Misplaced Pages

#528471

106-471: Vomiting (also known as emesis , puking and throwing up ) is the involuntary, forceful expulsion of the contents of one's stomach through the mouth and sometimes the nose . Vomiting can be the result of ailments like food poisoning , gastroenteritis , pregnancy , motion sickness , or hangover; or it can be an after effect of diseases such as brain tumors , elevated intracranial pressure , or overexposure to ionizing radiation . The feeling that one

212-432: A chemoreceptor trigger zone , known as the area postrema , stimulation of which can lead to vomiting. The area postrema is a circumventricular organ and as such lies outside the blood–brain barrier ; it can therefore be stimulated by blood-borne drugs that can stimulate vomiting or inhibit it . There are various sources of input to the vomiting center: The vomiting act encompasses three types of outputs initiated by

318-401: A lamina propria , and a thin layer of smooth muscle called the muscularis mucosa . Beneath the mucosa lies the submucosa , consisting of fibrous connective tissue . Meissner's plexus is in this layer interior to the oblique muscle layer. Outside of the submucosa lies the muscular layer. It consists of three layers of muscular fibres, with fibres lying at angles to each other. These are

424-502: A concerted action or 'sympathy' of the organs. Little changed until the Renaissance when Bartolomeo Eustacheo (1545) depicted the sympathetic nerves, the vagus and adrenal glands in anatomical drawings. Jacobus Winslow (1669–1760), a Danish-born professor working in Paris, popularised the term 'sympathetic nervous system' in 1732 to describe the chain of ganglia and nerves which were connected to

530-449: A form of mass hysteria . Most people try to contain their vomit by vomiting into a sink, toilet, or trash can, as vomit is difficult and unpleasant to clean. On airplanes and boats, special bags are supplied for sick passengers to vomit into. A special disposable bag (leakproof, puncture-resistant, odorless) containing absorbent material that solidifies the vomit quickly is also available, making it convenient and safe to store until there

636-410: A high triglyceride content remain in the stomach the longest. Since enzymes in the small intestine digest fats slowly, food can stay in the stomach for 6 hours or longer when the duodenum is processing fatty chyme. However, this is still a fraction of the 24 to 72 hours that full digestion typically takes from start to finish. Although the absorption in the human digestive system is mainly a function of

742-430: A process called gastric emptying , rhythmic mixing waves force about 3 mL of chyme at a time through the pyloric sphincter and into the duodenum. Release of a greater amount of chyme at one time would overwhelm the capacity of the small intestine to handle it. The rest of the chyme is pushed back into the body of the stomach, where it continues mixing. This process is repeated when the next mixing waves force more chyme into

848-417: A range of viruses and bacteria): Psychiatric/behavioral: An emetic , such as syrup of ipecac , is a substance that induces vomiting when administered orally or by injection. An emetic is used medically when a substance has been ingested and must be expelled from the body immediately. For this reason, many toxic and easily digestible products such as rat poison contain an emetic. This presents no problem for

954-442: Is a narrow tubular region, the proventriculus , lined by fundic glands, and connecting the true stomach to the crop . Beyond lies the powerful muscular gizzard , lined by pyloric glands, and, in some species, containing stones that the animal swallows to help grind up food. In insects , there is also a crop. The insect stomach is called the midgut . Information about the stomach in echinoderms or molluscs can be found under

1060-404: Is a precursor to pepsin- the highly acidic environment converts the pepsinogen to pepsin), and neuroendocrine cells that secrete serotonin . Glands differ where the stomach meets the esophagus and near the pylorus. Near the gastroesophageal junction lie cardiac glands , which primarily secrete mucus. They are fewer in number than the other gastric glands and are more shallowly positioned in

1166-551: Is a stimulated condition of the sympathetic nervous system, marked by vascular spasm elevated blood pressure , and goose bumps . Heightened sympathetic nervous system activity is also linked to various mental health disorders such as, anxiety disorders and post-traumatic stress disorder (PTSD). It is suggested that the overactivation of the SNS results in the increased severity of PTSD symptoms. In accordance with disorders like hypertension and cardiovascular disease mentioned above, PTSD

SECTION 10

#1733094272529

1272-519: Is a term that is also used to describe the removal of the heart . A gastrectomy may be carried out because of gastric cancer or severe perforation of the stomach wall. Fundoplication is stomach surgery in which the fundus is wrapped around the lower esophagus and stitched into place. It is used to treat gastroesophageal reflux disease (GERD) . The word stomach is derived from Greek stomachos ( στόμαχος ), ultimately from stoma ( στόμα ) 'mouth'. Gastro- and gastric (meaning 'related to

