What are dimensions of the small intestine? What are reasons to explain why the small intestine Where does the process of digestion begin? Are nutrients absorbed from the large intestine? How do nutrients, absorbed by the small intestine, travel to the individual cells of the human body? Is the pH of the small intestine lower or higher than that of the stomach?
Why is the pH of the Why is the stomach such a muscular organ? How is the stomach lining adapted to its function? Hepatocytes also initiate the formation and secretion of bile. Hepatocytes are organized into plates separated by vascular channels sinusoids for blood vessels. The hepatocyte plates are one cell thick in mammals. Hepatocytes are unique in that they are one of the few types of cell in the human body that are capable of regeneration. Hepatocytes are derived from hepatoblasts, the precursor stem cell of the liver that divides to produce new hepatocytes.
In the hepatic portal system, the liver receives a dual blood supply from the hepatic portal vein and the hepatic arteries. In the hepatic portal system, the liver receives a dual blood supply from the hepatic portal vein and hepatic arteries. The hepatic arteries supply arterial blood to the liver and account for the remainder of its blood flow. Blood flows through the liver tissue and empties into the central vein of each lobule. The central veins coalesce into hepatic veins that collect the blood leaving the liver and bring it to the heart.
Hepatic veins : An image of a liver with the hepatic veins labeled. They are located in the inferior vena cava. A portal system is a venous structure that enables blood from one set of capillary beds to drain into another set of capillary beds, without first returning this blood to the heart.
The majority of capillaries in the body drain directly into the heart, so portal systems are unusual. The hepatic portal system connects the capillaries of the gastrointestinal tract with the capillaries in the liver. Nutrient-rich blood leaves the gastrointestinal tract and is first brought to the liver for processing before being sent to the heart. Here, carbohydrates and amino acids can be stored or used to make new proteins and carbohydrates.
The liver also removes vitamins and cofactors from the blood for storage, as well as filters any toxins that may have been absorbed along with the food. When any of these stored substances are needed, the liver releases them back into circulation through the hepatic veins. Hepatic portal circulation : A diagram that shows the hepatic portal vein and its territory.
The human liver is thought to be responsible for up to separate functions, usually in combination with other systems and organs. The various functions of the liver are carried out by the liver cells or hepatocytes. Currently, there is no artificial organ or device capable of emulating all the functions of the liver. The liver : The liver, or hepar, is a vital organ present in vertebrates and some other animals.
It has a wide range of functions including detoxification, protein synthesis, and the production of the biochemicals necessary for digestion. The liver is the mainstay of protein metabolism— it synthesizes as well as degrades. It performs several roles in carbohydrate and lipid metabolism. The bulk of the lipoproteins are synthesized in the liver. Liver tissue of an alcoholic : A healthy liver can break down alcohol. However, the overstressed liver of an alcoholic may become clogged with fats that adversely affect liver function.
In the first- trimester fetus, the liver is the main site of red blood cell production. By the 32nd week of gestation, the bone marrow has almost completely taken over that task. The liver also produces the insulin -like growth factor 1 IGF-1 , a polypeptide protein hormone that plays an important role in childhood growth and continues to have anabolic effects in adults. The liver is responsible for immunological effects, acting as a sieve for the antigens that are carried to it via the portal system.
The liver synthesizes angiotensinogen, a hormone that is responsible for raising blood pressure when the angiotensinogen is activated by renin, an enzyme that is released when the kidney senses low blood pressure. The liver breaks down or modifies toxic substances, such as alcohol and most medicinal products, in a process called drug metabolism.
This sometimes results in toxication, when the metabolite is more toxic than its precursor. Preferably, the toxins are conjugated to avail excretion in bile or urine. The liver breaks down insulin and other hormones. Bile is a fluid produced by the liver that aids the process of digestion and the absorption of lipids in the small intestine.
Bile : Micrograph of bile yellow material in a liver biopsy. The duct from the liver hepatic duct and the duct from the gallbladder cystic duct meet to form the common bile duct. The common bile duct carries bile to the duodenum. The first part of the small intestine. When bile leaves the liver, it flows through the bile ducts into the duodenum. Here, bile starts mixing with food to help digest fat. An organ that filters blood. It also helps keep your body healthy and free of infection, as part of the immune system.
Hepatic portal vein. A blood vessel that carries blood containing nutrients and oxygen from the digestive tract and spleen into the liver. Inferior vena cava. A large vein that carries blood from the liver, intestines, legs, and kidneys to the heart. Hepatic artery. A blood vessel that carries blood with a fresh supply of oxygen into the liver from the heart.
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