By V. Makas. Murray State University.
This is the maximum quantity of acid that can be secreted Classification by the stomach buy dilantin 100 mg low price. The following parameters are looked for in tric juice is collected by Ryle’s tube dilantin 100 mg on line. Usual tests performed the gastric content sample: Volume of acid (acid output) purchase 100mg dilantin with mastercard, are given below cheap 100mg dilantin fast delivery. Examination of gastric contents can be divided into Special Test to Detect Acid Output three types according to the time of examination: Histamine Test 1. At rest: Gastric juice is collected after the patient Historically, histamine was the first standard stimulant awakes in the morning, but still lying on the bed. After a meal in the post absorptive phase: A specific weight of histamine phosphate is injected subcutaneously diet is provided, which has a fixed composition (also with simultaneous administration of antihistaminic agent known as fractional test meal analysis) followed by to prevent the untoward side effects. After a specific stimulus: A specific stimulus for induc gastric content is aspirated and analyzed. It is helpful in tion of acid secretion is applied following which the gas the diagnosis of pernicious anemia, subacute combined tric content is withdrawn. Mainly the maximum amount degeneration of spinal cord and assessing the maximum of acid output is checked in these type of tests. Test for Pepsin Pentagastrin (Peptavlon) Test Pepsin inhibitors are used for analysis of pepsin derived Pentagastrin is injected subcutaneously at a dose of 6 µg/ from pepsinogen for research purposes. Test for Mucous Insulin Test (Hollander test) This test is based on the fact that in a state of hypoglyce Protein content of gastric mucous is measured, normal mia, produced by insulin, in turn causes vagal stimulation. The level is increased in chronic The direct vagal action on parietal cells, leads to acid secre hypertrophic gastritis (Menetrier disease). Therefore, insulin can be used for measuring acid Test for Intrinsic factor output. No increase in acid vitamin B12 is impaired as occurs in chronic atrophic gastri production should occur if the vagal resection is complete. Schilling test is used for evaluation of patients with suspected pernicious anemia but can also Fractional Test Meal Analysis be used as diagnostic test for pancvreatic efficiency result ing in impaired absorption of vitamin B12 since gastric R Patient is allowed to take a meal that has a particular com binder protein is not cleared from intrinsic factor due to position, following which small fractions (10 ml) of gastric reduced pancreatic proteolytic activity. This test indicates the acid secretion capacity in Gastrin is secreted by G cells present in the antropyloric the post-absorptive phase. However, it may not be always accurate: Normal fasting level of gastrin is 20150 pg/mL. Diagnex blue which contains a cation exchange resin els are higher in: with an indicator Azure A is given orally to the patient. Gastrin provocative tests: These tests are used to dif its color is compared with standards to check for the ferentiate between hypergastrinaemia and gastric acid concentration of gastric acid. It is contraindicated in renal disorders, malabsorption, by more than 50% of basal value in 515 minutes, it is etc. Calcium infusion test A variety of etiologic agents have been implicated in the cause of acute gastritis. Diet and personal habits: the details of the contour of the lower esophagus, stomach 2. Severe stress A fiberoptic gastroscope is introduced into the stomach Chronic gastritis, if untreated leads to peptic ulcer. It gives an opportunity to visualize the lumen of the Peptic ulcer means ulcer in the stomach (gastric ulcer) or stomach, so that the ulcer details can be seen. A biopsy of the ulcer can be taken to study the type of pepsin in the gastric secretion produces damage to the ulcer (to exclude malignancy). The tissue is also cultured to study the organism fore, peptic ulcer is called acid-peptic disease. The gastroscope can be introduced into the duode Pathophysiology num and biliary tract to study further details. Urease test is performed from the biopsy sample for defense, or by hypersecretion of acid or infection. This allows the pH of the epithelial cells to remain radiological abnormalities are absent. It protects great importance due to its relationship with peptic ulcer mucosal epithelium from injury caused by acidic chyme. In chronic stress, ulcer is pro duced (stress ulcer) by chronically elevated level of cate 5. Hypersecretion of Acid