1378-504: Is a useful rule of thumb. It was originally believed that the sympathetic nervous system arose with jawed vertebrates . However, the sea lamprey ( Petromyzon marinus ), a jawless vertebrate , has been found to contain the key building blocks and developmental controls of a sympathetic nervous system. Nature described this research as a "landmark study" that "point to a remarkable diversification of sympathetic neuron populations among vertebrate classes and species". The dysfunction of

1484-418: Is about to vomit is called nausea ; it often precedes, but does not always lead to vomiting. Impairment due to alcohol or anesthesia can cause inhalation of vomit. In severe cases, where dehydration develops, intravenous fluid may be required. Antiemetics are sometimes necessary to suppress nausea and vomiting. Self-induced vomiting can be a component of an eating disorder such as bulimia nervosa , and

1590-544: Is also linked with the increased risk of developing mentioned diseases, further correlating the link between these disorders and the SNS. The sympathetic nervous system is sensitive to stress, studies suggest that the chronic dysfunction of the sympathetic system results in migraines, due to the vascular changes associated with tension headaches. Individuals with migraine attacks are exhibited to have symptoms that are associated with sympathetic dysfunction, which include reduced levels of plasma norepinephrine levels, sensitivity of

1696-542: Is an acidic fluid containing hydrochloric acid and digestive enzymes. The glands contains a number of cells, with the function of the glands changing depending on their position within the stomach. Within the body and fundus of the stomach lie the fundic glands . In general, these glands are lined by column-shaped cells that secrete a protective layer of mucus and bicarbonate . Additional cells present include parietal cells that secrete hydrochloric acid and intrinsic factor , chief cells that secrete pepsinogen (this

1802-447: Is an indirect result of the kidney compensating for the loss of acid. With the loss of intake of food the individual may eventually become cachectic . A less frequent occurrence results from a vomiting of intestinal contents, including bile acids and HCO 3 . Repeated or profuse vomiting may cause erosions to the esophagus or small tears in the esophageal mucosa ( Mallory–Weiss tear ). This may become apparent if fresh red blood

1908-509: Is an opportunity to dispose of it conveniently. People who vomit chronically (e.g., as part of an eating disorder such as bulimia nervosa ) may devise various ways to hide this disorder. An online study of people's responses to "horrible sounds" found vomiting "the most disgusting". Professor Trevor Cox of the University of Salford 's Acoustic Research Centre said, "We are pre-programmed to be repulsed by horrible things such as vomiting, as it

2014-525: Is from the celiac trunk , and venous drainage is by the portal venous system . Lymph from these organs is drained to the prevertebral celiac nodes at the origin of the celiac artery from the aorta . In the human digestive system , a bolus (a small rounded mass of chewed up food) enters the stomach through the esophagus via the lower esophageal sphincter . The stomach releases proteases (protein-digesting enzymes such as pepsin ), and hydrochloric acid , which kills or inhibits bacteria and provides

2120-412: Is fundamental to staying alive to avoid nasty stuff." It is thought that disgust is triggered by the sound of vomiting to protect those nearby from possibly diseased food. Emetophilia is sexual arousal from vomiting, or watching others vomit. Emetophobia is a phobia that causes overwhelming, intense anxiety pertaining to vomiting. Stomach The stomach is located between the esophagus and

2226-447: Is in response to food products in the liver 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. Epidermal growth factor (EGF) results in cellular proliferation, differentiation, and survival. EGF is a low-molecular-weight polypeptide first purified from

SECTION 20

#1733094272529

2332-414: Is in the left upper quadrant of the abdominal cavity . The top of the stomach lies against the diaphragm . Lying behind the stomach is the pancreas . A large double fold of visceral peritoneum called the greater omentum hangs down from the greater curvature of the stomach. Two sphincters keep the contents of the stomach contained; the lower esophageal sphincter (found in the cardiac region), at

2438-527: Is itself now classified as an eating disorder on its own, purging disorder . Vomiting is dangerous if gastric content enters the respiratory tract . Under normal circumstances the gag reflex and coughing prevent this from occurring; however, these protective reflexes are compromised in persons who are under the influence of certain substances (including alcohol ) or even mildly anesthetized . The individual may choke and asphyxiate or develop aspiration pneumonia . Prolonged and excessive vomiting depletes

2544-402: Is mixed with vomit after several episodes. Recurrent vomiting, such as observed in bulimia nervosa or more rarely anorexia nervosa , may lead to the destruction of the tooth enamel due to the acidity of the vomit. Digestive enzymes can also have a negative effect on oral health, by degrading the tissue of the gums . Receptors on the floor of the fourth ventricle of the brain represent

2650-434: Is passed to the lateral hypothalamus and limbic system in the brain as a palatability signal through the vagus nerve . The stomach can also sense, independently of tongue and oral taste receptors, glucose , carbohydrates , proteins , and fats . This allows the brain to link nutritional value of foods to their tastes. This syndrome defines the association between thyroid disease and chronic gastritis, which

