The liver is one of the most important organs in the human body, providing essential nutrients, metabolizing and detoxifying toxic substances that are accidentally ingested in our daily lives, and keeping our body in a healthy state. At every moment of your work and life, the liver is also working silently and uninterruptedly.
(A) Can the liver be touched?
The liver is the largest substantial organ in the human body, accounting for 2% of body weight in adults, about 1200 grams to 1500 grams, and 5% of body weight in newborns. The adult liver is about 25 cm in length, 15 cm in upper and lower diameter, and 16 cm in front and behind diameter, and it is located in the upper right of the abdominal cavity. The lower part of the liver is adjacent to the stomach, colon and pancreas. The liver is divided into two parts, the left and the right – two lobes, the right lobe being large and thick and the left lobe small and thin. The right half of the liver – the right lobe – is mostly hidden behind the right rib cage, with its upper border between the fifth ribs and its lower border not exceeding the lower edge of the right rib cage. Therefore, the normal liver is not palpable at the lower edge of the right rib in the abdomen (in pediatric patients the liver is palpable below the lower edge of the rib cage). The left lobe of the liver is palpable at what is often referred to as the “fossa of the heart” (under the saber).
(B) The liver – the chemical processing plant of the human body
The liver is composed of hepatocytes, which command 2.5 billion hepatocytes, and every 5,000 hepatocytes form a square – a lobule. Each hepatocyte contains many complex microstructures: such as hepatocyte nucleus, hepatoplasm, mitochondria, endoplasmic reticulum and other components. Each of these microstructures has an extremely important and complex function. The liver is like a huge “chemical processing plant” in the human body. Every day, the liver carries out more than 500 kinds of biochemical reactions, which are closely related to human life activities.
1.The sweet business – sugar metabolism
The main function of sugar is to supply the energy needed for the body’s life activities. According to the Chinese diet, the main component of rice and steamed buns eaten every day is starchy material, i.e. carbohydrates (sugar), which is digested by the gastrointestinal tract and turned into glucose absorbed by the intestine, and enters the liver through the portal vein, where the liver cells synthesize glucose into liver glycogen and store it in the liver through a series of chemical reactions. When glucose in the blood is consumed by life activities, the amount of glucose in the blood decreases, and the liver cells can break down the glucose into glucose to replenish the blood. When glucose is “burned”, it produces carbon dioxide, water, heat and high-energy substances to maintain body temperature and supply energy for human activities. As you can see, the liver plays an important regulatory role when blood glucose levels in the blood change. But too much sugar can also be converted into fat in the liver, so eating too much sugary food, easy to cause obesity.
2, powerful protein synthesis and processing workshop
Daily diet of meat, chicken, fish, eggs or soybeans and other substances rich in protein, protein plays a key role in life. But is the protein in the diet can be directly used by the body? In fact, protein in food is digested by the gastrointestinal tract and broken down into amino acids (raw materials for protein synthesis), which are absorbed through the intestine and enter the liver through the portal vein. The liver is the most important organ for protein synthesis in the human body. In addition to providing the constantly renewed protein needs of the organs and tissues in the body, it is also capable of synthesizing plasma albumin and globulin. Albumin plays an important role in preventing edema and ascites formation. Once the protein synthesis capacity of the liver decreases in patients with liver disease and albumin synthesis is reduced, patients may develop ascites and edema. Globulins are the defenders of the body’s defense system, giving rapid blows to viruses and bacteria that invade the organism. We often talk about various antibodies, which are composed of globulins; therefore, patients with liver disease show a decrease in the body’s resistance – immune function – related to reduced synthesis of globulins when the disease progresses to an advanced stage.
While the proteins are functioning, ammonia is continuously produced, and too much ammonia will have serious toxic effects on the organism. The processing of ammonia also takes place in the liver, which processes it into non-toxic urea, which is excreted from the kidneys via the urine. A normal adult excretes approximately 30 grams of urea in the urine overnight. If liver function fails and the ability to process ammonia is lost, “ammonia toxicity” – hepatic coma – can occur, which can be life-threatening. As you can see, the liver has the role of synthesizing proteins, but also the responsibility of processing its metabolites.
