diagestion.pptx. .

diagestion.pptx. .

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  3 DIGESTION • CONTENTS •GENERAL ARRANGEMENT • SALIVARY DIGESTION • GASTRIC DIGESTION • PANCREATIC DIGESTION • INTESTINAL DIGESTION • LIVER AND BILE ,ABSORPTION ,MOTILITY,DEGLUTITION,,VOMITING,DEFECATION, • FUNCTION OF LARGE INTESTINE. • NEUROHUMORAL REGULATION OF ALIMENTARY FUCTIONS ,SUMMERY.
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  GENERAL ARRANGEMENT • Thedigestive system begins at mouth cavityand ends in anus .the digestive system includes various parts and accessory organs. • Parts of G.I.T-oral cavity,pharynx,esophagus,stomach,small intestine,large intestine,anal canal • Acessory organs –tongue,teeth,salivary gland,exocrine pancreas,liver,gall bladder the human digestive canal is more than 10 meter[30 feet]long muscular tube,consisting of following parts from above downward-mouth,tongue,pharynx,esophagus,stomach,small intestine,large intestine,rectum and anal canal.the ducts of the salivary gland open into the mouth.
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  SALIVARY DIGESTION • Thereare 3 pairs of salivary glands 1] parotid gland 2]submaxillary or submandibular gland 3]sublingual gland • Parotid gland-these are largest salvary gland situated at the side of face just below and in front of the ear.the secretion of these glands are emptied into the oral cavity by stensens duct. • Submaxillary gland-these gands are situated In submaxillary triangle medial to mandible Saliva from these glands is open into the oral Cavity by whartons duct • Sublingual gland-these are smallest gland situated in mucosa at the floor of mouth. Saliva from these Glands is poured into 5ml-15ml small ducts of ranivus.these Ducts open on small papillae beneath the tongue. The daily secretion From these glands is 1to 1.5 liter/day the ph of saliva is between 6-7 This Photo by Unknown Author is licensed under CC BY
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  FUNCTION OF SALIVARYGLAND 1]Digestion of food- with the help of enzyme amylase and mucin 2]diluting and cooling effect- saliva dilutes the acidic solution 3]buffering action-bicarbonate,phosphate and protein mucin are 3 buffering systems of saliva it keep the ph in optimum range 4]moistening,cleansing ,and antibacterial fuction 5]solvent and role in taste sensation 6]lubrication for mastication,swallowing and speech 7]thirst mechanism-play a part in maintenance of water balance of the body 8]excretory function for harmful substances 9]adjustment of pressure in ear-small amount of secretions are swallowed at repeated interval.during each swallow the pharyngeal opening of eustachian tube is opened and pressure on either side of tympanic membrane are equalized
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  REGULATION AND SECRETIONOF SALIVA • Secretion of saliva is controlled /regulated by autonomic nervous systems. • Parasympathetic nervous system stimulation produces A]abundant secretion of watery saliva B]increase blood flow to salivary gland • Sympathetic nervous system stimulation causes A]decrease in salivary secretion B]decrease blood flow to salivary gland Smell/taste/chewing-----higher centers in brain------salivary nuclei----- sympathetic /parasympathetic-------salivary gland.
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  GASTRIC DIGESTION • Thestomach contains three main type of gland gastric gland,pyloric glandand cardiac gland.gastric gland contains peptic,parietal,and mucus neck cells pyloric gland secrete mucin and gastrin.mucus gland secrete pepsinogen FUNCTIONS 1.DIGESTIVE FUNCTION 2.RESERVOIR FUCTION-act temporarily as a reservoir of ingested food 3.MIXING FUNCTION-stomach mix the bolus and gastric juice by its peristaltic movement. PROTECTIVE FUNCTION-the hcl present in gastric juice destroy many types of bacteria,viruses and micro-organism entering the body
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  REGULATION OF GASTRICDIGESTION • Gastric secretion is regulated by two mechanism 1]Humoral 2]Neural Neural control of gastric secretion is mediated by vagus and sympathetic nerves.stimulation of vagus help in increase secretion of parietal,pepticand mucous secreting cells thus stimulation of vagus is followed by secretion of acid ,pepsin,mucus Humoral mechanism it is principally due to the release of a hormone which on absorption may either stimulate or inhibit the activity of the gastric gland Three phases-cephalic,gastric and intestinal phase about 2/3 of gastric secretion occur during this phase.