2756-407: Is supplied by the right gastric artery inferiorly and the left gastric artery superiorly, which also supplies the cardiac region. The greater curvature is supplied by the right gastroepiploic artery inferiorly and the left gastroepiploic artery superiorly. The fundus of the stomach, and also the upper portion of the greater curvature, is supplied by the short gastric arteries , which arise from

2862-422: Is termed hematemesis ("blood vomiting"). Altered blood bears resemblance to coffee grounds (as the iron in the blood is oxidized ) and, when this matter is identified, the term coffee-ground vomiting is used. Bile can enter the vomit during subsequent heaves due to duodenal contraction if the vomiting is severe. Fecal vomiting is often a consequence of intestinal obstruction or a gastrocolic fistula and

2968-405: Is treated as a warning sign of this potentially serious problem ( signum mali ominis ). If the vomiting reflex continues for an extended period with no appreciable vomitus, the condition is known as non-productive emesis or "dry heaves", which can be painful and debilitating. Vomiting may be due to a large number of causes, and protracted vomiting has a long differential diagnosis . Causes in

3074-482: Is used as an emetic in veterinary practice. An antiemetic is a drug that is effective against vomiting and nausea . Antiemetics are typically used to treat motion sickness and the side effects of medications such as opioids and chemotherapy . Antiemetics act by inhibiting the receptor sites associated with emesis. Hence, anticholinergics, antihistamines, dopamine antagonists, serotonin antagonists, and cannabinoids are used as antiemetics. Evidence to support

3180-468: The Greeks , notes that to vomit in the presence of others is prohibited among Persians. It is quite common that, when one person vomits, others nearby become nauseated, particularly when smelling the vomit of others, and often to the point of vomiting themselves. It is believed that this is an evolved trait among primates . Many primates in the wild tend to browse for food in small groups. Should one member of

3286-426: The digestive tract Causes in the sensory system : Causes in the brain : Metabolic disturbances (these may irritate both the stomach and the parts of the brain that coordinate vomiting): Pregnancy : Drug reaction (vomiting may occur as an acute somatic response to): High altitude : Illness (sometimes colloquially known as " stomach flu "—a broad name that refers to gastric inflammation caused by

Vomiting - Misplaced Pages Continue

3392-419: The large intestine ; constrict blood vessels; increase peristalsis in the oesophagus ; cause pupillary dilation , piloerection ( goose bumps ) and perspiration ( sweating ); and raise blood pressure. One exception is with certain blood vessels, such as those in the cerebral and coronary arteries, which dilate (rather than constrict) with increased sympathetic tone. This is because of a proportional increase in

3498-414: The nervous system . Chyme from the stomach is slowly released into the duodenum through coordinated peristalsis and opening of the pyloric sphincter. The movement and the flow of chemicals into the stomach are controlled by both the autonomic nervous system and by the various digestive hormones of the digestive system: Other than gastrin, these hormones all act to turn off the stomach action. This

3604-473: The preganglionic sympathetic fibers that end in the adrenal medulla (but also all other sympathetic fibers) secrete acetylcholine, which activates the great secretion of adrenaline (epinephrine) and to a lesser extent noradrenaline (norepinephrine) from it. Therefore, this response that acts primarily on the cardiovascular system is mediated directly via impulses transmitted through the sympathetic nervous system and indirectly via catecholamines secreted from

3710-416: 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 to move this through the rest of the intestines. In the human digestive system , the stomach lies between the esophagus and the duodenum (the first part of the small intestine ). It

3816-484: The tail of the pancreas , splenic artery , left kidney , left suprarenal gland , transverse colon and its mesocolon , and the left crus of diaphragm , and the left colic flexure . The term was introduced around 1896 by Philip Polson of the Catholic University School of Medicine, Dublin. However this was brought into disrepute by surgeon anatomist J Massey. The lesser curvature of the human stomach

3922-465: The 18th century, Jacob B. Winslow applied the term specifically to nerves. The concept that an independent part of the nervous system coordinates body functions had its origin in the works of Galen (129–199), who proposed that nerves distributed spirits throughout the body. From animal dissections he concluded that there were extensive interconnections from the spinal cord to the viscera and from one organ to another. He proposed that this system fostered

4028-472: The CNS masked as referred pain . If the peritoneal cavity becomes inflamed or if the bowel is suddenly distended, the body will interpret the afferent pain stimulus as somatic in origin. This pain is usually non-localized. The pain is also usually referred to dermatomes that are at the same spinal nerve level as the visceral afferent synapse . Together with the other component of the autonomic nervous system ,

4134-425: The SNS activity does not only apply to insomnia, but also with various disorders previously discussed. However, overtime with advancements in technology and techniques in research studies the disruption of the SNS and its impact on the human body will be explored further. The name of this system can be traced to the concept of sympathy , in the sense of "connection between parts", first used medically by Galen . In

