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Cholangiocytes
Cholangiocytes are the epithelial cells of the bile duct. They are cuboidal epithelium in the small interlobular bile ducts, but become columnar and HCO3:-secreting in larger bile ducts approaching the porta hepatis and the extrahepatic ducts. They contribute to hepatocyte survival by transporting bile acids. Function In the healthy liver, cholangiocytes contribute to bile secretion via release of bicarbonate and water. Several hormones and locally acting mediators are known to contribute to cholangiocyte fluid/electrolyte secretion. These include secretin, acetylcholine, ATP, and bombesin. Cholangiocytes act through bile-acid independent bile flow, which is driven by the active transport of electrolytes. In contrast, hepatocytes secrete bile through bile-acid dependent bile flow, which is coupled to canalicular secretion of bile acids via ATP-driven transporters. This results in passive transcellular and paracellular secretion of fluid and electrolytes through an osmotic effect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secretin
Secretin is a hormone that regulates water homeostasis throughout the body and influences the environment of the duodenum by regulating secretions in the stomach, pancreas, and liver. It is a peptide hormone produced in the S cells of the duodenum, which are located in the intestinal glands. In humans, the secretin peptide is encoded by the SCT gene. Secretin helps regulate the pH of the duodenum by (1) inhibiting the secretion of gastric acid from the parietal cells of the stomach and (2) stimulating the production of bicarbonate from the ductal cells of the pancreas. It also stimulates the secretion of bicarbonate and water by cholangiocytes in the bile duct, protecting it from bile acids by controlling the pH and promoting the flow in the duct. Meanwhile, in concert with secretin's actions, the other main hormone simultaneously issued by the duodenum, cholecystokinin (CCK), is stimulating the gallbladder to contract, delivering its stored bile. Prosecretin is a precursor to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biliary Atresia
Biliary atresia, also known as extrahepatic ductopenia and progressive obliterative cholangiopathy, is a childhood disease of the liver in which one or more bile ducts are abnormally narrow, blocked, or absent. It can be congenital or acquired. It has an incidence of one in 10,000–15,000 live births in the United States, and a prevalence of one in 16,700 in the British Isles. Biliary atresia is most common in East Asia, with a frequency of one in 5,000. The cause of biliary atresia in Egyptian infants has been proven to be as a result of aflatoxin induced cholangiopathy acquired prenatally in infants who have glutathione S transferase M1 deficiency. The biliary atresia phenotype caused by congenital aflatoxicosis in GST M1 deficient neonates is named Kotb disease. Syndromic biliary atresia (e.g. Biliary Atresia Splenic Malformation (BASM)) has been associated with certain genes (e.g. Polycystic Kidney Disease 1 Like 1 - PKD1L1), and some infants with isolated biliary atresia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Sclerosing Cholangitis
Primary sclerosing cholangitis (PSC) is a long-term progressive disease of the liver and gallbladder characterized by inflammation and scarring of the bile ducts, which normally allow bile to drain from the gallbladder. Affected individuals may have no symptoms or may experience signs and symptoms of liver disease, such as yellow discoloration of the skin and eyes, itching, and abdominal pain. The bile duct scarring that occurs in PSC narrows the ducts of the biliary tree and impedes the flow of bile to the intestines. Eventually, it can lead to cirrhosis of the liver and liver failure. PSC increases the risk of various cancers, including liver cancer, gallbladder carcinoma, colorectal cancer, and cholangiocarcinoma. The underlying cause of PSC is unknown. Genetic susceptibility, immune system dysfunction, and abnormal composition of the gut flora may play a role. This is further suggested by the observation that around 75% of individuals with PSC also have inflammatory bowe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylcholine
Acetylcholine (ACh) is an organic chemical that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Parts in the body that use or are affected by acetylcholine are referred to as cholinergic. Substances that increase or decrease the overall activity of the cholinergic system are called cholinergics and anticholinergics, respectively. Acetylcholine is the neurotransmitter used at the neuromuscular junction—in other words, it is the chemical that motor neurons of the nervous system release in order to activate muscles. This property means that drugs that affect cholinergic systems can have very dangerous effects ranging from paralysis to convulsions. Acetylcholine is also a neurotransmitter in the autonomic nervous system, both as an internal transmitter for the sympathetic nervous system and as the final product released by the parasymp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelial Cells
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithelia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver Transplantation
Liver transplantation or hepatic transplantation is the replacement of a diseased liver with the healthy liver from another person (allograft). Liver transplantation is a treatment option for end-stage liver disease and acute liver failure, although availability of donor organs is a major limitation. The most common technique is orthotopic transplantation, in which the native liver is removed and replaced by the donor organ in the same anatomic position as the original liver. The surgical procedure is complex, requiring careful harvest of the donor organ and meticulous implantation into the recipient. Liver transplantation is highly regulated, and only performed at designated transplant medical centers by highly trained transplant physicians and supporting medical team. The duration of the surgery ranges from 4 to 18 hours depending on outcome. Favorable outcomes require careful screening for eligible recipient, as well as a well-calibrated live or cadaveric donor match. Medi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cystic Fibrosis
