Iron is an essential mineral that plays a crucial role in various biological processes, including oxygen transport, DNA synthesis, and energy production.

Iron Metabolism:

1. Absorption: Iron is primarily absorbed in the duodenum and upper jejunum. It exists in two forms in the diet: heme iron (found in animal products) and non-heme iron (found in plant and animal products). Heme iron is more readily absorbed (about 15-35%) compared to non-heme iron (about 2-20%).
2. Transport: Once absorbed, iron binds to transferrin, a plasma protein that transports iron throughout the body. Transferrin carries iron in its ferric (Fe^3+) form.
3. Storage: Iron is stored in the body mainly in the form of ferritin, primarily in the liver, spleen, and bone marrow. Ferritin is a protein that can store thousands of iron atoms in its core.
4. Utilization: Iron is utilized for various physiological functions, including the synthesis of hemoglobin in red blood cells (RBCs), myoglobin in muscles, and various enzymes involved in energy metabolism and DNA synthesis.
5. Recycling: Iron is recycled from senescent RBCs by macrophages in the reticuloendothelial system (mainly in the spleen and liver). Hemoglobin from these RBCs is broken down into heme and globin. Heme is further degraded into biliverdin (which is converted to bilirubin) and iron. The iron is then released and either stored in ferritin or transported back into circulation bound to transferrin.

Iron Transport:

1. From Diet to Bloodstream: Iron from the diet is absorbed in the duodenum and upper jejunum. It enters enterocytes (cells lining the intestines) through various transporters, including DMT1 (divalent metal transporter 1). Inside the enterocyte, iron can be stored as ferritin or transported across the basolateral membrane into the bloodstream. Ferroportin is the main transporter responsible for exporting iron out of enterocytes into the bloodstream.
2. From Macrophages to Bloodstream: Macrophages engulf senescent RBCs and break down hemoglobin into its components. Iron released from heme is either stored as ferritin or exported out of the macrophage via ferroportin. Once in the bloodstream, iron binds to transferrin for transport to various tissues and organs.
3. Regulation: Iron absorption and transport are tightly regulated to maintain iron homeostasis in the body. The hormone hepcidin plays a central role in this regulation by inhibiting ferroportin, thereby reducing iron absorption from the gut and iron release from macrophages when iron levels are high.

Understanding these processes is critical for managing conditions related to iron deficiency or overload, such as anemia or hemochromatosis.

Try to answer the question below (based on the video):

QUESTION: False about the mechanism of action of Hepcidin

A. Hepcidin inhibits ferroporitin

B. Hepcidin levels rise in iron deficiency anemia

C. Hepcidin levels can increase in acute and chronic inflammation

B. Hepcidin regulates iron levels by blocking basolateral iron uptake