Edisi 31 Download Free Book PDF Kamus Kedokteran Dorland Edisi 31 file at The. Kalo ebook yg bhs indonesia jarang gan emoticon-Malu (S). Get download ebook farmakope indonesia edisi iv PDF file for free from our. Dan Newman, W.A. Kamus Kedokteran Dorland.
![Download Download](https://image.isu.pub/190103131809-a7b4db2714675256e8fed7cccad2a2cb/jpg/page_1_thumb_large.jpg)
The stomach is a muscular, in the of humans and many other animals, including several. The stomach has a dilated structure and functions as a vital organ. In the digestive system the stomach is involved in the second phase of digestion, following (chewing). In humans and many other animals, the stomach is located between the and the. It secretes and to aid in food digestion. The controls the passage of partially digested food from the stomach into the where takes over to move this through the rest of the intestines.
Contents. Structure In humans, the stomach lies between the and the (the first part of the ).
It is in the of the. The top of the stomach lies against the.
Lying behind the stomach is the. A large double fold of visceral called the hangs down from the of the stomach. Two keep the contents of the stomach contained; the (found in the cardiac region), at the junction of the oesophagus and stomach, and the at the junction of the stomach with the duodenum. The stomach is surrounded by (stimulant) and (inhibitor) (networks of and in the gastric, and, celiac and myenteric), which regulate both the secretory activity of the stomach and the motor (motion) activity of its muscles. In adult humans, the stomach has a relaxed, near empty volume of about 75 millilitres.
Because it is a organ, it normally expands to hold about one litre of food. The stomach of a newborn human baby will only be able to retain about 30 millilitres. Sections of the human stomach In classical anatomy the human stomach is divided into four sections, beginning at the cardia, each of which has different cells and functions. The cardia is where the contents of the oesophagus empty into the stomach. The fundus (from, meaning 'bottom') is formed in the upper curved part. The body is the main, central region of the stomach.
The (from, meaning 'gatekeeper') is the lower section of the stomach that empties contents into the. The cardia is defined as the region following the 'z-line' of the gastroesophageal junction, the point at which the changes from to.
Near the cardia is the lower oesophageal sphincter. Recent research has shown that the cardia is not an anatomically distinct region of the stomach but a region of the oesophageal lining damaged by reflux.
Main article: Like the other parts of the gastrointestinal tract, the human stomach walls consist of an outer, inner,. The of the stomach consists of the and the (composed of ), with a thin layer of called the separating it from the submucosa beneath. The lies under the mucosa and consists of, separating the mucosa from the next layer. Is in this layer.
The lies beneath the submucosa and is unique from other organs of the gastrointestinal tract, consisting of three layers:. The inner oblique layer: This layer is responsible for creating the motion that churns and physically breaks down the food. It is the only layer of the three which is not seen in other parts of the.
The antrum has thicker skin cells in its walls and performs more forceful contractions than the fundus. The middle circular layer: At this layer, the is surrounded by a thick circular muscular wall, which is normally tonically constricted, forming a functional (if not anatomically discrete) pyloric, which controls the movement of into the. This layer is concentric to the of the stomach. (AKA myenteric plexus) is found between the outer longitudinal and the middle circular layer and is responsible for the innervation of both (causing and mixing).
The outer longitudinal layer is responsible for moving the bolus towards the pylorus of the stomach through muscular shortening. The stomach also possesses a, consisting of layers of connective tissue continuous with the.
Showing a cross section of the human stomach wall in the body portion of the stomach. In humans, different types of cells are found at the different layers of the. The three types of gland are all located beneath the within the –the of the stomach. The gastric mucosa is pitted with innumerable gastric pits which house the gastric glands. The cardiac glands are found in the cardia of the stomach, enclosing the opening where the esophagus joins to the stomach. Only cardiac glands are found here and they primarily secrete mucus.
They are fewer in number than the other gastric glands and are more shallowly positioned in the mucosa. There are two kinds - either with short ducts or resembling the The fundic glands, are found in the fundus and body of the stomach. They are simple almost straight tubes, two or more of which open into a single duct.
They secrete (HCl). The pyloric glands are located in the antrum of the pylorus. They secrete produced by their. Gene and protein expression. Further information: About 20,000 protein coding genes are expressed in human cells and nearly 70% of these genes are expressed in the normal stomach. Just over 150 of these genes are more specifically expressed in the stomach compared to other organs, with only some 20 genes being highly specific. The corresponding specific proteins expressed in stomach are mainly involved in creating a suitable environment for handling the digestion of food for uptake of nutrients.
Highly stomach-specific proteins include, expressed in the mucosa; and the, expressed in; and gastric and, expressed in. Development In early, the ventral part of the abuts the. During the second week of development, as the embryo grows, it begins to surround parts of the sac. The enveloped portions form the basis for the adult gastrointestinal tract. The sac is surrounded by a network of. Over time, these arteries consolidate into the three main arteries that supply the developing gastrointestinal tract: the,.
The areas supplied by these arteries are used to define the,. The surrounded sac becomes the primitive gut. Sections of this gut begin to differentiate into the organs of the gastrointestinal tract, and the esophagus, and stomach form from the foregut. Function Digestion. See also: In the, a (a small rounded mass of food) enters the stomach through the via the. The stomach releases (protein-digesting such as ) and, which kills or inhibits and provides the acidic of 2 for the to work.
Food is churned by the stomach through muscular contractions of the wall called – reducing the volume of the bolus, before looping around the fundus and the as the boluses are converted into (partially digested food). Chyme slowly passes through the and into the of the, where the extraction of nutrients begins. Depending on the quantity and contents of the meal, the stomach will digest the food into chyme within anywhere between forty minutes and a few hours. The average human stomach can comfortably hold about a litre of food.