3, the liver’s amazing detoxification function
Surprisingly, fertilizer plant synthetic urea requires high temperature, high pressure (even up to 2 atmospheres) to get the product, and the liver with what magic can get the same product without a sound? This is because the liver can generate a special protein – enzymes, a variety of enzymes in the normal body environment, can be like a catalyst in chemical reactions, can accelerate the speed of various biochemical reactions, including the decomposition, synthesis, oxidation and transformation of sugar, protein, urea, fat, bile acids and cholesterol, etc., to transform one substance into another or into several substances.
Because of this, the liver is also a powerful detoxification organ. In addition to detoxifying some harmful wastes produced during the metabolic process of the human body, it can also convert all or part of the small amount of toxins that may be contaminated in daily food, such as arsenic agents, mercury agents, sulfonamides, antibacterial agents, hemiphiles, and toadstools, into non-toxic substances through oxidation, reduction, hydrolysis and binding, and excrete them out of the body to protect the human body from poisoning. If the liver becomes diseased, its detoxification effect is bound to be weakened. At this time, if drugs are abused indiscriminately, the burden on the liver is bound to increase, and it is easy to cause the progress of the original hepatitis lesion, chronicity, and even aggravation of the disease.
4, the origin of fatty liver – fat metabolism
The fatty substances in the diet are digested by the gastrointestinal tract and the action of bile, and eventually decomposed into fatty acids and glycerol, which are absorbed by the intestine and enter the liver through the portal vein. The liver plays a key role in fat storage and metabolism. Fat in the liver is mainly derived from food and adipose tissue in the periphery of the body. Excessive intake of fat, excessive decomposition of adipose tissue, increased synthesis of triglycerides in the liver, low clearance of fatty acids in the liver, and impaired synthesis of lipoproteins in the liver can all lead to the occurrence of fatty liver.
5.Liver and vitamins
In addition to sugar, protein and fat, which are the basic substances for life activities, human life is also inseparable from the need for vitamins (vitamins). Many kinds of vitamins such as A, B, C, D and K synthesis and storage are closely related to the liver. Abnormalities in vitamin metabolism can occur when the liver is damaged. In the case of hepatitis or other liver diseases, routine use of B vitamins and vitamin C is beneficial for recovery from liver disease.
6. Liver and hormones
Some patients with chronic liver disease will have some embarrassing problems. Male patients will have breast development, loss of libido, impotence and testicular atrophy; female patients are often accompanied by menstrual disorders. Most patients present with redness around the palms of the hands, which are the liver palms often mentioned by doctors, and small spider-like red dots (spider nevi) on the skin of the forehead or neck. These phenomena are all signs of decreased liver function. Because estrogen is broken down and metabolized in the liver, when liver function is damaged for a long time, there will be an imbalance in the ratio of sex hormones, so that the above phenomena occur.
(iii) Killer of invaders – the liver’s defense system
The liver is not only capable of producing but also of defending and killing enemies. The liver’s defense system consists of two main types, humoral immunity and cellular immunity, and different defense systems are used according to the invading enemy, the pathogen. Humoral immunity is mainly a variety of antibodies, which are globulins produced by the liver, and are highly targeted. Once an external enemy invades, the antibodies quickly extinguish it. The cellular immunity of the liver is the presence of special cells in the liver such as macrophages and reticuloendothelial cells, which can engulf, digest and remove harmful substances such as microorganisms and foreign bodies absorbed in the blood and through the intestine. The two together are what we often refer to as the immune function. Thus, it can be seen that the liver is closely related to the immune function of the body. When the liver function is impaired, the patient’s resistance is low and he or she is easily infected with other diseases.