Scientists contributed Gastric acid secretion increases in chronic anxiety. Peptic ulcer is common in business executives as most of them lead a life either in hurry or in worry. Therefore, it is generally believed that hurry, worry, and curry are the causes of peptic ulcer. Chronically increased secretion of Barry J Marshall J Robin Warren acid (hyperchlorhydria) produces peptic ulcer by damag (Born 1951) (Born 1937) ing the mucosal barrier. The Nobel Prize in Physiology or Medicine 2005 was awarded jointly Conditions that cause hyperchlorhydria are: to two Australian physicians Barry J. This is a Gram-negative bacillus that secretes an of blood) or malena (dark, tarry stool), vomiting (due to enzyme called urease that converts urea into carbon pyloric obstruction), and peritonitis due to perforation of dioxide and ammonia. It Specific Treatment also inhibits somatostatin secretion from D cells that The specific treatment includes use of following drugs: facilitates gastrin release and consequently increased 1. Note the portion of stomach (as shown within the two dotted lines) removed in gastrectomy Surgery for peptic ulcer. This is the most effective Yoga Therapy and Other Measures medicine for the treatment of peptic ulcer. The usual Yoga therapy like practice of relaxation techniques, ade protonpump blocker used is omeprazole. Therefore, it promotes cold milk and avoidance of spicy food & alcohol also help ulcer healing. Muscarinic blockers: Atropine and pirenzepine are used to block the M and M receptors. However, Sometimes inspite of effective use of medicines, the dis as the noncholinergic vagal innervation dominates ease is not cured. Vagotomy: There are different types of vagotomy such Therefore, muscarinic blockers are not used in peptic as truncal vagotomy (cutting the trunk of vagus nerves ulcer treatment. Gastrin blockers: As gastrin is the most potent stimu vagotomy (cutting the vagus nerve that supplies only lator of acid secretion, effort has been made to dis stomach), and highly selective vagotomy (cutting the cover gastrin antagonists. However, a successful gas vagus nerve that preferentially innervate the parietal trin blocker has not yet been discovered. Usually, the parietal cell vagotomy is a gastrin blocker is used recently for the purpose.
Protection of mucosa: The mucus and alkaline pH of biliary 100 mg dilantin sale, and intestinal secretions discount 100mg dilantin mastercard. It is secreted from a heterogeneous group of sali- food particles in which the first step is to hydrolyze macro vary glands located in and around the mouth cavity generic dilantin 100mg with mastercard. Through reflex mechanisms cheap dilantin 100 mg fast delivery, food in intestine inhibits eponymously for the discovery of the duct of the gastric secretion and motility. Major salivary glands are three pairs: parotid, sublin- gual and submandibular glands. There are many minor salivary glands located in the mucosa of oral cavity, at the pharyngeal outlet, in the palates and in buccal pouches. Based on nature of secretion: Salivary glands may be serous that exclusively release watery secretions, mucous that secrete viscous secretion mainly containing mucus and mixed that secrete moderately viscous secretions. They pour their secretion into the mouth cavity by means of parotid duct (duct of Stensen), which opens into the oral cavity at the level of second molar tooth (Fig. Histology of Salivary Glands Sublingual Glands Salivary gland consists of base units called salivon. Each salivon consists of acinus, intercalated duct and striated These glands are situated below the tongue in the floor of duct (Fig. Secretions from these glands drain directly into the Acinus mouth by means of sublingual ducts (ducts of Rivinus). Sublingual glands Acinus is a sac like structure containing many pyramidal are predominantly mucous glands. Serous cells of acinus contain many endoplasmic retic- Submandibular Glands ulum and zymogen granules, and secrete digestive Submandibular, also called submaxillary glands are situ- enzyme, whereas mucous cells contain mucin droplets ated below the inner ramus of mandible on both sides. Preganglionic fibers for parotid gland are present in 9th cranial nerve that originate in inferior salivary nucleus These ducts are lined by cuboidal cells. Secretion from and terminate in otic ganglion from where postgangli- these duct epithelial cells modifies the ionic composition onic fibers originate and innervate the gland (Fig. Secretion coming out of duct is called present in the 7th cranial nerve that originate from modified or final secretion. In