Sunday, April 15, 2012

Stars and human iron metabolism

Stars produce iron.

We need iron.

We REALLY need iron.

So there is a deep connection between the stars up in heaven and our existence as living beings. Without the iron they make, we would die. Interestingly, it is also highly toxic stuff. So our Creator has to be very accurate when using it!

Human iron metabolism is the set of chemical reactions maintaining human homeostasis of iron. Iron is an essential element for most life on Earth, including human beings. The control of this necessary but potentially toxic substance is an important part of many aspects of human health and disease. Hematologists have been especially interested in the system of iron metabolism because iron is essential to red blood cells. Most of the human body's iron is contained in red blood cells. Iron deficiency anemia is the most common type of anemia.

Understanding this system is also important for understanding diseases of iron overload, like hemochromatosis.

Iron is an absolute requirement for most forms of life, including humans and most bacterial species, because plants and animals all use iron; hence, iron can be found in a wide variety of food sources.

Iron is essential to life because of its unusual flexibility to serve as both an electron donor and acceptor.

Structure of Heme b; 
"Fe" is the chemical symbol of iron, 
"II" indicates its oxidation state.

The most important group of iron-binding proteins contain the heme molecules, all of which contain iron at their centers. Humans and most bacteria use variants of heme to carry out redox reactions and electron transport processes. These reactions and processes are required for oxidative phosphorylation. That process is the principal source of energy for human cells; without it, most types of cells would die.

The iron-sulfur proteins are another important group of iron-containing proteins. Some of these proteins are also essential parts of oxidative phosphorylation.

Humans also use iron in the hemoglobin of red blood cells, in order to transport oxygen from the lungs to the tissues and to transport carbon dioxide back to the lungs. Iron is also an essential component of myoglobin to store and diffuse oxygen in muscle cells.

The human body needs iron for oxygen transport. That oxygen is required for the production and survival of all cells in our bodies.

Human bodies tightly regulate iron absorption and recycling.

Iron is such an essential element of human life, in fact, that humans have no physiologic regulatory mechanism for excreting iron. Most humans prevent iron overload solely by regulating iron absorption. Those who cannot regulate absorption well enough get disorders of iron overload. In these diseases, the toxicity of iron starts overwhelming the body's ability to bind and store it.

Originally star dust ... then dust from earth ... but in great order and with deep wisdom and sub-milligram accuracy God has made us of dust, including some absolutely essential iron originating from the burning star factories in deep space.

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