4240-400: The SNS innervate tissues in almost every organ system, providing at least some regulation of functions as diverse as pupil diameter, gut motility , and urinary system output and function. It is perhaps best known for mediating the neuronal and hormonal stress response commonly known as the fight-or-flight response . This response is also known as sympatho-adrenal response of the body, as

4346-409: The acidic pH of 2 for the proteases to work. Food is churned by the stomach through peristaltic muscular contractions of the wall – reducing the volume of the bolus, before looping around the fundus and the body of stomach as the boluses are converted into chyme (partially digested food). Chyme slowly passes through the pyloric sphincter and into the duodenum of the small intestine , where

Vomiting - Misplaced Pages Continue

4452-407: The adrenal medulla. The sympathetic nervous system is responsible for priming the body for action, particularly in situations threatening survival. One example of this priming is in the moments before waking, in which sympathetic outflow spontaneously increases in preparation for action. Sympathetic nervous system stimulation causes vasoconstriction of most blood vessels, including many of those in

4558-415: The autonomic nervous system, and sometimes considered an independent system. The autonomic nervous system functions to regulate the body's unconscious actions. The sympathetic nervous system's primary process is to stimulate the body's fight or flight response . It is, however, constantly active at a basic level to maintain homeostasis . The sympathetic nervous system is described as being antagonistic to

4664-507: The axon enters the paravertebral ganglion at the level of its originating spinal nerve. After this, it can then either synapse in this ganglion, ascend to a more superior or descend to a more inferior paravertebral ganglion and synapse there, or it can descend to a prevertebral ganglion and synapse there with the postsynaptic cell. The postsynaptic cell then goes on to innervate the targeted end effector (i.e. gland, smooth muscle, etc.). Because paravertebral and prevertebral ganglia are close to

4770-486: The axons link across a space, the synapse , to the dendrites of the second cell. The first cell (the presynaptic cell) sends a neurotransmitter across the synaptic cleft, where it activates the second cell (the postsynaptic cell). The message is then carried to the final destination. Presynaptic nerves' axons terminate in either the paravertebral ganglia or prevertebral ganglia . There are four different paths an axon can take before reaching its terminal. In all cases,

4876-445: The basis for the adult gastrointestinal tract. The sac is surrounded by a network of vitelline arteries and veins . Over time, these arteries consolidate into the three main arteries that supply the developing gastrointestinal tract: the celiac artery , superior mesenteric artery , and inferior mesenteric artery . The areas supplied by these arteries are used to define the foregut , midgut , and hindgut . The surrounded sac becomes

4982-417: The body of water ( dehydration ), and may alter the electrolyte status. Gastric vomiting leads to the loss of acid (protons) and chloride directly. Combined with the resulting alkaline tide , this leads to hypochloremic metabolic alkalosis (low chloride levels together with high HCO 3 and CO 2 and increased blood pH ) and often hypokalemia ( potassium depletion). The hypokalemia

5088-613: The body, this over-activation includes the hyperactivity of the SNS. Whereby during sleep cycle disruption sympathetic baroreflex function and neural cardiovascular responses become impaired. However more research is still required, as methods used in measuring SNS biological measures are not so reliable due to the sensitivity of the SNS, many factors easily effect its activity, like stress, environment, timing of day, and disease. These factors can impact results significantly and for more accurate results extremely invasive methods are required, such as microneurography. The difficultly of measuring

5194-416: The body. At the synapses within the ganglia, preganglionic neurons release acetylcholine , a neurotransmitter that activates nicotinic acetylcholine receptors on postganglionic neurons. In response to this stimulus, the postganglionic neurons release norepinephrine , which activates adrenergic receptors that are present on the peripheral target tissues. The activation of target tissue receptors causes

5300-400: The cardia followed by the fundus, the body and the pylorus. The cardia is defined as the region following the "z-line" of the gastroesophageal junction , the point at which the epithelium changes from stratified squamous to columnar . Near the cardia is the lower esophageal sphincter. The stomach bed refers to the structures upon which the stomach rests in mammals. These include

5406-542: The central nervous system (or CNS), are not divided into parasympathetic and sympathetic fibers as the efferent fibers are. Instead, autonomic sensory information is conducted by general visceral afferent fibers . General visceral afferent sensations are mostly unconscious visceral motor reflex sensations from hollow organs and glands that are transmitted to the CNS . While the unconscious reflex arcs normally are undetectable, in certain instances they may send pain sensations to

SECTION 50

#1733094272529

5512-497: The chemoreceptor trigger zone: Motor, parasympathetic nervous system (PNS), and sympathetic nervous system (SNS). They are as follows: The vomiting act has two phases. In the retching phase , the abdominal muscles undergo a few rounds of coordinated contractions together with the diaphragm and the muscles used in respiratory inspiration. For this reason, an individual may confuse this phase with an episode of violent hiccups . In this retching phase, nothing has yet been expelled. In

