Maroon and shaped like a boomerang, the liver is the second largest organ in the body (the skin always steals this glory). The reason why it's so vital is that it serves as your body's border inspection station. Virtually every nutrient we consume, whether it has a valid passport or not, must pass through the liver so it can be transformed into a different biochemical form. That transformation is what allows the nutrient to be used, transported to a different location in the body, or stored as an extra inch of blubbery goop on your thighs.
Structurally speaking, here's what you need to know about the liver. It's located just below the right rib cage in the upper right side of the abdomen, above the pancreas and the small intestine. Your liver does three main things: helps digest stuff, make proteins, and gets rid of bad stuff.
All of the blood that has visited your small intestines flows through your portal vein into your liver, so almost all of the nutrients you eat have to pass through the gauntlet of the liver before passing to the heart for generalized distribution. Why "almost"?
There's a little absorption in your mouth and under your tongue, but almost means 99 percent for the typical person. Your liver decides what gets kept out, what gets patted down and inspected, and what's allowed in to be distributed throughout your body.
Within the organ, there's a network of bile ducts; bile, if you remember from the last chapter, is the greenish liquid produced in the liver that helps break down fats. The liver also uses bile to clear bilirubin from the blood. Biliwhat, you say? Bilirubin?it's a substance that comes from the breakup of hemoglobin in dead redblood cells. An increased level of bilirubin results in jaundice (a yellowing of the skin and all mucous membranes?that includes the eyeballs, where the yellowing is usually detected earliest and most easily), a sign of many liver diseases.
The various functions of the liver are carried out by the liver cells, called hepatocytes.
They are responsible for the organ's ability to regenerate; hepatocytes act as stem cells that can re-form liver tissue. These cells work primarily to serve these functions:
NUTRIENT BREAKDOWN We all may know that skim milk is good for your bones, fish is good for your muscles, and olive oil is good for your heart. But only a weird cartoonist thinks that your bones actually bathe in milk or there's a blood vessel that transports fresh olive oil through a side door in the aortic chamber.
Everything we eat and drink has to be broken down into different chemicals before it can get to work on helping (or, in the case of some foods and drinks, harming) your body. And that's one of the primary jobs of the liver.
STORAGE AND CREATION The liver, which makes protein and stores glucose, vitamin B12, and iron, helps get nutrients to your body by processing all foods? carbohydrates, protein, and fat?into glucose that can be used throughout your body. Glucose is a fancy name for a specific and common sugar (yup, everything is turned to sugar). Iron stores in the liver are great enough for most people that iron supplements are not usually needed, except in people with iron deficiency anemia, which is the most common nutritional deficiency worldwide. The liver also serves as the initial source of glucose when you rush the hot dog stand at halftime (even be-fore you get there), since the sugar in your blood provides only ten minutes of energy.
It then does double duty to break down the nitrates from that hot dog in the detox function described below. This, by the way, is the reason why you don't burn fat immediately when you start exercising?it's because your body is using the fuel that's stored as glucose in the liver first.