Liver facts for kids
Quick facts for kids Liver |
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| The human liver is located in the upper right abdomen | |
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| Location of human liver (in red) shown on a male body | |
| Latin | jecur, iecur |
| System | Digestive system |
| Artery | Hepatic artery |
| Vein | Hepatic vein and hepatic portal vein |
| Nerve | Celiac ganglia and vagus nerve |
| Precursor | Foregut |
The liver is a super important organ found in all animals with a backbone. It does many essential jobs to keep your body healthy. Think of it as your body's own amazing chemical factory! It helps clean out harmful stuff, makes important proteins, and creates chemicals needed for digestion and growth.
In humans, your liver sits in the upper right part of your abdomen, just under your diaphragm. It's mostly protected by your lower right rib cage. The liver also helps manage your body's energy by storing and converting nutrients like glucose (sugar) and glycogen. It even helps break down old red blood cells. When you hear words like "hepatology" (the study of the liver) or "hepatitis" (liver inflammation), the "hepat-" part comes from the Greek word for liver.
Your liver also makes a special fluid called bile. Bile is like a natural soap that helps break down the fats in the food you eat. A small pouch called the gallbladder stores this bile until it's needed for digestion in your duodenum (the first part of your small intestine). The liver's special cells, called hepatocytes, handle hundreds of important chemical reactions every day. Because it does so many vital tasks, your body cannot live without a working liver. Scientists are still working on ways to fully replace liver function if it fails, but for now, a liver transplantation is often the only long-term solution for complete liver failure.
What is the Liver?
The liver is a large, reddish-brown organ shaped like a wedge. It's the heaviest internal organ and the largest gland in your body. An adult human liver usually weighs about 1.5 kilograms (3.3 pounds) and is about 15 centimeters (6 inches) wide. Its size can vary quite a bit from person to person.
How Your Liver is Built
Your liver has a complex structure that allows it to perform all its many jobs. It's divided into different sections and contains tiny working units.
Main Parts of the Liver
When you look at the liver from above, it seems to have two main parts: a right lobe and a left lobe. From below, it looks like it has four parts. A special band of tissue called the falciform ligament helps divide the liver into these left and right sections.
The liver's surface that faces your diaphragm is smooth and curved. Most of it is covered by a thin, double-layered membrane called the peritoneum. This membrane helps reduce friction when your organs move. The surface facing your other organs is uneven and has special indentations. These "impressions" are like little hollows where other organs, such as your gallbladder, stomach, kidney, and duodenum, press against the liver.
Tiny Liver Units
Under a microscope, you can see that the liver is made up of millions of tiny working units called hepatic lobules. Each lobule is shaped roughly like a hexagon. These lobules contain millions of hepatocytes, which are the main cells that do all the liver's work.
The lobules are held together by a strong, fibrous layer called Glisson's capsule. This capsule covers the entire liver. Inside each lobule, you'll find a "portal triad" at each corner. This triad is a group of three important tubes: a branch of the hepatic artery, a branch of the portal vein, and a small bile duct.
Blood Flow to Your Liver
Your liver gets blood from two major blood vessels. The hepatic artery brings fresh, oxygen-rich blood from your aorta. The hepatic portal vein carries blood full of digested nutrients from your entire gastrointestinal tract, as well as from your spleen and pancreas.
These blood vessels branch out into tiny capillaries called liver sinusoids within the liver lobules. After flowing through these sinusoids, the blood collects in central veins, which then join to form the hepatic veins. These hepatic veins carry blood away from the liver and into your inferior vena cava, which takes it back to your heart.
How Your Liver Grows
The liver starts to form very early, between the third and eighth week of embryonic development (when a baby is growing inside its mother). It develops from parts of the early digestive tube and surrounding tissues.
Liver Development Before Birth
Before a baby is born, the liver plays a special role in making blood cells. It's also a major pathway for nutrients coming from the mother through the umbilical vein. This vein carries nutrient-rich blood directly to the growing baby. A special bypass, called the ductus venosus, allows some of this blood to go straight to the heart, avoiding the liver's filtering system because the mother's body is doing the filtering.
After birth, the umbilical vein and ductus venosus close up. The liver then takes on its full role in digestion and filtering. At birth, a baby's liver makes up about 4% of its body weight. As the child grows, the liver gets much bigger, eventually weighing about 1.4 to 1.6 kilograms (3 to 3.5 pounds) in an adult, but it will make up a smaller percentage of the total body weight.
Amazing Jobs Your Liver Does
Your liver is incredibly busy, performing around 500 different tasks! No artificial organ can do everything your liver does. Here are some of its most important functions:
Managing Your Energy (Carbohydrates)
The liver is key to how your body uses energy from carbohydrates:
- It stores extra sugar (glucose) as glycogen, like a fuel tank, through a process called glycogenesis.
- When your body needs energy, the liver breaks down this stored glycogen back into glucose, releasing it into your blood. This is called glycogenolysis.
- It can even make new glucose from other sources, like certain amino acids or fats, a process known as gluconeogenesis.
Building Blocks (Proteins)
Your liver is a protein powerhouse:
- It makes almost all the plasma proteins found in your blood, which are vital for many body functions.
- It creates important coagulation factors that help your blood clot when you get a cut, preventing too much bleeding.
- The liver also produces thrombopoietin, a hormone that tells your bone marrow to make platelets, which are tiny cells important for clotting.
Handling Fats
The liver is crucial for processing fats:
- It makes cholesterol and other fats called triglycerides.
- It produces bile, that yellowish fluid stored in the gallbladder, which helps break down dietary fats so your body can absorb them and important vitamins like vitamin K.
Cleaning Up Your Body
Your liver is your body's main detoxifier:
- It breaks down and removes harmful substances, including many medicines, waste products, and toxins.
- It converts ammonia, a toxic waste product, into urea, which your kidneys can then remove from your body through urine.
- It also breaks down bilirubin, a yellow pigment from old red blood cells, so it can be removed from your body.
Storing Important Stuff
The liver acts like a storage locker for essential nutrients:
- It stores large amounts of vitamin A, vitamin D, vitamin B12, vitamin K, and vitamin E.
- It also keeps reserves of important minerals like iron and copper.
Blood and Immune Support
- Your liver can hold a lot of blood, acting as a blood reservoir. It can store up to 1 liter of extra blood if needed.
- It produces about half of all the lymph fluid in your body, which is part of your immune system.
- Special cells in the liver, called Kupffer cells, act like tiny cleaners. They gobble up dead blood cells and bacteria from your blood.
- The liver makes albumin, the most common protein in your blood. Albumin helps keep fluids balanced and carries fats and hormones around your body.
- It also produces angiotensinogen, a hormone that helps control your blood pressure.
When the Liver Needs Help
Because the liver does so many vital jobs, problems with it can affect your whole body.
Common Liver Problems
- Fatty Liver Disease: This is a common condition where too much fat builds up in the liver.
- Hepatitis: This means inflammation of the liver. It's often caused by viruses, like hepatitis A, B, or C. Some types of hepatitis can spread through close contact or shared needles. Long-term infections with hepatitis B or C can sometimes lead to liver cancer.
- Cirrhosis: This is when the liver becomes scarred from long-term damage. It can make it harder for blood to flow through the liver.
- Liver Problems from Alcohol: Drinking too much alcohol can damage the liver, leading to conditions like fatty liver, alcoholic hepatitis, and cirrhosis.
- Drug-Induced Liver Damage: Some medicines, especially if taken incorrectly or in large amounts, can harm the liver.
Signs of Liver Trouble
If your liver isn't working well, you might notice these signs:
- Yellow Skin or Eyes (Jaundice): This happens when a yellow substance called bilirubin builds up in your body.
- Itching: Intense itching is a common complaint for people with liver problems.
- Dark Urine and Pale Stools: Bilirubin can make your urine dark, and if it's not reaching your intestines, your stools might become pale.
- Swelling: Fluid can build up in your abdomen, ankles, and feet because the liver isn't making enough albumin.
- Tiredness: You might feel very tired due to a lack of nutrients.
- Easy Bruising or Bleeding: The liver makes clotting factors, so if it's damaged, you might bruise or bleed more easily.
- Pain: Pain in the upper right part of your abdomen can happen if the liver swells.
Checking Your Liver's Health
Doctors can check your liver's health with liver function tests, which are blood tests. If they suspect an infection, they might do other tests. They can also feel your liver during an exam to check its size. Sometimes, they use medical imaging like an ultrasound or CT scan to get a better look.
In some cases, a liver biopsy is needed. This is when a tiny sample of liver tissue is taken with a needle for closer examination.
The Liver's Superpower: Regeneration
Your liver is the only internal human organ that can naturally regrow lost tissue! Even if a large part of it is removed, the remaining part can grow back to restore its function. This amazing ability is why the ancient Greeks might have known about it, as seen in the myth of Prometheus, whose liver grew back every night after being eaten by an eagle.
Liver Transplants: A New Beginning
For people with severe, irreversible liver failure, a liver transplantation is often the only hope. This is when a diseased liver is replaced with a healthy one from a donor. Most transplants use livers from donors who have passed away.
However, Living donor liver transplantation is also possible. In this procedure, a healthy person donates a part of their liver to someone who needs it. Because the liver can regenerate, both the donor and the recipient can end up with healthy, functioning livers. This is a complex surgery, but it offers a chance at a new life for many.
The Liver in Culture and Food
The liver has been important to humans in many ways throughout history, from ancient beliefs to modern meals.
Liver in Stories and Sayings
In some cultures, the liver was believed to be the home of the soul or strong emotions like courage and anger. For example, in Greek mythology, Prometheus's liver regrew daily. In English, if someone is called 'lily-livered,' it means they are a coward, linking the liver to bravery.
Liver as Food
People around the world commonly eat the livers of animals like pigs, cows, chickens, and fish. Liver is very nutritious, packed with iron, vitamin A, and vitamin B12. Cod liver oil, for example, is a popular dietary supplement.
Liver can be cooked in many ways: baked, boiled, fried, or even made into liver pâté or sausages like liverwurst. It's a versatile food enjoyed in many different cuisines.
The Liver in Other Animals
The liver is found in all vertebrates (animals with backbones) and is usually their largest internal organ. While its exact shape can differ depending on the animal, its basic internal structure and functions are quite similar across species. For example, in snakes, the liver is long and thin to fit their body shape.
Even some very simple chordates, like the amphioxus, have an organ that acts like a liver, performing many of the same jobs, even though it's not considered a "true" liver.
See Also
In Spanish: Hígado para niños