5618-457: The consistent emetic effects of ayahuasca—in addition to its many other therapeutic properties—was of medicinal benefit to indigenous peoples of the Amazon , in helping to clear parasites from the gastrointestinal system. There have also been documented cases of a single ill and vomiting individual inadvertently causing others to vomit, when they are especially fearful of also becoming ill, through

5724-439: The digesting and readsorbing ability, and lastly, similar ability to form iodotyrosines by peroxidase activity, where iodide acts as an electron donor in the presence of H 2 O 2 . In the following years, many researchers published reviews about this syndrome. A series of radiographs can be used to examine the stomach for various disorders. This will often include the use of a barium swallow . Another method of examination of

5830-426: The disorder. The sympathetic nervous system holds a major role in long-term regulation of hypertension, whereby the central nervous system stimulates sympathetic nerve activity in specific target organs or tissues via neurohumoral signals. In terms of hypertension, the overactivation of the sympathetic system results in vasoconstriction and increased heart rate resulting in increased blood pressure. In turn, increasing

5936-464: The dorsal mesentery thins and forms the greater omentum , which is attached to the greater curvature of the stomach. The ventral mesentery forms the lesser omentum, and is attached to the developing liver . In the adult, these connective structures of omentum and mesentery form the peritoneum , and act as an insulating and protective layer while also supplying organs with blood and lymph vessels as well as nerves. Arterial supply to all these structures

6042-411: The duodenum. Gastric emptying is regulated by both the stomach and the duodenum. The presence of chyme in the duodenum activates receptors that inhibit gastric secretion. This prevents additional chyme from being released by the stomach before the duodenum is ready to process it. The fundus stores both undigested food and gases that are released during the process of chemical digestion. Food may sit in

6148-416: The effectiveness of the rodenticide as rodents are unable to vomit. Inducing vomiting can remove the substance before it is absorbed into the body. Emetics can be divided into two categories, those which produce their effect by acting on the vomiting center in the medulla, and those which act directly on the stomach itself. Some emetics, such as ipecac, fall into both categories; they initially act directly on

6254-399: The effects associated with the sympathetic system. However, there are three important exceptions: Sympathetic nerves arise from near the middle of the spinal cord in the intermediolateral nucleus of the lateral grey column , beginning at the first thoracic vertebra of the vertebral column and are thought to extend to the second or third lumbar vertebra. Because its cells begin in

6360-497: The esophagus opening directly into the intestine. These animals all consume diets that require little storage of food, no predigestion with gastric juices, or both. The gastric lining is usually divided into two regions, an anterior portion lined by fundic glands and a posterior portion lined with pyloric glands. Cardiac glands are unique to mammals , and even then are absent in a number of species. The distributions of these glands vary between species, and do not always correspond with

6466-413: The expulsion of gastric contents. As the mouth and nasal cavity are connected via the back of the throat, particularly forceful vomiting, or producing large quantities of vomit may result in material being ejected through the nostrils in addition to the mouth. Individuals who do not regularly exercise their abdominal muscles may experience pain in those muscles for a few days. The decrease in pressure and

SECTION 60

#1733094272529

6572-429: The extraction of nutrients begins. Gastric juice in the stomach also contains pepsinogen . Hydrochloric acid activates this inactive form of enzyme into the active form, pepsin. Pepsin breaks down proteins into polypeptides . Within a few moments after food enters the stomach, mixing waves begin to occur at intervals of approximately 20 seconds. A mixing wave is a unique type of peristalsis that mixes and softens

6678-418: The food with gastric juices to create chyme. The initial mixing waves are relatively gentle, but these are followed by more intense waves, starting at the body of the stomach and increasing in force as they reach the pylorus. The pylorus, which holds around 30 mL of chyme, acts as a filter, permitting only liquids and small food particles to pass through the mostly, but not fully, closed pyloric sphincter . In

6784-501: The fundus of the stomach for a while before being mixed with the chyme. While the food is in the fundus, the digestive activities of salivary amylase continue until the food begins mixing with the acidic chyme. Ultimately, mixing waves incorporate this food with the chyme, the acidity of which inactivates salivary amylase and activates lingual lipase . Lingual lipase then begins breaking down triglycerides into free fatty acids, and mono- and diglycerides. The breakdown of protein begins in

6890-417: The head and thorax organs, and the celiac and mesenteric ganglia , which send sympathetic fibers to the gut. Messages travel through the sympathetic nervous system in a bi-directional flow. Efferent messages can simultaneously trigger changes in different body parts. For example, the sympathetic nervous system can accelerate heart rate ; widen bronchial passages; decrease motility (movement) of

