The Digestive System PDF

The Digestive System (Gastrointestinal tract) (alimentary canal) 1-Oral Cavity : Lip, Tongue, Palate and Cheeks. 2-Digestive Tract : Esophagus, Stomach, Intestine and Anal Canal. 3-Digestive Glands (accessory digestive glands):...

The Digestive System (Gastrointestinal tract) (alimentary canal) 1-Oral Cavity : Lip, Tongue, Palate and Cheeks. 2-Digestive Tract : Esophagus, Stomach, Intestine and Anal Canal. 3-Digestive Glands (accessory digestive glands): I II Salivary glands, Liver and Pancreas  The Lips in between a outer and inner lips there are skeletal voluntary muscles called orbicularis oris rem tes Each lip consists of 3 different histological regions: 1-The Outer Surface: It is a thin hairy skin. C.T under the epithelium contains hair follicles, sebaceous and sweat glands. SSK. stratifiedsquamouskeratinized 2-The Inner Surface: It is a mucous membrane. C.T a under the epithelium contains Labial muco-serous glands given saliva. SS nonK. Producewater ntainblooduess.is Iggy 3-The Red Margin: It is called Vermillion and is covered with red wet 2 partially keratinized stratified squamous epithelium. 0 by Licking c tongue. e Me be use for detected some disease:- Pale red may be lead to anemia Blue color a lack of oxygen in the blood lead to increase carbon dioxide lead to cyanosis (cardio respiratory e diseases) Red color means Healthy The Lip Top – SSK (thin Of skin) Red Free Margin Bottom – SS nonK  The tongue The tongue is a mass of lingual striated muscle covered by mucosa, speak __et IrE which mixed of the food during mastication and swallowing and helps to The tongue has 2 surfaces: flake containtaste 1-The Dorsal Surface (rough) the top surface of tongue is covered by partially keratinized stratified squamous epithelium. It contains the lingual papillae off 2-The Ventral Surface (smooth) the undersurface of the tongue is covered by non-keratinized stratifiedseed squamous epithelium  conicalshape Types of Lingual Papillae whitecolor 1-Filiform Papillae: most common They are covered with partially keratinized stratified squamous epithelium with no taste buds. if 2-Fungiform Papillae : They have few taste bubs. Reddish6 in color without keratin, present in edge of the tongue. D hae F.ir consist of several parallel ridges on inanimatsnatres 3- Foliate papillae: each side of the tongue 4- Vallate or Circumvallate Papillar : 8 to 12 in number, present in a V-shaped groove on the dorsal surface of the see_ tongue, rich in taste buds. Von Ebner Glands. They secrete saliva which facilitate taste sensation and washing away food particles. e SIRI__ Filiform Papillae conical in shape Fungiform Papillae Vallate Papillae  onionshape Taste Buds contain 3 layers They are neuro-epithelial organs present on the tongue. e Each taste bud is formed of :- 1-Receptor taste cells or sensory nerve v like microvilli absorption 2-Supporting cells : actasbodyguard 3-Basal Cells : They act as stem cells for renewal of other 2 cells. Tastepore Theplacewherefoodenterstotastebuds Taste Bud  The Esophagus The esophagus is 25 cm long muscular tube. It conduction and connects the : se se food from oral cavity and stomach. No digestion Its wall consists of four layers 0 ee Se_ 1. Mucosa: which is formed of : presentinlipsandtongue a) Non keratinizing stratified squamous epithelium. disease b) Lamina propria of C.T, mucous glands called cardiac glands: alkaline III secretion to neutralization of acid c) Muscularis mucosa smooth muscles omnsdeinmucouse 2.Submucosa: contains mucous glands esophageal glands. secretemucous III 3. Musculosa: Skeletal in upper1/3, mixed in middel1/3, smooth in lower1/3. FIT 4. Adventitia: Connective tissue covering containing B.V. and lymphatic vessels. vessels Its esophaguswithstomach S.S. non keratinized Epi pinnerdirectiony rsouterdirectiony  The Stomach the muscle smooth ’ Sac, muscular, extended. The first station for digestion. ’ Mucosa of the stomach: It lined by simple columnar epithelium and contain branched tubular gastric gland. ’ Cells of gastric fundic glands ffffffstettel ’ bygobletcell produced 1- Simple columnar epithelium: mucous surface secreting and protect the tethered wall of stomach to avoid the HCL (ph 2.5) from stomach which to digest and break ’ i III the food in to small practical's. 2- Chief cells (zymogene cells vesicle) produces pepsin digestion of protein. a - 3- Parietal (oxyntic) cells: secret hydrochloric acid and intrinsic factors. g - 4- Gastric enteroendocrin cells; coordinatethebloodflowandsmoothmusclemovement ’ 5- Stem cells. Regeneration of damage cells e  Fundus 1. The Mucosa : It consists of three 0 parts : ’ a) Epithelial lining. Simple columnar a ’ b) Lamina propria of C.T.: fundic gland narrow gastric pit. ve 09 ’ c) Muscularis mucosa: It is formed of smooth muscles It is responsible for the movements of the mucosa. I d II flow blood ordinate controismootnmuscl.to ’ 2. The Submucosa: Meissners plexus of nerves and lymphatic's and fundic glands. iniiexu ’ 3. Muscularis externa : It is smooth It contains Auerbach's plexus 0 generation of these muscles perform peristaltic contractions. ee e ’ 4. The Serosa: It is the peritoneal or C.T. covering by simple squmous. ’ Function of fundic: Mixing food with gastric juice (HCL+Mucosa g protection +pepsin enzyme+ intrinsic factor absorbed vitamin B12+water and electrolyte. e mstomach andsmallintestine  Pylorus ’ Muscular sphincter ’ Pylorus gland:- Short, wide gastric pit ’ Cells present in pylorus gland: Mucus , stem cell and enteroendocrin  Small Intestine ’ Function absorption of the food mucosainstomach protect stomach wall ’ Length of intestine 6 meter mucosain smallintestine lubricate thefood villiisabsorbtionincreasethespaceinsmallintestine t issharewiththevilliwithsimplething ’ Mucosa forms villi and crypt and simple columnar (absorptive) cells with goblet cells that lubricate the food. Ieee ’ Submucosa contains mucous glands (Brunner`s glands) as in the duodenum; Peyer's patches of lymphatic nodules on one side _e __ as in the ileum. jejunum without gland any ’ The Musculosa: It is smooth muscles usually arranged as an inner erred ad circular and an outer longitudinal layers. It contains Auerbach's free plexus. These muscles perform peristaltic contractions of intestine. ’ The Serosa: _simplesquamous haveperitoneum  iTTTEffgT Small intestine mucosal cells forming brush (striated) border. a d -1-Surface simple columnar absorptive cells on villi with microvilli -2- Goblet cells 3- Paneth (exocrinocytes ) cells secrete anti bacteria lysozymes. fortumor Tumor necrosis factor Present in Base of crypt Ife necrosis make 4-Caveolated cell present in crypt 5- M-cell Ag transporting in crypt 6- Intestinal renewal stem cell in base of crypt. 7-Entero-endocrine Cells. in Crypt  Small Intestine Ileum Duodenum  Large Intestine ’ Function absorbed only water and storage fecal or residual part during defecation ’ No villi only crypt ’ Mucosa :simple columnar (absorptive) cells the water with many goblet cells that to soft the stool. III 0s ’ Enteroendocrin and stem cells ’ The Submucosa meissnersplexus ’ Mascularis external: teniae coli three separate longitudinal ribbons going erost_ see ’ The serosa (fat cell appendices epiploicae) appendix