Gastric juice in the stomach also contains. Activates this inactive form of enzyme into the active form, pepsin. Pepsin breaks down proteins into polypeptides.
Absorption Although the absorption in the human digestive system is mainly a function of the small intestine, some absorption of certain small molecules nevertheless does occur in the stomach through its lining. This includes:. Water, if the body is.
Medication, such as. 10–20% of ingested (e.g. From alcoholic beverages). To a small extent water-soluble (most are absorbed in the small intestine) The of the human stomach are responsible for producing, which is necessary for the absorption of.
B12 is used in cellular metabolism and is necessary for the production of, and the functioning of the. Control of secretion and motility The movement and the flow of chemicals into the stomach are controlled by both the and by the various of the digestive system: The hormone gastrin causes an increase in the secretion of HCl from the parietal cells, and pepsinogen from chief cells in the stomach. It also causes increased motility in the stomach. Gastrin is released by in the stomach in response to distension of the antrum, and digestive products (especially large quantities of incompletely digested proteins).
It is inhibited by a normally less than 4 (high acid), as well as the hormone. Cholecystokinin (CCK) has most effect on the, causing gall bladder contractions, but it also decreases gastric emptying and increases release of juice which is alkaline and neutralizes the chyme. CCK is synthesized by I-cells in the mucosal epithelium of the small intestine. In a different and rare manner, secretin which has most effects on the pancreas, also diminish acid secretion in the stomach.
Secretin is synthesized by which are located in the duodenal mucosa as well as in the jejunal mucosa in smaller numbers. Gastric inhibitory peptide (GIP) decreases both gastric acid release and motility. GIP is synthesized by K-cells which are located in the duodenal and jejunal mucosa. Enteroglucagon decreases both gastric acid and motility. Other than gastrin, these hormones all act to turn off the stomach action. This is in response to food products in the and gall bladder, which have not yet been absorbed. The stomach needs to push food into the small intestine only when the intestine is not busy.
While the intestine is full and still digesting food, the stomach acts as storage for food. Other Effects of EGF (EGF) results in cellular proliferation, differentiation, and survival. EGF is a low-molecular-weight polypeptide first purified from the mouse submandibular gland, but since then found in many human tissues including the, and the. Salivary EGF, which seems also regulated by dietary inorganic, plays also an important physiological role in the maintenance of oro-oesophageal and gastric tissue integrity. The biological effects of salivary EGF include healing of oral and gastroesophageal ulcers, inhibition of gastric acid secretion, stimulation of DNA synthesis, and mucosal protection from intraluminal injurious factors such as gastric acid, bile acids, pepsin, and trypsin and from physical, chemical, and bacterial agents. Stomach as nutrition sensor The human stomach can 'taste' using glutamate receptors and this information is passed to the and in the as a signal through the. The stomach can also sense, independently of tongue and oral taste receptors,.
This allows the brain to link value of foods to their tastes. Clinical significance.
Main article: A can be used to examine the stomach for various disorders. This will often include the use of a. Another method of examination of the stomach, is the use of an.
A is considered the gold standard to assess gastric emptying rate. A large number of studies have indicated that most cases of, and, in humans are caused by infection, and an association has been seen with the development of stomach cancer. A is actually noise from the intestines. The stomach has to regenerate a new layer of mucus every two weeks, or else damage to the may result.
Surgery In humans, many procedures involve the stomach, in order to lose weight. A may be placed around the cardia area, which can adjust to limit intake. The, or the stomach may be. Surgical removal of the stomach is called a, and removal of the cardia area is a called a cardiectomy. 'Cardiectomy' is a term that is also used to describe the removal of the. A gastrectomy may be carried out because of gastric cancer or severe perforation of the stomach wall. History There were previously conflicting statements in the academic anatomy community over whether the cardia is part of the stomach, part of the oesophagus or a distinct entity.
Modern surgical and medical textbooks have agreed that 'The gastric cardia is now clearly considered to be part of the stomach.' Etymology The word stomach is derived from the stomachus which is derived from the word stomachos ( στόμαχος), ultimately from stoma ( στόμα), 'mouth'. The words gastro- and gastric (meaning related to the stomach) are both derived from the Greek word gaster ( γαστήρ, meaning 'belly' ). Other animals.
Comparison of stomach glandular regions from several mammalian species. Frequency of glands may vary more smoothly between regions than is diagrammed here.
Asterisk (ruminant) represents the omasum, which is absent in (Tylopoda also has some cardiac glands opening onto ventral and ) Many other variations exist among the mammals. Yellow Green Purple Red Blue Dark blue Although the precise shape and size of the stomach varies widely among different vertebrates, the relative positions of the oesophageal and duodenal openings remain relatively constant.
As a result, the organ always curves somewhat to the left before curving back to meet the pyloric sphincter. However, and some fish have no stomach at all, with the oesophagus opening directly into the anus.
These animals all consume diets that either require little storage of food, or no pre-digestion with gastric juices, or both. The gastric lining is usually divided into two regions, an anterior portion lined by fundic glands, and a posterior with pyloric glands.
Cardiac glands are unique to, and even then are absent in a number of species. The distributions of these glands vary between species, and do not always correspond with the same regions as in humans. Furthermore, in many non-human mammals, a portion of the stomach anterior to the cardiac glands is lined with epithelium essentially identical to that of the oesophagus., in particular, have a complex stomach, the first three chambers of which are all lined with oesophageal mucosa. In and, the stomach is divided into two regions.
Anteriorly is a narrow tubular region, the, lined by fundic glands, and connecting the true stomach to the. Beyond lies the powerful muscular, lined by pyloric glands, and, in some species, containing stones that the animal swallows to help grind up food. In there is also a crop.
The insect stomach is called the. Information about the stomach in or can be found under the respective articles. Additional images.