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Sphincter Muscle
A sphincter is a circular muscle that normally maintains constriction of a natural body passage or orifice and relaxes as required by normal physiological functioning. Sphincters are found in many animals. There are over 60 types in the human body, some microscopically small, in particular the millions of precapillary sphincters. Sphincters relax at death, often releasing fluids and faeces. Functioning Each sphincter is associated with the lumen (opening) it surrounds. As long as the sphincter muscle is contracted, its length is shortened and the lumen is constricted (closed). Relaxation of the muscle causes it to lengthen, opening the lumen and allowing the passage of liquids, solids, or gases. This is evident, for example, in the blowholes of numerous marine mammals. Many sphincters are used every day in the normal course of digestion. For example, the lower oesophageal sphincter (or cardiac sphincter), which resides at the top of the stomach, is closed most of the time, k ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle
Muscle is a soft tissue, one of the four basic types of animal tissue. There are three types of muscle tissue in vertebrates: skeletal muscle, cardiac muscle, and smooth muscle. Muscle tissue gives skeletal muscles the ability to muscle contraction, contract. Muscle tissue contains special Muscle contraction, contractile proteins called actin and myosin which interact to cause movement. Among many other muscle proteins, present are two regulatory proteins, troponin and tropomyosin. Muscle is formed during embryonic development, in a process known as myogenesis. Skeletal muscle tissue is striated consisting of elongated, multinucleate muscle cells called muscle fibers, and is responsible for movements of the body. Other tissues in skeletal muscle include tendons and perimysium. Smooth and cardiac muscle contract involuntarily, without conscious intervention. These muscle types may be activated both through the interaction of the central nervous system as well as by innervation ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iris (anatomy)
The iris (: irides or irises) is a thin, annular structure in the eye in most mammals and birds that is responsible for controlling the diameter and size of the pupil, and thus the amount of light reaching the retina. In optical terms, the pupil is the eye's aperture, while the iris is the diaphragm (optics), diaphragm. Eye color is defined by the iris. Etymology The word "iris" is derived from the Greek word for "rainbow", also Iris (mythology), its goddess plus messenger of the gods in the ''Iliad'', because of the many eye color, colours of this eye part. Structure The iris consists of two layers: the front pigmented Wikt:fibrovascular, fibrovascular layer known as a stroma of iris, stroma and, behind the stroma, pigmented epithelial cells. The stroma is connected to a sphincter muscle (sphincter pupillae), which contracts the pupil in a circular motion, and a set of dilator muscles (dilator pupillae), which pull the iris radially to enlarge the pupil, pulling it in folds. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pancreas
The pancreas (plural pancreases, or pancreata) is an Organ (anatomy), organ of the Digestion, digestive system and endocrine system of vertebrates. In humans, it is located in the abdominal cavity, abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e., it has both an endocrine and a digestive exocrine function. Ninety-nine percent of the pancreas is exocrine and 1% is endocrine. As an endocrine gland, it functions mostly to regulate blood sugar levels, secreting the hormones insulin, glucagon, somatostatin and pancreatic polypeptide. As a part of the digestive system, it functions as an exocrine gland secreting pancreatic juice into the duodenum through the pancreatic duct. This juice contains bicarbonate, which neutralizes acid entering the duodenum from the stomach; and digestive enzymes, which break down carbohydrates, proteins and lipids, fats in food entering the duodenum from the stomach. Inflammation of the pancreas is kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Liver
The liver is a major metabolic organ (anatomy), organ exclusively found in vertebrates, which performs many essential biological Function (biology), functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of various proteins and various other Biochemistry, biochemicals necessary for digestion and growth. In humans, it is located in the quadrants and regions of abdomen, right upper quadrant of the abdomen, below the thoracic diaphragm, diaphragm and mostly shielded by the lower right rib cage. Its other metabolic roles include carbohydrate metabolism, the production of a number of hormones, conversion and storage of nutrients such as glucose and glycogen, and the decomposition of red blood cells. Anatomical and medical terminology often use the prefix List of medical roots, suffixes and prefixes#H, ''hepat-'' from ἡπατο-, from the Greek language, Greek word for liver, such as hepatology, and hepatitis The liver is also an accessory digestive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sphincter Of Oddi
The sphincter of Oddi (SO) (also hepatopancreatic sphincter or Glisson's sphincter), is a sphincter, a muscular valve that, in humans and some animals, controls the flow of bile and pancreatic juice out of the gallbladder and pancreas respectively through the ampulla of Vater into the second part of the duodenum. It is named after Ruggero Oddi. Structure The sphincter of Oddi is a circular muscle band, or sphincter that surrounds the major duodenal papilla. Function The sphincter regulates the secretion of pancreatic juice and bile into the duodenum. It also prevents reflux of duodenal contents into the ampulla of Vater. By preventing reflux of the contents of the duodenum, the sphincter of Oddi prevents the accumulation of particulate matter and sludge in the bile ducts, reducing the risk of cholangitis. The sphincter of Oddi also allows retrograde filling of the gallbladder. The sphincter of Oddi is relaxed by the hormone cholecystokinin via vasoactive intestinal pep ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Large Intestine