6996-406: The inner oblique, middle circular, and outer longitudinal layers. The presence of the inner oblique layer is distinct from other parts of the gastrointestinal tract, which do not possess this layer. The stomach contains the thickest muscular layer consisting of three layers, thus maximum peristalsis occurs here. The outer longitudinal layer is responsible for moving the semi-digested food towards

7102-424: The intestines. In humans, many bariatric surgery procedures involve the stomach, in order to lose weight. A gastric band may be placed around the cardia area, which can adjust to limit intake. The anatomy of the stomach may be modified , or the stomach may be bypassed entirely . Surgical removal of the stomach is called a gastrectomy , and removal of the cardia area is a called a cardiectomy . "Cardiectomy"

7208-400: The junction of the esophagus and stomach, and the pyloric sphincter at the junction of the stomach with the duodenum. The stomach is surrounded by parasympathetic (inhibitor) and sympathetic (stimulant) plexuses (networks of blood vessels and nerves in the anterior gastric, posterior , superior and inferior , celiac and myenteric), which regulate both the secretory activity of

7314-404: The lungs, and the brain during a sympathoadrenal response. The net effect of this is a shunting of blood away from the organs not necessary to the immediate survival of the organism and an increase in blood flow to those organs involved in intense physical activity. The afferent fibers of the autonomic nervous system , which transmit sensory information from the internal organs of the body back to

7420-738: The mouse submandibular gland, but since then found in many human tissues including the submandibular gland , and the parotid gland . Salivary EGF, which also seems to be regulated by dietary inorganic iodine , also plays an important physiological role in the maintenance of oro-esophageal 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. The human stomach has receptors responsive to sodium glutamate and this information

7526-414: The mucosa. There are two kinds - either simple tubular glands with short ducts or compound racemose resembling the duodenal Brunner's glands . Near the pylorus lie pyloric glands located in the antrum of the pylorus. They secrete mucus, as well as gastrin produced by their G cells . About 20,000 protein-coding genes are expressed in human cells and nearly 70% of these genes are expressed in

7632-416: The mucosa; pepsinogen and gastric lipase , expressed in gastric chief cells ; and a gastric ATPase and gastric intrinsic factor , expressed in parietal cells . In the early part of the development of the human embryo , the ventral part of the embryo abuts the yolk sac . During the third week of development, as the embryo grows, it begins to surround parts of the yolk sac. The enveloped portions form

7738-426: The next phase, also termed the expulsive phase , intense pressure is formed in the stomach brought about by enormous shifts in both the diaphragm and the abdomen. These shifts are, in essence, vigorous contractions of these muscles that last for extended periods of time—much longer than a normal period of muscular contraction. The pressure is then suddenly released when the upper esophageal sphincter relaxes resulting in

7844-411: 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 gastrokine-1 expressed in

7950-470: The parasympathetic nervous system, the sympathetic nervous system aids in the control of most of the body's internal organs. Reaction to stress —as in the flight-or-fight response—is thought to be elicited by the sympathetic nervous system and to counteract the parasympathetic system , which works to promote maintenance of the body at rest. The comprehensive functions of both the parasympathetic and sympathetic nervous systems are not so straightforward, but this

8056-535: The parasympathetic nervous system. The latter stimulates the body to "feed and breed" and to (then) "rest-and-digest". The SNS has a major role in various physiological processes such as blood glucose levels, body temperature, cardiac output, and immune system function. The formation of sympathetic neurons being observed at embryonic stage of life and its development during aging shows its significance in health; its dysfunction has shown to be linked to various health disorders. There are two kinds of neurons involved in

8162-401: The party react adversely to some ingested food, it may be advantageous (in a survival sense) for other members of the party to also vomit. This tendency in human populations has been observed at drinking parties, where excessive consumption of alcoholic beverages may cause a number of party members to vomit nearly simultaneously, this being triggered by the initial vomiting of a single member of

8268-449: The party. This phenomenon has been touched on in popular culture: notorious instances appear in the films Monty Python's The Meaning of Life (1983) and Stand by Me (1986). Intense vomiting in ayahuasca ceremonies is a common phenomenon. However, people who experience "la purga" after drinking ayahuasca, in general, regard the practise as both a physical and spiritual cleanse and often come to welcome it. It has been suggested that

8374-425: The peripheral adrenergic receptors. Insomnia is a sleeping disorder, that makes falling or staying asleep difficult, this disruption in sleep results in sleep deprivation and various symptoms, with the severity depending on whether the insomnia is acute or chronic. The most favoured hypothesis for the cause of insomnia is the hyperarousal hypothesis, which is known as a collective over-activation of various systems in

