Human iron metabolism in the context of "Iron deficiency"

The spleen (from Anglo-Norman espleen, ult. from Ancient Greek σπλήν, splḗn) is an organ found in almost all vertebrates. Similar in structure to a large lymph node, it acts primarily as a blood filter.

The spleen plays important roles in regard to red blood cells (erythrocytes) and the immune system. It removes old red blood cells and holds a reserve of blood, which can be valuable in case of hemorrhagic shock, and also recycles iron. As a part of the mononuclear phagocyte system, it metabolizes hemoglobin removed from senescent red blood cells. The spleen is a center of activity of the mononuclear phagocyte system and is analogous to a large lymph node, as its absence causes a predisposition to certain infections. The globin portion of hemoglobin is degraded to its constitutive amino acids, and the heme portion is metabolized to bilirubin, which is removed in the liver.

Hereditary haemochromatosis type 1 (HFE-related haemochromatosis) is a genetic disorder characterized by excessive intestinal absorption of dietary iron, resulting in a pathological increase in total body iron stores. Humans, like most animals, have no mechanism to regulate excess iron, simply losing a limited amount through various means like sweating or menstruating.

Excess iron accumulates in tissues and organs, disrupting their normal function. The most susceptible organs include the liver, heart, pancreas, skin, joints, gonads, thyroid and pituitary gland; patients can present with cirrhosis, polyarthropathy, hypogonadism, heart failure, or diabetes.