Exam 3 Flashcards by Tommes Saatvedt

(___) iron is primarily from (___) sources while (___) iron is from mostly (___) sources

Heme, Animal, non-heme, plant

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What is heme iron derived from?

Hemoglobin and myoglobin. It must first be removed from the porphyrin ring structure via hydrolysis (proteases)

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How is heme absorbed across the brush border?

With the help of heme carrier protein (HCP1) and PCFT.

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In the (___) the heme porphyrin ring is hydrolyzed by (___) into (___) iron and protoporphyrin

enterocyte
heme oxygenase
ferrous

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Non-heme iron in the stomach is released with the help of (___) and (___) into its (___) form

HCl
proteases
Fe3+ (with some Fe2+)**
**3+ = ferric iron

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Three enzymes to reduce ferric iron at the brush border

cytochrome b reductase 1
Ferric cupric reductase
STEAP 2

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DMT1 can transport which minerals?

Zn, Mn, Cu, Ni, and Pb

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What happens to DMT1 when iron stores are high

more is synthesized, and less when iron stores are low

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go back for inhibitors and enhancers

xxx

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Without this mineral, Iron cannot beoxidized to the ferrix state and transported out of the liver.

Copper

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primary regulator of iron

hepcidin, released when stores of iron are adequate or high

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Iron sensor of the body

HFe-TfR2 complex (transferrin receptor 2)

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cornerstone of internal iron circuit

ferroportin

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ferroportin function

export iron into the plasma from the duodenum (absorption control)

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These two cells control the release of iron recovered from red blood cell catabolism and from stores.

Macrophages and hepatocytes

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Iron overload storage form

hemosiderin

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Three main sites for iron storage

liver, spleen, and bone marrow

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Cofactor for monooxygenases, dioxygenases, peroxidases, and oxireductases

Iron

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Vitamin C and Iron

C releases ferric iron from ferritin and reduces iron to the ferrous form

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Copper and Iron

Cu deficiency causes Fe deficiency. Cu is needed for the ferroxidase activity of hephaestin and ceruloplasmin

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Zinc and Iron

Zinc inhibits iron absorption and v/v minerals ingested together at a 2:1 ratio favoring non-heme iron

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Vitamin A and Iron

low A causes increased Fe accumulation in the spleen and liver; also altered RBC morphology

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Lead and iron

Lead reduces heme synthesis, associated with iron deficiency anemia

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Stages of iron deficiency

1) iron stores being to srop (plasma ferritin as index of depletion)
2) Iron stores depleted
3) plasma iron declines and iron available to bone marrow for hemoglobing drops
4) Anemia, rbc synth drops

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ZIP 4

Zinc carrier to cross brush border membrane into cytosol. Degraded by high Zinc intake

Acrodermatitis enteropathica

caused by a ZIP 4 mutation | characterized by poor absorption and skin lesions

Minerals that can absorb by diffusion

Zinc

transport of zinc in the blood is mostly handled by...

albumin

Stored zinc is bound to...

thionein as metallothionein

Stored zinc from these locations is poorly organized, even when intake is low

liver, kidneys, muscle, skin, and bones.

When zinc is low what happens to plasma zinc?

when intake is low, the less crucial plasma zinc enzymes and mettalothionein can be catabolized for ionic zinc

Vitamin A and Zinc

zinc is important in making RBC's which are needed to transport retinol. Without retinol, night blindness can occur.

Copper and Zinc

Zinc toxicity can induce Cu deficiency

Calcium and Zinc

compete for common absorption sites

Cadmium and Zinc

if Cadmium is high it prevents Zinc from binding to regular sites

Cu1+

cuprous

Fe2+

ferric

Cu2+

cupric

Fe3+

ferrous

Most food Cu is the (___) form

cupric 2+

Primary supplemental form of Cu

copper sulfate

Most Cu absorption happens in the (___) form

cuprous 1+

Copper transporters

Ctr 1 and DMT (which co-transports with H+)

ATP7B

moves Cu 1+ to the golgi network where it is incorporated into the ceruloplasmin

Cu is stored in (___) in the (___)

Mettalothionein, liver

Wilson's Disease

mutation of ATP7B where it is either absent or dysfunctional. This disrupts Cu excretion into the bile and then into the ceruloplasmin. Copper builds up in the liver

ergocalciferol

cholecalciferol; typical supplemented form, also synthesized by skin.

D synthesized in the skin goes to...

the blood bound to DBP

D from the diet is...

incorporated into the chylomicrons, enters the lymphatic system, and then enters the blood

D in the blood goes to

the liver

D in the liver

Converted to calcidiol (much of which is released into the blood).

What picks up most of the calcidiol from the blood and why

the kidneys when triggered by PTH

Calcidiol is hydroxylated to the active form (___) which is regulated by (___) and (___)

calcitriol FGF PTH

Rickets

vitamin D deficiency

Regulation of calcium is handled by three hormones

calcitriol PTH calcitonin

In response to low plasma Ca, (___) is excreted

PTH

In the intestine, (___) reacts with vitamin d receptors to induce transcription to code for (___)

Calcitriol | calbindin

Role of calcitonin in Ca regulation

lower serum Ca when the levels are high

Sodium levels

- Low: 140 mg or less per serving - Very Low: 35mg or less - Sodium Free: Less than 5mg per serving

Serum sodium maintained by

``` ADH aldosterone atrial natriuretic hormone renin angiotensin ```

membrane potential

concentration differences between K+ and Na+ across cell membranes to create an electrochemical gradient

Magnesium absorption is enhanced by

vitamin D and carbohydrates, D is not essential

Phosphorous absorption is increased by

PTH

High phosphorous stimulates (___) to suppress (___). doing so decreases the serum concentration of (___)

FGF23 Calcitriol Calcium

Three parts responsible for ECF volume and osmolarity maintenance

Hypothalamus Renin-angtiotensis-aldosterone system kidneys

Angiotensis II triggers the adrenal cortex to release (___) which tells the kidneys to excrete (___) and retain (___).

aldosterone K Na

Vasopressin is released by (___) in response to (___) and tells the (___) to retain more water

the hypothalamus angiotensin II kidneys

Responsible for tissue growth, cell-mediated immunity, assistance in insulin function and conversion of retinol to reinaldehyde

Zinc

Ceruloplasmin, superoxide dismutase, cytochrome c oxidase and others, tyrosine metabolism, nerve and immune function

Copper

Calcium metabolism and enhanced absorption, cell differentiation, bone development

Vitamin D

Enhance Ca absorption from guts and retention from kidneys, cause Ca bone mobilization

Calcitriol

Skeleton and blood clot formation, nerve transmission, muscle contraction

Calcium

Glucose co-transport, fluid balance maintenance, nerve transmission, muscle contraction

Sodium

Maintain electrolyte and pH balance, decrease Ca excretion, nerve tissue

Potassium

Bone structure, glycolysis, kreb cycle

Magnesium

Bone mineralization, DNA / RNA component, energy storage and transfer

Phosphorous