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  PANCREATIC DIGESTION ANDREGULATION • During pancreatic digestion,pancreas makes pancratic juices called enzymes.these enzymes break down sugars,fat and starches FUCTIONS 1]pancreas help digestive system by making hormones.these are the chemical messengers that travel through the blood.pancreas secrete insulin it secrete in blood stream and control sugar level 2]convertion of food into fuel for bodys cells 3]exocrine function help in digestion 4]endocrine function help in blood sugar level Regulation of pancreatic digestion Nervous and humoral mechanism is very important pancrease controlled by both autonomic nervous system and endocrine system sympathetic and parasympathetic division help in digestion sympathetic stimulate the glucagon and then glucose is released. Parasympathetic stimulated during restful condition and stimulate insulin and pancreatic juices Humoral system produces 2 hormones 1]secretin produces secrete pancreatic juice and balance ph-7 Cck [cholecystokinin] also secrete pancreatic juice
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  INTESTINAL DIGESTION • Thesmall intestine where most chemical digestion takes place.most of thedigestive enzyme in the small intestines are secreted by the pancreas and enter the small intestines via pancratic duct.the three major classes of nutrients that undergo digestion are protein,lipid and carbohydrates. FUNCTION Main function of small intestine to absorption of nutrients and minerals from food 90%digestion takes place in small intestine Large intestine function absorbing water and electrolyte,producing and absorbing vitamins,and forming and propelling faces towards the rectum for elimination REGULATION Hormones controls different digestive enzymes that are secreted in the stomach and the intestine and absorption for ex the hormones gastrin stimulate acid secretion in response to food intake the hormone stomatostatin stops the release of stomach acid
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  LIVER AND BILE •Liver structure-liver is made up of cells called hepatocytes and a system of blood vessels. Liver consist of many lobes each lobe consist of large number of lobules each lobule is honey comb like structure.the cells are arranged in different plates each plate is one cell thick with a central vein.in between cells ,are bile canaliculi each lobule is surrounded by portal traid the portal traid consist of a branch of hepatic artery ,a branch of portal vein and a tributary of bile duct. • Function-bile production and excretion • Excretion of bilirubin and cholesterol Hormoes and drugs Metabolism of fat ,protein and carbohydrates • Enzyme activation • Storage of glycogen,vitamins and minerals • Synthesis of plasma proteins such as albumin,and clotting Factors. Blood detoxification and purification
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  BILE • Bile isstored in the gall bladder.when bile stored in gall bladder,large amount of water and electrolyte are absorbed.the bile present in gall bladder has increase concentration of bile salts ,bile pigments,cholesterol,fatty acids and lecithin • Fuctions of bile • Most of the fuctions of bile are due to bile salts.bile salts are most important for their role in digestion and absorption ,particularly fats.the bile salts decrease the surface tension of the particles to break the fat globules into minute sizes .this is called the emulsifying or detergent fuction of bile salts.bile salts forms minute complexes micelles with the fatty acids and monoglycerides which help in absorption of fatty acids. • Bile salt helps in activating pancreatic lipase enzymes. • Bile salt in the duodenum stimulate secretion of pancreatic juice rich in enzymes particularly pancreatic lipase. • The alkali nature of bile helps to nutralise the acide chyme in the duodenum. • Bile act as an important vehicle for the excretion of neumorous drugs ,toxins,heavy metals like copper,zinc,and mercury.bile pigments ,enzymes,like alkali phosphatase and pathogenic bacteria like typhoid bacilli are excreted in bile . • Bile excrets a mild laxative effects on the gut by stimulating peristalsis in the small bowel. • Bile has an antiseptic action and inhibits the growth of certain bacteria within the gut.
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  Motility of alimentarycanal- mastication ,deglutition,vomiting,defecation • MASTICATION-it is the first movement of digestive tract.mastication is a voluntary action and accomplish several important functions like solid food particles are broken up and reduced to a size convenient for swallowing • Chewing results in reflex salivation and also serves to mix the saliva with ingested food as to moistened and lubricate it and facilitates act of swallowing. • Chewing of food is important for digestion of all food and specially important for fruits and raw vegetables because these have undigested cellulose membrane around their nutrient portion which must be broken before food can be utilized
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  DEGLUTITION • Deglutition isthe passage of masticated bolus of food from the oral cavity into the stomach. In general swallowing can be divided into 3 stages. 1]oral or buccal stage-this stage consist of passage of the bolus from the oral cavity into the oro-pharynx hear bolus voluntarily rolled and squeezed and go into pharynx. 2]pharyngeal stage-the pharyngeal stage is concerned with passage of bolus through the pharynx into the oesophagus and preventing its entry into respiratory tract .soft palate pulled upward and preventing reflux of food into nasal cavity. 3]oesophageal stage-when the bolus enters the esophagus and passes down to enter the stomach is called the esophageal stages peristaltic movement propels the food into stomach.
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  VOMITING • VOMITING –isthe forceful expulsion of content of the stomach and often,the proximal small intestine,it is due to various causes acid-base derangement, volume and electrolyte depletion,malnutrition and aspiration pneumonia. • Act of vomiting 3 event 1]nausea- is associated with decresed gastric motility. 2]retching-refers to spasmodic respiratory movements conducted with a closed glottis 3]emesis or vomiting-is when gastric and often small intestine content are propelled upto and out of the mouth. DEFECATION Also called bowel movement the act of eliminating solid or semi solid waste material from the digestive tract .macular contraction in the walls of the colon move fecal material through the digestive tract to the rectum.
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  HEAR WE FINISHEDOUR DIGESTION CHAPTER THANK YOU