Cystic fibrosis (CF) is a rare genetic disorder that affects mostly the lungs, but also the pancreas, liver, kidneys, and intestine. Long-term issues include difficulty breathing and coughing up mucus as a result of frequent lung infections. Other signs and symptoms may include sinus infections, poor growth, fatty stool, clubbing of the fingers and toes, and infertility in most males. Different people may have different degrees of symptoms. Cystic fibrosis is inherited in an autosomal recessive manner. It is caused by the presence of mutations in both copies of the gene for the cystic fibrosis transmembrane conductance regulator (CFTR) protein. Those with a single working copy are carriers and otherwise mostly healthy. CFTR is involved in the production of sweat, digestive fluids, and mucus. When the CFTR is not functional, secretions which are usually thin instead become thick. The condition is diagnosed by a sweat test and genetic testing. Screening of infants at bi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alagille's Syndrome
Alagille syndrome is a genetic disorder that affects primarily the liver and the heart. Problems associated with the disorder generally become evident in infancy or early childhood. The disorder is inherited in an autosomal dominant pattern, and the estimated prevalence of Alagille syndrome is 1 in every 30,000 to 1 in every 40,000 live births. It is named after the French pediatrician Daniel Alagille, who first described the condition in 1969. Signs and symptoms The severity of the disorder can vary within the same family, with symptoms ranging from so mild as to go unnoticed, to severe heart and/or liver disease that requires transplantation. It is uncommon, but Alagille syndrome can be a life-threatening disease with a mortality rate of 10%. The majority of deaths from ALGS are typically due to heart complications or chronic liver failure. Liver Signs and symptoms arising from liver damage in Alagille syndrome may include a yellowish tinge in the skin and the whites of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Primary Biliary Cirrhosis
Primary biliary cholangitis (PBC), previously known as primary biliary cirrhosis, is an autoimmune disease of the liver. It results from a slow, progressive destruction of the small bile ducts of the liver, causing bile and other toxins to build up in the liver, a condition called cholestasis. Further slow damage to the liver tissue can lead to scarring, fibrosis, and eventually cirrhosis. Common symptoms are tiredness, itching, and in more advanced cases, jaundice. In early cases, the only changes may be those seen in blood tests. PBC is a relatively rare disease, affecting up to one in 3,000–4,000 people. It is much more common in women, with a sex ratio of at least 9:1 female to male. The condition has been recognised since at least 1851, and was named "primary biliary cirrhosis" in 1949. Because cirrhosis is a feature only of advanced disease, a change of its name to "primary biliary cholangitis" was proposed by patient advocacy groups in 2014. Signs and symptoms Pe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatocytes
A hepatocyte is a cell of the main parenchymal tissue of the liver. Hepatocytes make up 80% of the liver's mass. These cells are involved in: * Protein synthesis * Protein storage * Transformation of carbohydrates * Synthesis of cholesterol, bile salts and phospholipids * Detoxification, modification, and excretion of exogenous and endogenous substances * Initiation of formation and secretion of bile Structure The typical hepatocyte is cubical with sides of 20-30 μm, (in comparison, a human hair has a diameter of 17 to 180 μm).The diameter of human hair ranges from 17 to 181 μm. The typical volume of a hepatocyte is 3.4 x 10−9 cm3. Smooth endoplasmic reticulum is abundant in hepatocytes, in contrast to most other cell types. Microanatomy Hepatocytes display an eosinophilic cytoplasm, reflecting numerous mitochondria, and basophilic stippling due to large amounts of smooth endoplasmic reticulum and free ribosomes. Brown lipofuscin granules are also observed ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bombesin
Bombesin is a 14-amino acid peptide originally isolated from the skin of the European fire-bellied toad (''Bombina bombina'') by Vittorio Erspamer ''et al.'' and named after its source. NIHMSID 45053. It has two known homologs in mammals called neuromedin B and gastrin-releasing peptide. It stimulates gastrin release from G cells. It activates three different G-protein-coupled receptors known as BBR1, -2, and -3. It also activates these receptors in the brain. Together with cholecystokinin, it is the second major source of negative feedback signals that stop eating behaviour. Bombesin is also a tumor marker for small cell carcinoma of lung, gastric cancer, pancreatic cancer, and neuroblastoma. Receptors The anuran receptor homologue is termed (). Iwabuchi ''et al.'' 2003 discovered a chicken (''Gallus domesticus'') receptor which is homologous to both the and fBB4 and so they named it . Effects Erspamer 1988 finds bombesin has a similar effect on the chicken to ranatensin, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adenosine Triphosphate
Adenosine triphosphate (ATP) is an organic compound that provides energy to drive many processes in living cells, such as muscle contraction, nerve impulse propagation, condensate dissolution, and chemical synthesis. Found in all known forms of life, ATP is often referred to as the "molecular unit of currency" of intracellular energy transfer. When consumed in metabolic processes, it converts either to adenosine diphosphate (ADP) or to adenosine monophosphate (AMP). Other processes regenerate ATP. The human body recycles its own body weight equivalent in ATP each day. It is also a precursor to DNA and RNA, and is used as a coenzyme. From the perspective of biochemistry, ATP is classified as a nucleoside triphosphate, which indicates that it consists of three components: a nitrogenous base (adenine), the sugar ribose, and the Polyphosphate, triphosphate. Structure ATP consists of an adenine attached by the 9-nitrogen atom to the 1′ carbon atom of a sugar (ribose), which i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
