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Liver

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The liver is a multifunction organ. Has these jobs:

Part of the digestive system

Detoxification

Stores energy

Produces cholesterol

 

Produces bile to break down fats

Liver produces bile, a detergent that breaks up fat into small particles.

Bile is stored in the gallbladder, and released when you are digesting a meal.

Gallbladder Bile release GIF

 

Here we see bile salts emulsifying a globule of fat.

Bile as an Emulsifier Detergent fats

from pathwayz.org

Detoxification

“Almost all the blood in your body passes through the liver.”

Liver

US Dept of Veterans Affairs, Liver as Filter

“As blood passes through the liver, it breaks down substances, such as prescription or over-the-counter drugs, street drugs, alcohol, and caffeine.”

“Our bodies naturally produce some harmful (toxic) chemicals or poisons, and those are also broken down by the liver.”

“In this way the liver acts as a filter to clean your blood.”

 

Energy storage in glycogen

The liver takes excess sugars and links them together into a large molecule called glycogen.

Glycogen is stored until energy is needed.

glycogen glucose

Image from National 5 Biology, nat5biopl.edubuzz.org

Makes cholesterol

The liver makes cholesterol.

cholesterol

Contrary to popular belief, cholesterol is not bad for you: In fact, you’d instantly stop living if you didn’t have any in your body.  All cell membranes in animals have some cholesterol as part of their structure.  And many critical hormones are made by using cholesterol as a starting point.

Why do people think that cholesterol is bad? Over the last 200 years the American diet has changed. People now have vastly less whole foods, vegetables, whole grains, fruits, beans and legumes, and instead now eat more fatty foods, and more cholesterol-rich meats. As a result, most people now have far more cholesterol in their bodies than is necessary, and for some people, high levels of cholesterol increase the risk of many diseases.

The solution is not to make our bodies cholesterol-free; the solution is to change one’s diet to reduce the excess added cholesterol.

Cholesterol used to build bile

Structure of cholic acid Bile Liver

from Wikimedia by Mcstrother. CC BY 3.0

Cholesterol used to build hormones

Steroid hormones by Gianpiero Pescarmona

Cholesterol used in all cell membranes

Cholesterol in membrane

Image from sliderbase.com/spitem-808-1.html

 

References

Cholesterol & heart disease – there is a relationship, but it’s not what you think

 

Kidshealth.org – Liver

933a5-humandigestivesystemforkids

 

 

How does bile break up fat?

Think of washing dishes after dinner, without using detergent. Very hard to clean the plates. The fats in your food aren’t water soluble, so they clump together, stick to surfaces, and are hard to remove.

Now add detergent: that’s a two-sided molecule. One side attracts water, while the other side attracts a fat.  Once the water, fat and detergent are all held together, it is easy for fats to dissolve. Dishes can be cleaned.

Same thing for digesting food. Your body can’t digest clumped up fats. Your digestive enzymes only touch the fats on the outside of clumps.  But now that we add bile, it acts like a detergent. Water and fat are held together, so the clumps break up, and the small bits are now easily digested.

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