8480-429: The potential of the development of cardiovascular disease. In heart failure , the sympathetic nervous system increases its activity, leading to increased force of muscular contractions that in turn increases the stroke volume , as well as peripheral vasoconstriction to maintain blood pressure . However, these effects accelerate disease progression, eventually increasing mortality in heart failure. Sympathicotonia

8586-426: The preganglionic cells of the sympathetic nervous system are located between the first thoracic segment and the third lumbar segments of the spinal cord. Postganglionic cells have their cell bodies in the ganglia and send their axons to target organs or glands. The ganglia include not just the sympathetic trunks but also the cervical ganglia ( superior , middle and inferior ), which send sympathetic nerve fibers to

8692-487: The presence of β 2 adrenergic receptors rather than α 1 receptors. β 2 receptors promote vessel dilation instead of constriction like α1 receptors. An alternative explanation is that the primary (and direct) effect of sympathetic stimulation on coronary arteries is vasoconstriction followed by a secondary vasodilation caused by the release of vasodilatory metabolites due to the sympathetically increased cardiac inotropy and heart rate. This secondary vasodilation caused by

8798-411: The presynaptic neuron, they will release their neurotransmitter (epinephrine) directly into the bloodstream. In the sympathetic nervous system and other peripheral nervous system components, these synapses are made at sites called ganglia. The cell that sends its fiber is called a preganglionic cell, while the cell whose fiber leaves the ganglion is called a postganglionic cell. As mentioned previously,

8904-441: The primary vasoconstriction is termed functional sympatholysis, the overall effect of which on coronary arteries is dilation. The target synapse of the postganglionic neuron is mediated by adrenergic receptors and is activated by either norepinephrine (noradrenaline) or epinephrine (adrenaline). The sympathetic nervous system is responsible for up- and down-regulating many homeostatic mechanisms in living organisms. Fibers from

9010-433: 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. As the stomach rotates during early development, the dorsal and ventral mesentery rotate with it; this rotation produces a space anterior to the expanding stomach called the greater sac, and a space posterior to the stomach called the lesser sac. After this rotation

9116-504: The pylorus of the stomach through muscular shortening. To the outside of the muscular layer lies a serosa , consisting of layers of connective tissue continuous with the peritoneum . Smooth mucosa along the inside of the lesser curvature forms a passageway - the gastric canal that fast-tracks liquids entering the stomach, to the pylorus. The mucosa lining the stomach is lined with gastric pits , which receive gastric juice , secreted by between 2 and 7 gastric glands . Gastric juice

9222-400: The release of endorphins into the bloodstream after the expulsion causes the vomiter to feel relief almost immediately after vomiting. Gastric secretions and likewise vomit are highly acidic . Recent food intake appears in the gastric vomit. Irrespective of the content, vomit tends to be malodorous . The content of the vomitus (vomit) may be of medical interest. Fresh blood in the vomit

9328-420: The respective articles. Sympathetic nervous system The sympathetic nervous system ( SNS or SANS , sympathetic autonomic nervous system, to differentiate it from the somatic nervous system ) is one of the three divisions of the autonomic nervous system , the others being the parasympathetic nervous system and the enteric nervous system . The enteric nervous system is sometimes considered part of

9434-468: The retraction of sympathetic neurons due to leptin resistance, which is linked to obesity. Another example, although more research is required, is the observed link that diabetes results in the impairment of synaptic transmission due to the inhibition of acetylcholine receptors as a result of high blood glucose levels. The loss of sympathetic neurons is also associated with the reduction of insulin secretion and impaired glucose tolerance, further exacerbating

9540-409: 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 esophagus. Ruminants , in particular, have a complex stomach, the first three chambers of which are all lined with esophageal mucosa. In birds and crocodilians , the stomach is divided into two regions. Anteriorly

9646-442: The shiny white sheaths of myelin around each axon) that connect to either the paravertebral (which lie near the vertebral column) or prevertebral (which lie near the aortic bifurcation) ganglia extending alongside the spinal column. To reach target organs and glands, the axons must travel long distances in the body, and, to accomplish this, many axons relay their message to a second cell through synaptic transmission . The ends of

9752-406: The skin, the digestive tract, and the kidneys. This occurs due to the activation of alpha-1 adrenergic receptors by norepinephrine released by post-ganglionic sympathetic neurons. These receptors exist throughout the vasculature of the body but are inhibited and counterbalanced by beta-2 adrenergic receptors (stimulated by epinephrine release from the adrenal glands) in the skeletal muscles, the heart,

9858-449: The small intestine, some absorption of certain small molecules nevertheless does occur in the stomach through its lining. This includes: The parietal cells of the human stomach are responsible for producing intrinsic factor , which is necessary for the absorption of vitamin B12 . B12 is used in cellular metabolism and is necessary for the production of red blood cells , and the functioning of