normal situation, parasym- pathetic innervation is the major neural factor for salivary Sympathetic Innervation secretion. Sympathetic fibers originate from upper cervical segments and terminate in superior cervical ganglion. Postganglionic Parasympathetic Innervation fibers leave the ganglion and innervate acini, duct and blood The centers for parasympathetic fibers are located in medulla. Blood flow and metabolism are proportionate nate concentration as time to add more bicarbonate to the rate of saliva formation. However, if the increase in flow is due to parasympathetic 50 mL/min/100 g of salivary tissue. Blood flow to salivary glands is about 10 times the more that increases salivary content of bicarbonate. Salivary Secretion Functions of Saliva Saliva performs many important digestive and non-diges- Rate of Secretion tive functions. Normally, we never realize the amount of saliva vary amylase, which causes splitting of starch. However, an orexigenic stimulus, especially sight, absence of salivary amylase (if pancreas is intact). We realize the importance of salivation when digestion by ptyalin takes place in the stomach, as food the secretion becomes less and mouth becomes dry. IgA in saliva provides local immunity and lactoferrin in saliva Organic Solids is bacteriostatic. Saliva keeps the mouth cavity and tongue moist, which lysozyme, lactoperoxidase, carbonic anhydrase, lingual facilitates speech. Other organic solids include saliva is realized when mouth becomes dry due to kallikrein, blood group substances, secretory immuno- decreased salivary secretion that impairs speech. Taste is perceived by Cations like sodium, calcium, potassium, and magnesium the taste buds present in the tongue. For taste of food ions, and anions like chloride, bicarbonate, phosphate, to be well appreciated, food particles should better sulfate, and bromide ions constitute the inorganic solids. The mucin in saliva The concentration of sodium and chloride ions in saliva lubricates food. Saliva contains bicarbonate which buffers gastric acid of secretion, higher is the tonicity. The tonicity of saliva is to some extent in the stomach, and therefore reduces about 70% of that of plasma. Proline rich protein in saliva protects enamel of the The pH and K Content of Saliva teeth and thus provides them strength. In animals, salivation (panting) is an important process anticipation, thought, sight and smell of food, discussion of dissipation of heat and therefore, has contribution on food, and presence of foodin the mouth cavity. Control of Salivary Secretion Salivary secretion is controlled exclusively by the neu- Mechanism of Secretion ral mechanisms. Both sympathetic and parasympathetic Salivary secretion occurs in two stages: secretion in the stimuli influence salivary secretion. Secretion in Acinus of Gland Neural Control In the gland acini, the secretion is called primary secretion Parasympathetic Stimulation in which amylase concentration is more. Secretion in Ducts The composition of secretion in the ducts when the fluid passes through the intercalated and striated ducts, is modified. The ducts do not change the volume of saliva but only modify the composition of the primary secretion (Fig. The important stimuli are determine ionic compositions of primary and modified secretions. It increases secretion by causing vasodilation (via regulation of saliva is negligible. Applied Physiology Sympathetic Stimulation Xerostomia Stimulation of sympathetic fibers (sympathetic fibers to This is a condition in which there is consistent decreased salivary gland originate from superior cervical ganglion) secretion of saliva. This causes dryness of mouth, and pre- temporarily increases secretion but finally decreases it. The transient increase is due to contraction of myoepi- is a common in acute stressful situation that happens due thelial cells of the glandular tissue. However, sympathetic stimulation causes vasocon- striction that decreases saliva formation and makes Sialorrhea the secretion thick. In this condition, salivary secretion is increased persis- Reflex Secretion tently. This reflex secretion is unconditioned as this Sialolithiasis is present since birth (does not need learning). However, This is the condition in which stone is formed in the ducts salivary secretion due to smell or thought of food is a con of salivary gland. Salivary secretion exclusively occurs in the cephalic Viral infection of parotid gland is seen commonly in phase (sight, smell and thought of food, presence of food children (mumps).
10 of 10 - Review by V. Makas
Votes: 157 votes
Total customer reviews: 157