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Hepatic Plexus
The hepatic plexus is a sympathetic and parasympathetic nerve plexus that provides innervation to the parenchyma of the liver as well as contributing innervation to some other abdominal structures. Its sympathetic component is derived from the coeliac and superior mesenteric plexuses; its parasympathetic component is derived from the anterior and posterior vagal trunks. Anatomy Afferents Sympathetic The plexus receives post-ganglionic sympathetic afferents from the celiac plexus, and the superior mesenteric plexus. The hepatic plexus is the largest derivative of the celiac plexus. Parasympathetic The plexus receives pre-ganglionic parasymathetic afferents primarily from the anterior vagal trunk, with a lesser contribution from the posterior vagal trunk. The anterior vagal trunk issues one or more hepatic branches of anterior vagal trunk that pass in the superior portion of the lesser omentum to reach the hepatic plexus. Efferents and distribution The plexus is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Celiac Ganglia
The celiac ganglia or coeliac ganglia are two large irregularly shaped masses of nerve tissue in the upper abdomen. Part of the sympathetic subdivision of the autonomic nervous system (ANS), the two celiac ganglia are the largest ganglia in the ANS, and they innervate most of the digestive tract. They have the appearance of lymph glands and are placed on either side of the midline in front of the crura of the diaphragm, close to the suprarenal glands (also called adrenal glands). The ganglion on the right side is placed behind the inferior vena cava. They are sometimes referred to as the semilunar ganglia or the solar ganglia. Neurotransmission The celiac ganglion is part of the sympathetic prevertebral chain possessing a great variety of specific receptors and neurotransmitters such as catecholamines, neuropeptides, and nitric oxide and constitutes a modulation center in the pathway of the afferent and efferent fibers between the central nervous system and the ovary. Th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hepatocyte
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 rough endoplasmic reticulum and free ribosomes. Brown lipofuscin granules are also observed (wit ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nerve Plexus
A nerve plexus is a plexus (branching network) of intersecting nerves. A nerve plexus is composed of afferent and efferent fibers that arise from the merging of the anterior rami of spinal nerves and blood vessels. There are five spinal nerve plexuses, except in the thoracic region, as well as other forms of autonomic nervous system, autonomic plexuses, many of which are a part of the enteric nervous system. The nerves that arise from the plexuses have both sensory and motor functions. These functions include muscle contraction, the maintenance of body coordination and control, and the reaction to sensations such as heat, cold, pain, and pressure. There are several plexuses in the body, including: *Spinal plexuses **Cervical plexusserves the head, neck and shoulders **Brachial plexusserves the chest, shoulders, arms and hands **Lumbosacral plexus ***Lumbar plexusserves the back, abdomen, groin, thighs, knees, and calves ****Subsartorial plexusbelow the sartorius muscle of thigh *** ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotransmission
Neurotransmission (Latin: ''transmissio'' "passage, crossing" from ''transmittere'' "send, let through") is the process by which signaling molecules called neurotransmitters are released by the axon terminal of a neuron (the presynaptic neuron), and bind to and react with the receptors on the dendrites of another neuron (the postsynaptic neuron) a short distance away. Changes in the concentration of ions, such as Ca2+, Na+, K+, underlie both chemical and electrical activity in the process. The increase in calcium levels is essential and can be promoted by protons. A similar process occurs in retrograde neurotransmission, where the dendrites of the postsynaptic neuron release retrograde neurotransmitters (e.g., endocannabinoids; synthesized in response to a rise in intracellular calcium levels) that signal through receptors that are located on the axon terminal of the presynaptic neuron, mainly at GABAergic and glutamatergic synapses. Neurotransmission is regulated by severa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Biological Functions Of Nitric Oxide
Biological functions of nitric oxide are roles that nitric oxide plays within biology. Nitric oxide (nitrogen monoxide) is a molecule and chemical compound with chemical formula of N O. In mammals including humans, nitric oxide is a signaling molecule involved in several physiological and pathological processes. It is a powerful vasodilator with a half-life of a few seconds in the blood. Standard pharmaceuticals such as nitroglycerine and amyl nitrite are precursors to nitric oxide. Low levels of nitric oxide production are typically due to ischemic damage in the liver. As a consequence of its importance in neuroscience, physiology, and immunology, nitric oxide was proclaimed " Molecule of the Year" in 1992. Research into its function led to the 1998 Nobel Prize for elucidating the role of nitric oxide as a cardiovascular signalling molecule. Sources of nitric oxide Nitric oxide biosynthesis Platelet-derived factors, shear stress, acetylcholine, and cytokines stimulate the pr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Peptide
Peptides are short chains of amino acids linked by peptide bonds. A polypeptide is a longer, continuous, unbranched peptide chain. Polypeptides that have a molecular mass of 10,000 Da or more are called proteins. Chains of fewer than twenty amino acids are called oligopeptides, and include dipeptides, tripeptides, and tetrapeptides. Peptides fall under the broad chemical classes of biological polymers and oligomers, alongside nucleic acids, oligosaccharides, polysaccharides, and others. Proteins consist of one or more polypeptides arranged in a biologically functional way, often bound to ligands such as coenzymes and cofactors, to another protein or other macromolecule such as DNA or RNA, or to complex macromolecular assemblies. Amino acids that have been incorporated into peptides are termed residues. A water molecule is released during formation of each amide bond.. All peptides except cyclic peptides have an N-terminal (amine group) and C-terminal (carboxyl g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amine