9964-526: The spinal cord, presynaptic neurons are much shorter than their postsynaptic counterparts, which must extend throughout the body to reach their destinations. A notable exception to the routes mentioned above is the sympathetic innervation of the suprarenal (adrenal) medulla. In this case, presynaptic neurons pass through paravertebral ganglia, on through prevertebral ganglia and then synapse directly with suprarenal tissue. This tissue consists of cells that have pseudo-neuron like qualities in that when activated by

10070-442: The splenic artery. The two sets of gastric lymph nodes drain the stomach. Like the other parts of the gastrointestinal wall , the human stomach wall from inner to outer, consists of a mucosa , submucosa , muscular layer , subserosa and serosa . The inner part of the stomach wall is the gastric mucosa a mucous membrane that forms the lining of the stomach. the membrane consists of an outer layer of columnar epithelium ,

10176-449: The stomach and the motor (motion) activity of its muscles. The stomach is distensible , and can normally expand to hold about one litre of food. In a newborn human baby the stomach will only be able to hold about 30 millilitres. The maximum stomach volume in adults is between 2 and 4 litres, although volumes of up to 15 litres have been observed in extreme circumstances. The human stomach can be divided into four sections, beginning at

10282-432: The stomach through the actions of hydrochloric acid, and the enzyme pepsin . The stomach can also produce gastric lipase , which can help digesting fat. The contents of the stomach are completely emptied into the duodenum within two to four hours after the meal is eaten. Different types of food take different amounts of time to process. Foods heavy in carbohydrates empty fastest, followed by high-protein foods. Meals with

10388-484: The stomach') are both derived from Greek gaster ( γαστήρ ) 'belly'. Although the precise shape and size of the stomach varies widely among different vertebrates, the relative positions of the esophageal 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, lampreys , hagfishes , chimaeras , lungfishes , and some teleost fish have no stomach at all, with

10494-414: The stomach, is the use of an endoscope . A gastric emptying study is considered the gold standard to assess the gastric emptying rate. A large number of studies have indicated that most cases of peptic ulcers , and gastritis , in humans are caused by Helicobacter pylori infection, and an association has been seen with the development of stomach cancer . A stomach rumble is actually noise from

10600-425: The stomach, while their further and more vigorous effect occurs by stimulation of the medullary center. Salt water and mustard water, which act directly on the stomach, have been used since ancient times as emetics. Care must be taken with salt, as excessive intake can potentially be harmful . Copper sulfate was also used in the past as an emetic. It is now considered too toxic for this use. Hydrogen peroxide

10706-603: The sympathetic nervous system is linked to many health disorders, such as heart failure , gastrointestinal problems, immune dysfunction as well as, metabolic disorders like, hypertension and diabetes , highlighting the importance of the sympathetic nervous system for health. The sympathetic stimulation of metabolic tissues is required for the maintenance of metabolic regulation and feedback loops. The dysregulation of this system leads to an increased risk of neuropathy within metabolic tissues and therefore can worsen or precipitate metabolic disorders . An example of this includes

10812-445: The thoracolumbar division – the thoracic and lumbar regions of the spinal cord – the sympathetic nervous system is said to have a thoracolumbar outflow . Axons of these nerves leave the spinal cord through the anterior root . They pass near the spinal (sensory) ganglion, where they enter the anterior rami of the spinal nerves. However, unlike somatic innervation, they quickly separate out through white rami connectors (so called from

10918-490: The thyroid cells, such as primitive gastroenteric cells, migrated and specialized in uptake of iodide and in storage and elaboration of iodine compounds during vertebrate evolution. In fact, the stomach and thyroid share iodine-concentrating ability and many morphological and functional similarities, such as cell polarity and apical microvilli, similar organ-specific antigens and associated autoimmune diseases, secretion of glycoproteins (thyroglobulin and mucin) and peptide hormones,

11024-417: The transmission of any signal through the sympathetic system: pre-ganglionic and post-ganglionic. The shorter preganglionic neurons originate in the thoracolumbar division of the spinal cord specifically at T1 to L2~L3 , and travel to a ganglion , often one of the paravertebral ganglia , where they synapse with a postganglionic neuron. From there, the long postganglionic neurons extend across most of

11130-458: The use of antiemetics for nausea and vomiting among adults in the emergency department is poor. It is unclear if any medication is better than another or better than no active treatment. Nausea and/or vomiting are the main complaints in 1.6% of visits to family physicians in Australia. Herodotus , writing on the culture of the ancient Persians and highlighting the differences with those of

11236-420: Was first described in the 1960s. This term was coined also to indicate the presence of thyroid autoantibodies or autoimmune thyroid disease in patients with pernicious anemia, a late clinical stage of atrophic gastritis. In 1993, a more complete investigation on the stomach and thyroid was published, reporting that the thyroid is, embryogenetically and phylogenetically, derived from a primitive stomach, and that

#528471