A

Allows for the transport of electrons through the respiratory chain, which is important for us to generate ATP

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

Where is hemoglobin synthesized?

A

in RBCs

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

What % of total oxygen is found in blood?

A

~98.5%

RBCs also pick-up CO2 from the tissue and transport the CO2 to the lungs to be exhaled

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

How many hemoglobin molecules do a RBC contain?

A

Millions of hemoglobin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How much of our total body iron is stored in RBCs?

A

~65%

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

What is the structure of hemoglobin?

A

4 heme & 4 globin chains

These form 2 dimers and the molecule itself is referred to as a quaternary structure

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

What is the structure of myoglobin?

A

Single heme & single globin chain

(therefore, the oxygen capacity is greatly diminished because there is only one chain and it can only bind 1 molecule of oxygen)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Where is myoglobin found?

A

Present ONLY in muscles (heart & skeletal muscle)

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

How much of our total body iron is found in myoglobin?

A

~10%

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

What is the function of myoglobin?

A

Transports and stores oxygen within muscles and releases O2 to meet increased metabolic needs during muscle contraction

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

Where are cytochromes located?

A

within the membrane of the ETC

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

What is the function of cytochromes?

A

Cytochrome b and c pass along single electrons

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

Cytochrome P450 of enzymes

A

Functions in a similar manner within the liver, which requires iron to function

It is involved in drug metabolism and steroid hormone synthesis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are some iron-containing enzymes?

A

These enzymes require iron for the reactions to occur

NADH dehydrogenase
Succinate dehydrogenase
Monooxygenases
Dioxygenases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Who is at the greatest risk for iron deficiency?

A

Older infants
Young children
Women of child bearing age

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How many people worldwide have iron deficiency?

A

2 to 5 billion

~700 million with iron deficiency anemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

In developing countries, XXXXX of all children and women of childbearing age suffer from iron deficiency anemia, versus the US?

Study These Flashcards
A

1/3 in developing countries

9% of children between 1-2 y/o
12% pregnant women
11% females 16-49 y/o

21
Q

Define iron deficiency.

Study These Flashcards
A

DEPLETED STORES without regard to the degree of depletion or to the presence of anemia

Individuals can be iron deficient, without being anemic

22
Q

Define iron deficiency anemia.

Study These Flashcards
A

SEVERE DEPLETION of iron stores that result in a LOW HEMOGLOBIN CONCENTRATION

RBCs are pale, microcytic, and cannot carry enough oxygen to the tissues

23
Q

Explain clinical characteristics of IRON OVERLOAD.

Study These Flashcards
A

Occurs a lot with children, who have taken MVIs w/ iron in high doses.

