Iron and Heme Metabolism

[Overview] RBCs are rich in

Heme

[Overview] Can also be found in the liver, muscle cells in the form of

non-heme proteins

[Overview] RBC plays a role in ___ transport

gas

[Overview] RBC uses _____ which have a prosthetic group called the _____.

Hemoglobin; heme group

[Overview] the ultimate molecule responsible for the binding and unbinding of oxygen

Heme group

[Overview] This enables the transport of oxygen

Heme group

[Overview] Heme group is composed of ______

a metal complex (Iron) and porphyrin ring

[Overview] Once the RBC has served its purpose, it will liberate the

hemoglobin/heme group

[Overview] The hemoglobin/heme group will be catabolized to ____

two (Ten) reactions to create bilirubin

[Overview] The metal complex of Heme is ____

Iron

[Heme Complex] Iron is an____ metal

essential transition

[Heme Complex] What are essential nutrients?

nutrients that the body cannot produce in sufficient quantities on its own, even if they are necessary for good health.

[Heme Complex] What are the 4 physiological functions of Iron?

Oxygen transportEnergy metabolismCell proliferation Immune System

[Heme Complex] What physiological functions of Iron is being described? acts as a cofactor especially for oxidative phosphorylation

Energy metabolism

[Heme Complex] What physiological functions of Iron is being described? also used by microorganisms in proliferation

Cell proliferation

[Heme Complex] What physiological functions of Iron is being described? Cytochrome P450 enzymes help to detoxify foreign substances, while lysosomal enzymes, such as myeloperoxidase, are involved in the killing of pathogens.

Immune System

[Heme Complex] The recommended daily amount (RDA) of Iron for men and post-menopausal women is:

8-10 mg for men and postmenopausal women

[Heme Complex] The recommended daily amount (RDA) of Iron for pre-menopausal women is:

15 mg for pre-menoposal

[Heme Complex] The recommended daily amount (RDA) of Iron for pregnant women is:

30 mg for pregnant women

[Heme Complex] Why is the iron RDA higher for pre-monoposal and pregnant women

Women have more iron in their body probably due to menstrual blood loss; Due to the creation of RBCs of the mother and the fetus

[Heme Complex] Iron is not only used in heme proteins, it is also used in ___

energy metabolism and heme immune defense

[Heme Complex] Iron bound to heme is usually used in ____ transport

oxygen

[Heme Complex] Free iron in the blood is considered _____ and may cause ______ through _____ reactions

cytotoxic; May cause peroxidation through your fenton reaction

[Heme Complex] Cell injury produces H2O2 and interaction with Iron leads to the formation of highly reactive _____

hydroxyl radicals.

[Heme Complex] Loss of Iron in the body is perpetuated by 3 processes:

Sloughed Mucosal cells and Desquamation Menstruation Miscellaneous Blood loss (1-2 mg per day)

[Iron Distribution] Most of iron exists in heme but can exist in 2 major different forms

Functional (75%) Used for oxygen transport Non-Functional (25%) Used for iron transport or storage inside the cell

[Iron Distribution] transports oxygen

Hemoglobin

[Iron Distribution] used for respiratory chain or redox reaction and is also used in photosynthesis

Iron–sulfur clusters and Iron containing enzymes

[Iron Distribution] Functional iron subtypes are:

HemoglobinMyoglobinIron–sulfur clusters and Iron containing enzymes

[Iron Distribution] Used for iron transport or storage inside the cell

Non-Functional (25%)

[Iron Distribution] is stored iron derived from excess iron binding to apoferretin

Ferritin

[Iron Distribution] Empty ferritin shell without iron

Apoferritin

[Iron Distribution] In the_____, kupffer cells take up old RBCs using phagocytosis and store their iron in ferritin

Liver sinusoids

[Iron Distribution] In the Liver sinusoids, kupffer cells take up old RBCs using ______ and store their iron in ferritin

phagocytosis

[Iron Distribution] In the Liver sinusoids, ____ take up old RBCs using phagocytosis and store their iron in ferritin

kupffer cells

[Iron Distribution] are specialized macrophages found in the liver

Kupffer cells

[Iron Distribution] Iron is mostly stored by ____

the macrophages formed in the spleen and the bone marrow

[Iron Distribution] is a ferritin derivative that stores iron in the liver

Hemosiderin

[Iron Distribution] Hemosiderin can be observed with ___ stain

prussian blue

[Iron Distribution] ____ are temporary stored forms of iron in the reticulo-endothelial system

Microphages

[Iron Distribution] Transfers the iron in the blood so it could go into the bone barrow for eretropoeisis