The large intestine, also known as the large bowel, is the last part of the gastrointestinal tract and of the Digestion, digestive system in tetrapods. Water is absorbed here and the remaining waste material is stored in the rectum as feces before being removed by defecation. The Colon (anatomy), colon (progressing from the ascending colon to the transverse colon, transverse, the descending colon, descending and finally the sigmoid colon) is the longest portion of the large intestine, and the terms "large intestine" and "colon" are often used interchangeably, but most sources define the large intestine as the combination of the cecum, colon, rectum, and anal canal. Some other sources exclude the anal canal. In humans, the large intestine begins in the right iliac region of the pelvis, just at or below the waist, where it is joined to the end of the small intestine at the cecum, via the ileocecal valve. It then continues as the colon ascending colon, ascending the abdomen, across t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Small Intestine
The small intestine or small bowel is an organ (anatomy), organ in the human gastrointestinal tract, gastrointestinal tract where most of the #Absorption, absorption of nutrients from food takes place. It lies between the stomach and large intestine, and receives bile and pancreatic juice through the pancreatic duct to aid in digestion. The small intestine is about long and folds many times to fit in the abdomen. Although it is longer than the large intestine, it is called the small intestine because it is narrower in diameter. The small intestine has three distinct regions – the duodenum, jejunum, and ileum. The duodenum, the shortest, is where preparation for absorption through small finger-like protrusions called intestinal villus, intestinal villi begins. The jejunum is specialized for the absorption through its lining by enterocytes: small nutrient particles which have been previously digested by enzymes in the duodenum. The main function of the ileum is to absorb vitami ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ileocecal Valve
In many Animalia, including humans, an ileocolic structure or problem is something that concerns the region of the gastrointestinal tract from the ileum to the large intestine, colon. In Animalia that have cecum, ceca, the ileocecal region is a subset of the ileocolic region, and the entire range can also be described as ileocecocolic, whereas in some Animalia, the ileocolic region contains no cecum, as the ileum joins the colon directly. Things that are ileocolic, ileocecal, or both include the following: * Ileocecal fold * Ileocecal/ileocolic intussusception (medical disorder), intussusception * Ileocecal valve * Ileocolic artery * Ileocolic lymph nodes * Ileocolic vein {{SIA, animals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyloric Sphincter
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 language, Greek πυλωρός, via Latin. The word ''pylorus'' in Greek means "gatekeeper", related to "gate" () and is thus linguistically related to the word "pylon (architecture), 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 in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Esophagus
The esophagus (American English), oesophagus (British English), or œsophagus (Œ, archaic spelling) (American and British English spelling differences#ae and oe, see spelling difference) all ; : ((o)e)(œ)sophagi or ((o)e)(œ)sophaguses), colloquially known also as the food pipe, food tube, or gullet, is an Organ (anatomy), organ in vertebrates through which food passes, aided by Peristalsis, peristaltic contractions, from the Human pharynx, pharynx to the stomach. The esophagus is a :wiktionary:fibromuscular, fibromuscular tube, about long in adults, that travels behind the trachea and human heart, heart, passes through the Thoracic diaphragm, diaphragm, and empties into the uppermost region of the stomach. During swallowing, the epiglottis tilts backwards to prevent food from going down the larynx and lungs. The word ''esophagus'' is from Ancient Greek οἰσοφάγος (oisophágos), from οἴσω (oísō), future form of φέρω (phérō, "I carry") + ἔφαγον ( ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acidic
An acid is a molecule or ion capable of either donating a proton (i.e. hydrogen cation, H+), known as a Brønsted–Lowry acid, or forming a covalent bond with an electron pair, known as a Lewis acid. The first category of acids are the proton donors, or Brønsted–Lowry acids. In the special case of aqueous solutions, proton donors form the hydronium ion H3O+ and are known as Arrhenius acids. Brønsted and Lowry generalized the Arrhenius theory to include non-aqueous solvents. A Brønsted–Lowry or Arrhenius acid usually contains a hydrogen atom bonded to a chemical structure that is still energetically favorable after loss of H+. Aqueous Arrhenius acids have characteristic properties that provide a practical description of an acid. Acids form aqueous solutions with a sour taste, can turn blue litmus red, and react with bases and certain metals (like calcium) to form salts. The word ''acid'' is derived from the Latin , meaning 'sour'. An aqueous solution of an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cardia
The stomach is a muscular, hollow organ in the upper gastrointestinal tract of humans and many other animals, including several invertebrates. The Ancient Greek name for the stomach is ''gaster'' which is used as ''gastric'' in medical terms related to the stomach. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach is involved in the gastric phase of digestion, following the cephalic phase in which the sight and smell of food and the act of chewing are stimuli. In the stomach a chemical breakdown of food takes place by means of secreted digestive enzymes and gastric acid. It also plays a role in regulating gut microbiota, influencing digestion and overall health. The stomach is located between the esophagus and the small intestine. The pyloric sphincter controls the passage of partially digested food (chyme) from the stomach into the duodenum, the first and shortest part of the small intestine, where peristalsis takes over ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