HIGH FERRITIN
VERY HIGH TRANSFERRIN SATURATION
ALL other variables are normal

24
Explain the clinical characteristics of NORMAL IRON STATUS.
All normal
25
Explain the clinical characteristics of DEPLETED IRON STORES.
FIRST STAGE of iron deficiency occurs very early on, such that maybe dietary intake has declined significantly and recently. DECREASED FERRITIN DECREASED HEMOSIDERIN
26
What is the compensatory response for depleted iron stores (first stage)?
An increase in iron absorption that often prevents progression to more severe stages of iron deficiency. This stage is NOT associated with adverse physiological consequences, but does represent increased vulnerability from a long-term marginal iron balance, that might progress to a more severe deficiency.
27
What is the earliest indicator of iron status?
[FERRITIN] All other values remain NORMAL because remember- we have iron stores (intercellular ferritin and hemosiderin) which we store within our cells so this will keep the other markers in the normal range temporarily.
28
Explain the clinical consequences of a DECREASE IN TRANSPORT IRON (2nd stage).
SECOND STAGE of iron deficiency DECREASE [FERRITIN] DECREASE TRANSFERRIN SATURATION INCREASE ERYTHROCYTE PROTOPORPHYRIN (As the RBCs will take this protoporphyrin and use it to synthesize heme, this increases because there is NOT enough iron to make the heme, so this PRECURSOR will back up) NORMAL MCV NORMAL HEMOGLOBIN (so the individual is not experiencing any severe symptoms at this point)
29
Explain the clinical characteristics of IRON DEFICIENCY ANEMIA (3rd stage).
Characterized by decreased functional iron (decreased levels of HB) BIG DECREASE IN [FERRITIN] DECREASE IN TRANSFERRIN SATURATION BIG INCREASE IN ERYTHROCYTE PROTOPORPHYRIN DECREASE IN MCV DECREASE IN HEMOGLOBIN**'
29
Explain the clinical characteristics of IRON DEFICIENCY ANEMIA (3rd stage).
Characterized by decreased functional iron (decreased levels of HB) BIG DECREASE IN [FERRITIN] DECREASE IN TRANSFERRIN SATURATION BIG INCREASE IN ERYTHROCYTE PROTOPORHINE
30
What hemoglobin level would indicate severe iron deficiency anema?
Hemoglobin less than 70 g/L (<7 g/dL)
31
In the US, why are most cases of iron deficiency anemia among children and women mild?
Due to better access to healthcare compared to developing countries, which may result in it progressing further to a severe case.
32
Why are children greater than 6 months of age and young children at higher risk for iron deficiency?
Depletion of iron stores (d/t growth spurts) The low iron content of most infant diet Early feeding of cow's milk can promote increased GI blood loss
33
What 2 factors predispose women to iron deficiency anemia?
1. Menorrhagia (> 80 ml/month menstruation) 2. Pregnancy
34
Why does pregnancy predispose women to iron deficiency anemia?
1. Increase iron requirements to supply the expanding blood volume of the mother and the rapidly growing fetus and placenta 2. The total iron required during pregnancy averages 1g, thus exceeding the amount of storage iron available to most women (~0.3 g).
35
(TRUE/FALSE) Infant formula in the US is fortified with iron
TRUE
36
What causes iron deficiency anemia in the ELDERLY?
More commonly associated with chronic inflammatory conditions, such as arthritis
37
(TRUE/FALSE) GI blood loss may occur without notice and it can be from chronic use of drugs (aspirin) or lesions or tumors.
TRUE Iron deficiency anemia can result from GI blood loss, irrelevant of their iron dietary intakes
38
Explain the process of chronic inflammatory conditions and iron deficiency anemia in the elderly.
This is partly a protective mechanism. The response to chronic inflammation will be that HEPHAESTIN (hormone) will be released in large amounts from the liver. There has been a lot of data accumulated over the years that high iron in the blood can be used by microorganisms (for growth), so resulting in an increased risk for infections. So, one way the body shuts this down is that it will down-regulate the body's ability to absorb iron via the HEPAHESTIN hormone. HEPHAESTIN will go to the basolateral membrane (remember- its job is to block ferroportin) preventing iron from being pumped from the enterocyte across to where it can attach to transferrin.
39
In children, when do impaired mental development, reduced attention, and poor learning performance happen?
When HEMOGLOBIN levels are lower than 10 g/dL at 5 years of age
40
In adults, when does the substantial reduction in WORK CAPACITY occur?
When HEMOGLOBIN concentration falls below 100 g/L (10 g/dL) Impaired psychomotor development, intellectual performance, and changes in behavior can result as well. This is due to a decrease in oxygen perfusion to the brain and some of the CNS
41
(TRUE/FALSE) Even a mild degree of anemia can decrease performance during brief but intense exercise.
TRUE Due to that reduced oxygen perfusion to the tissue
42
What is the best treatment for iron deficiency?
FERROUS SULFATE is the least expensive and most widely used form of oral supplementation Recommended dose: 60 mg elemental iron per day for adults For: 2-3 months until iron levels are restored and indicators are WNL
43
How long does it take after treatment to see a response?
After 1 month, when the deficiency in hemoglobin is partially corrected, usually with a rise > 100 g/L. Iron treatment is continued for another 2-3 months.
44
Why is acute toxicity or iron poisoning, a concern?
Can lead to severe organ damage and death within hours or days Occurs mainly among young children Remember: Iron is VERY REACTIVE and PRO-OXIDATIVE, if it is NOT bound up to a protein and chaperoned throughout the body.
45
Define iron overload.
Nonspecific term for increased total body iron content with or without organ damage
46
Define hemosiderosis.
Results from increased iron stores in the form of hemosiderin
47
Define hemochromatosis.
Excessive storage of iron that causes organ damage; A genetic defect resulting in the inability of the intestinal cells to accurately sense iron stores, resulting in high iron absorption Caucasian males
48
What plasma ferritin concentration would indicate iron deficiency?
Less than 12 ng/mL

NHM 561 (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions