What is the liver?
The liver is a reddish-brown organ in the upper right belly, weighing about 1.5 kg.
It’s part of the hepatobiliary system, which also includes the gallbladder and bile ducts. ‘Hepatic’ comes from the Greek word hepar, meaning liver – so when your liver is inflamed, it’s called hepatitis.
Its job is to clean your blood, make proteins, store energy and help digest food.
What is inside the liver?
Inside the liver, there are two key structures that help it do its many jobs:
- Hepatocytes – main liver cells
They clean toxins from your blood, store energy and make bile, clotting factors and other important proteins your body needs. - Bile ducts
These tiny tubes carry bile from the liver to the gallbladder or intestine to help break down fats.
It’s basically a busy little factory with its own delivery system, sending bile to the bowel and proteins and other molecules to the bloodstream.
How is the bile produced?
The bile is a digestive fluid made by the liver main cells – hepatocytes. It is mostly made up of water, cholesterol, bile salts and bilirubin.
The hepatocytes get most of what they need to make bile from the blood and from what they can make themselves.
Water and bilirubin come from the blood, while the liver makes bile salts and most of the cholesterol, though it can also take in some cholesterol from the blood.
The hepatocytes release the bile into tiny channels called bile canaliculi that run between the cells.
These little channels come together to form bigger tubes inside the liver, which eventually connect to the bile duct. The bile duct then carries the bile either to the gallbladder for storage or straight to the intestine to help digest fats.
The liver and the clotting factors
The liver makes most of your body’s clotting factors – the proteins that help your blood stop bleeding.
To make them, the hepatocytes use amino acids from the food you eat, which are carried to it through the bloodstream.
Some clotting factors also need vitamin K, which comes from your diet or your gut bacteria.
Inside the hepatocytes, a few other little ingredients get added to finally produce the different clotting factors. Once they are ready, they get released into the bloodstream. The reason your blood doesn’t clot right away is that these factors leave the liver in an inactive form.
When your tissues or blood vessels get damaged, platelets rush to the site and form a temporary plug. At the same time, the damaged area attracts clotting factors. When these factors come into contact with substances released by the injury, they get activated, helping to form a stable clot -while the rest of your blood keeps flowing normally to other organs.
The liver as energy producer and storage centre
After you eat, the liver takes in extra sugar (glucose) from the bloodstream and turns it into glycogen, a short-term energy reserve. It also converts leftover carbs and proteins into fat, which gets stored for long-term energy.
Most of that fat gets released into your bloodstream and stored in places like your belly, around your organs and under your skin.
The body doesn’t rely on glucose alone. The breakdown of proteins into amino acids is mainly used to build and repair your tissues. But when you need extra energy – like between meals, during long exercise, or when you haven’t eaten -the liver can convert some amino acids into new glucose. At the same time, fats provide long-term energy: when glucose runs low, the body breaks down stored fat to use as fuel for many organs.
So in a way, the liver is both your pantry and your power plant. It stores energy when food is plentiful and produces energy when you need a boost, keeping your blood sugar balanced and your body fueled around the clock.
However, things need to stay in balance – if you regularly overeat, the liver gets flooded with more fuel than it can handle. When that happens, it starts turning a lot of the excess into fat, and some of that fat can build up inside the liver itself, leading to what’s known as fatty liver.
This buildup happens even faster when the diet is high in sugar, fructose-heavy foods – like fruit juice, alcohol and processed foods, because these send a sudden rush of easily absorbed fuel straight to the liver, overwhelming it and making it store more fat.
Recent studies also show that highly processed diets (high in sugar, fat and cholesterol) are quickly absorbed in the small intestine, leaving little for the beneficial bacteria in the large intestine. This causes an imbalance that favours bacteria that trigger inflammation. The result is a ‘leaky gut’ and increased fat production by the liver. Harmful substances from the gut can then reach the liver, adding to inflammation and worsening the liver damage. In short, it’s a mix of diet, gut bacteria imbalance, extra fat production and inflammation that drive the process!
The liver as a blood filter
Blood from the digestive system and spleen flows directly to the liver through the portal vein, carrying nutrients, toxins and other substances absorbed from the food you eat. The liver decides what to keep, what to store and what to remove.
Harmful substances, like drugs, alcohol or metabolic waste, are broken down and neutralised by liver cells, preventing them from circulating throughout the body and causing harm.
The hepatocytes process nutrients, storing or releasing them as needed, and detoxify chemicals. Similar to the spleen, the tiny vessels inside the liver, called sinusoids, are lined with Kupffer cells – a type of immune cell that engulfs bacteria, worn-out blood cells and debris. While the spleen does most of the blood ‘cleanup’, the liver acts as a second filter, catching anything that slips through and recycling important components.
The liver also recycles important components of the blood. It breaks down old red blood cells, salvages iron and converts haemoglobin into bilirubin, which is eventually excreted in bile.
By filtering out toxins and recycling valuable materials, the liver keeps your blood not only clean, but also rich in nutrients your body can use, acting as both a detox centre and a recycling hub.
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