Transferrin

[Iron Distribution] Transferrin transfers the iron in the blood so it could go into the _______

bone marrow for eretropoeisis

[Iron Distribution] Gives iron to muscles to incorporate it to the heme

Transferrin

[Iron Absorption] Iron is absorbed in the

proximal duodenum and the upper jejunum

[Iron Absorption] The absorption of iron depends on the

nature of the iron or the oxidation of iron

[Iron Absorption] A more ___ environment is better for iron absorption

acidic

[Iron Absorption] Iron enters the body through the form of ___

dietary iron

[Iron Absorption] Iron in the form of ___ is readily absorbed from __ sources compared to plants

heme; meat

[Iron Absorption] Enterocytes have transporters for __ , _ has to be converted

ferrous irons only, ferric iron

[Iron Absorption] ___ also known as ___ has the ability to reduce Fe3+ to Fe2+

Duodenum cytochrome B; Ferrireductase

[Iron Absorption] The ferrous iron enters the apical side of the enterocyte using ____

DMT1 (divalent metal transporter)

[Iron Absorption] There are two fates after entering the eneterocyte that depends on the ____

body's capacity to require or have enough of iron

[Iron Absorption] If the body needs more iron, it will exit through the basal-lateral site using __

Ferroportin 1

[Iron Absorption] If the body has enough, excess iron will be sequestered to the ____ in the enterocyte to prevent cellular toxicity

apoferritin

[Iron Absorption] If the body needs more iron, it will exit through the _____ site using Ferroportin 1

basal-lateral

[Iron Absorption] In the context that the body needs more iron: After exiting the enterocyte, we have to reconvert the Ferrous to Ferric because _____

Transferrins can only transport Ferric ions

[Iron Absorption] In the context that the body needs more iron: ______ oxidizes Ferrous to Ferric, allowing it to bind to transferrins and then circulate all over the blood stream

Hephastein (Ferroxidase)

[Iron Absorption] In the context that the body needs more iron: ____ will bind to Ferroportin later when the cell has enough iron

Hepcidin

[Iron Absorption] In the context that the body needs more iron: Using transferrin, ferric ions could proceed into the following organs:

LiverBileTissuesBone

[Iron Absorption] In the context that the body needs more iron: ferric ions could proceed into the Liver for

storage as ferritin or hemosiderin

[Iron Absorption] primary iron storage protein and can store larger amounts of iron

Ferritin

[Iron Absorption] forms when ferritin becomes overloaded and provides a more stable, but less readily accessible, form of iron storage.

Hemosiderin

[Iron Absorption] In the context that the body needs more iron: Ferric ions could proceed into the Bile for

digestion

[Iron Absorption] In the context that the body needs more iron: Ferric ions could proceed into the Tissues for

production of cytochrome, iron cofactored enzymes, and myoglobin

[Iron Absorption] In the context that the body needs more iron: Ferric ions could proceed into the Bone for

erythropoiesis (RBC production)

[Iron Absorption] Once they are near death, the old RBCs will be phagocytized by

Reticulo-Endothelial Cells

[Iron Absorption] can be used to detect iron levels in the body

Ferritin

[Iron Absorption] Iron is returned to the ____ to be used again

bloodstream

[Iron Absorption] Iron can be lost through the

Skin (Desquamation) Sweat Urine and Feces Blood Loss (Main) - Bleeding and Menstruation

[Iron Absorption] Differentiate Ferrous and Ferric Iron

Fe2+ aka FerrOUS = twO is the absorption foromFe3+ aka FeRRIc - thREE is the plasma transportation and storageFerIICOT sa katawan

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Phytates

Inhibitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Tannines

Inhibitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Soil Clay

Inhibitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Laundry Starch

Inhibitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Iron overload

Inhibitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Antacids

Inhibitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Lead

Competitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Cobalt

Competitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Strontium

Competitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Manganese

Competitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Zinc

Competitors

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Ascorbate

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Citrate

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Amino Acids

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Iron Deficiency

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Stomach Acid

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? High Altitude

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Exercise

Facilitators

[Iron Absorption] Is this an inhibitor, competitor, or facilitator of Iron absorption? Pregnancy

Facilitators

[Iron Absorption] How do competitors of iron absorption work?

Divalent Metals compete for the attention of DMT1

[Iron Regulation] How do competitors of iron absorption work?

Divalent Metals compete for the attention of DMT1

[Iron Regulation] the basis of iron homeostasis

Mucosal Block Theory

[Iron Regulation] There is a specific level of iron that will prevent further absorption by the ____

enterocytes

[Iron Regulation] Remember that Iron overload will cause the excess iron to be stored by ______ and will eventually be shed by ___, thus effectively disposing iron

apoferritin; desquamation in 1-2 days

[Iron Regulation] 25AA peptide that binds to ferroportin

Hepcidin

[Iron Regulation] Hepcidin binds to this transporter and degrades and internalizes it

ferroportin

[Iron Regulation] Hepsidin synthesis is regulated by

HFE (hemochromatosis protein) Transferrin receptor 2 Hemojuvelin - co-receptor for bone morphogenetic protein 6 (BMP6).

[Iron Regulation] A decrease in Hepcidin Synthesis increases or decreases iron levels?

Increases iron levels

[Iron Regulation] A increase in Hepcidin Synthesis increases or decreases iron levels?

Decreases iron levels

[Iron Regulation] Does this lead to an increase or decrease in hepcidin synthesis? Ineffective ertythropoiesus

Decrease in hepcidin synthesis/ Increases iron levels