In chemistry, amines (, ) are organic compounds that contain carbon-nitrogen bonds. Amines are formed when one or more hydrogen atoms in ammonia are replaced by alkyl or aryl groups. The nitrogen atom in an amine possesses a lone pair of electrons. Amines can also exist as hetero cyclic compounds. Aniline is the simplest aromatic amine, consisting of a benzene ring bonded to an amino group. Amines are classified into three types: primary (1°), secondary (2°), and tertiary (3°) amines. Primary amines (1°) contain one alkyl or aryl substituent and have the general formula RNH2. Secondary amines (2°) have two alkyl or aryl groups attached to the nitrogen atom, with the general formula R2NH. Tertiary amines (3°) contain three substituent groups bonded to the nitrogen atom, and are represented by the formula R3N. The functional group present in primary amines is called the amino group. Classification of amines Amines can be classified according to the nature and number o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Choline
Choline is a cation with the chemical formula . Choline forms various Salt (chemistry), salts, such as choline chloride and choline bitartrate. An essential nutrient for animals, it is a structural component of phospholipids and cell membranes. Choline is used to synthesize acetylcholine, a neurotransmitter involved in muscle control and numerous functions of the nervous system. Choline is involved in early development of the brain, gene expression, cell membrane Signaling peptide receptor, signaling, and brain metabolism. Although humans synthesize choline in the liver, the amount produced naturally is insufficient to meet cellular functions, requiring that some choline be obtained from foods or dietary supplements. Foods rich in choline include meats, poultry, eggs, and other animal-based products, cruciferous vegetables, beans, nuts, and whole grains. Choline is present in breast milk and is commonly added as an food additive, ingredient to baby foods. Chemistry Choline i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, in particular the large arteries and small arterioles. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in controlling hemorrhage and reducing acute blood loss. When blood vessels constrict, the flow of blood is restricted or decreased, thus retaining body heat or increasing vascular resistance. This makes the skin turn paler because less blood reaches the surface, reducing the radiation of heat. On a larger level, vasoconstriction is one mechanism by which the body regulates and maintains mean arterial pressure. Medications causing vasoconstriction, also known as vasoconstrictors, are one type of medicine used to raise blood pressure. Generalized vasoconstriction usually results in an increase in systemic blood pressure, but it may also occur in specific tissues, causing a localized reduction in b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gastroduodenal Artery
In anatomy, the gastroduodenal artery is a small blood vessel in the abdomen. It supplies blood directly to the pylorus (distal part of the stomach) and proximal part of the duodenum. It also indirectly supplies the pancreatic head (via the anterior and posterior superior pancreaticoduodenal arteries). Structure The gastroduodenal artery most commonly originates from the common hepatic artery, which is a branch of the celiac trunk. Occasionally, it may arise from the proper hepatic artery or from the right or left hepatic arteries, but these are less common anatomical variations. It first gives rise to the supraduodenal artery, followed by the posterior superior pancreaticoduodenal artery. It terminates in a bifurcation when it splits into the right gastroepiploic artery and the anterior superior pancreaticoduodenal artery ( superior pancreaticoduodenal artery). These branches form functional anastomoses with the anterior and posterior inferior pancreaticoduodenal arteries ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pylorus
The pylorus ( or ) connects the stomach to the duodenum. The pylorus is considered as having two parts, the ''pyloric antrum'' (opening to the body of the stomach) and the ''pyloric canal'' (opening to the duodenum). The ''pyloric canal'' ends as the ''pyloric orifice'', which marks the junction between the stomach and the duodenum. The orifice is surrounded by a sphincter, a band of muscle, called the ''pyloric sphincter''. The word ''pylorus'' comes from Greek πυλωρός, via Latin. The word ''pylorus'' in Greek means "gatekeeper", related to "gate" () and is thus linguistically related to the word " pylon". Structure The pylorus is the furthest part of the stomach that connects to the duodenum. It is divided into two parts, the ''antrum'', which connects to the body of the stomach, and the ''pyloric canal'', which connects to the duodenum. Antrum The antrum also called the ''gastric antrum'' or the ''pyloric antrum'' is the initial portion of the pyloric region. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Right Gastric Artery
The right gastric artery usually arises from the proper hepatic artery. It descends to the pyloric end of the stomach The stomach is a muscular, hollow organ in the upper gastrointestinal tract of Human, humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical t ... before passing from right to left along its lesser curvature, supplying it with branches, and finally anastomosing with the left gastric artery. Anatomy Variation Origin In most (53%) individuals, the RGA arises from the proper hepatic artery. It can also arise from the region of division of the common hepatic artery (20%), the left branch of the hepatic artery (15%), the gastroduodenal artery (8%), and - most rarely - the common hepatic artery itself (4%). Additional images File:Gray532.png, The celiac artery and its branches; the liver has been raised, and the lesser omentum and anterior layer of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