(D) The creator of bile
Many friends with liver disease often ask how jaundice is formed. Jaundice is actually a clinically significant yellowing of the skin, sclera (whites of the eyes) and urine due to the retention and increase of bilirubin in the blood, which is called “jaundice. Bilirubin is one of the components of bile. Bile is synthesized by liver cells, injected into the gallbladder through the small bile duct, concentrated in the gallbladder, and secreted into the duodenum as a digestive fluid, which is indispensable for digestion of fats. In addition to water and bile acids, bile also contains bilirubin. Bilirubin is a dark brown substance produced by the decay of aging red blood cells, and is a harmful substance that the body does not need. It can be said that bile synthesized by the liver has two functions: secretion of digestive juices and excretion of harmful substances.
The formation of jaundice can be simply divided into three causes.
1, excessive sources: due to drug poisoning, malaria and other diseases, a large number of red blood cells destroyed, bilirubin production increased more than the liver’s ability to process secretion, caused by jaundice, called “hemolytic jaundice”.
2, liver function damage: when the liver cells because of inflammation (such as hepatitis) or poisoning so that the function of the liver cells are damaged, the liver cells can not process and secrete bilirubin into the bile ducts, can also lead to increased retention of bilirubin in the blood and cause jaundice, called “hepatocellular jaundice”.
3, obstruction: bile duct channel obstruction (such as cholecystitis, gallstones, bile duct tumors, etc.), bile can not be discharged into the intestine, can also cause jaundice, called “obstructive jaundice”. Under normal circumstances, bilirubin is excreted into the intestine and turns into fecal bile and fecal bile, causing the stool to turn yellow. Therefore, we often see patients with obstructive jaundice who have white clay-colored stools due to the absence of fecal bile and fecal bile in the stool. Due to the lack of bile and pancreatic juice in the intestine, fat cannot be digested, and the stool becomes thin and oily, and a large number of fat globules or fat droplets can be seen under the microscope, which is often called “steatorrhea” by doctors.
(E) The protector of life – liver repair system
In daily life, there are inevitably bumps and bruises, and skin injuries bleed, yet it seems easy to stop the bleeding. This is due to the presence of clotting factors in the blood. Almost all clotting factors are made by the liver. Most of these clotting factors are also proteins. However, it is not the case that more clotting factors are better; a common cerebral thrombosis is the result of too many clotting factors. In order to regulate the hemostatic state of the body, the liver has another function, the anticoagulant system, which plays an important role in regulating the dynamic balance between the two systems of coagulation and anticoagulation in the body. The liver is truly the protector of life.
(vi) The powerful vitality of the liver
The liver has a lot of tasks to perform and many opportunities to suffer blows. However, the liver is not as fragile as people think. A normal liver has a very strong “regenerative power” and “reserve”. As long as a quarter of a normal liver remains, the body can maintain normal functioning. If two-thirds of the liver is cut off due to disease, we can live just as well as long as the remaining liver is normal. Even the remaining one-third of the liver can grow back to 80% of its original size after one year due to the liver’s strong regenerative power.
However, if the liver has become sclerotic due to the destruction of hepatitis and alcohol, the liver loses the ability to regenerate, and even if a small part of the liver is cut off at this time, it may cause insufficient liver function and life-threatening conditions.
(G) Liver and gallbladder – best friend gallbladder
In addition to the location of the gallbladder close to the fossa below the liver, they are also closely related in function. The liver cells produce and secrete bile, which is transported by the bile duct to the gallbladder and finally discharged to the intestine via the common bile duct. The liver produces 800 to 1,000 ml of bile per day, and its main function is to aid in the digestion and absorption of fats in the small intestine. In the event of inflammation or stones in the gallbladder, the liver may also be damaged, affecting the digestive and absorption functions.
As mentioned above, the liver has an extremely complex and delicate structure, and its functions are extremely diverse and important. As you can imagine, the liver is as essential to the human body as an engine is to a car.