DIGESTIVE SYSTEM drg ANIS A MAKKY MKes ORAL

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DIGESTIVE SYSTEM drg. ANIS A. MAKKY, MKes ORAL BIOLOGY DEPARTEMENT AIRLANGGA UNIVERSITY SURABAYA, APRIL

DIGESTIVE SYSTEM drg. ANIS A. MAKKY, MKes ORAL BIOLOGY DEPARTEMENT AIRLANGGA UNIVERSITY SURABAYA, APRIL 16, 2007

FUNCTION 1. ingest food 2. break food down physically and chemically into absorbable nutrient

FUNCTION 1. ingest food 2. break food down physically and chemically into absorbable nutrient molecule 3. absorb those molecules into the bloodstream 4. eliminate any indigestible remains.

2 MAJOR GROUPS OF ORGANS IN THE DIGESTIVE SYSTEM ALIMENTARY CANAL : organs thrue

2 MAJOR GROUPS OF ORGANS IN THE DIGESTIVE SYSTEM ALIMENTARY CANAL : organs thrue which food actually passes ACCESSORY ORGANS : they assist in digestion, but no food actually passes through them

ALIMENTARY CANAL * oral cavity * esophagus * pharynx * stomach * small intestine

ALIMENTARY CANAL * oral cavity * esophagus * pharynx * stomach * small intestine * large intestine. ACCESSORY ORGANS * teeth * tongue * salivary glands * pancreas * liver * gallbladder.

THE DIGESTIVE SYSTEM PERFORMS 6 BASIC ACTIVITIES: Ingestion Propulsion Mechanical Digestion Chemical Digestion Absorption

THE DIGESTIVE SYSTEM PERFORMS 6 BASIC ACTIVITIES: Ingestion Propulsion Mechanical Digestion Chemical Digestion Absorption Defecation

ORAL CAVITY STRUCTURES 1. deciduous teeth (20) 2. permanent teeth (32) 3. tongue a.

ORAL CAVITY STRUCTURES 1. deciduous teeth (20) 2. permanent teeth (32) 3. tongue a. skeletal muscles b. moves food mass “bolus” c. appropriate use of “lingual” terminology

ORAL CAVITY STRUCTURES 4. major salivary glands (3 pair) a. parotid - masseter -

ORAL CAVITY STRUCTURES 4. major salivary glands (3 pair) a. parotid - masseter - mumps b. submandibular - medial aspect of the mandibular body - duct : lingual frenulum c. sublingual - anterior submandibular gland & under the tongue - its 10 -12 ducts : floor of the mouth.

ORAL CAVITY STRUCTURES 5. minor salivary glands * lingual glands (on the tongue) *

ORAL CAVITY STRUCTURES 5. minor salivary glands * lingual glands (on the tongue) * buccal & labial glands (in the cheek & lip) * palatine glands (in the palate) * glossopalatine glands (on the glossopalatine fold)

SALIVA contains : enzymatic & nonenzymatic protein calcium phosphorus sodium other salt dissolve gasses

SALIVA contains : enzymatic & nonenzymatic protein calcium phosphorus sodium other salt dissolve gasses : N 2, O 2, CO 2 cells (leukocytes : ginggival sulcus) saliva is 99% water

 p. H : depends on the rate of secretion faster : more alkaline

p. H : depends on the rate of secretion faster : more alkaline (meal) sleep : low resting : 5, 81 (parotid gland) 6, 39 (submandibular gland) average : 6, 7 secretion : follow diurnal rhytms total volume : 600 – 700 ml up to 1500 ml

 secretion parotid gland : 60 -65% submandibular : 20 -30% sublingual : 2

secretion parotid gland : 60 -65% submandibular : 20 -30% sublingual : 2 -5% minor gland : 6 -7% sulcus gingival : 10 -100 µl/h

Function of the saliva 1. digestive 2. antibacterial 3. lubrication 4. taste 5. buffering

Function of the saliva 1. digestive 2. antibacterial 3. lubrication 4. taste 5. buffering action 6. hygienic action 7. blood coagulation & tissue repair 8. inhibition of dental caries 9. water balance

Control of saliva secretion 1. taste 2. smell 3. mechanical stimulation 4. mechanical irritation

Control of saliva secretion 1. taste 2. smell 3. mechanical stimulation 4. mechanical irritation 5. mastication of the food 6. chemical irritation 7. distention or irritation of the oesophagus 8. chemical irritation of the stomach 9. pregnancy

PHARYNX 1. oropharynx 2. esophagus : connects pharynx to stomach 3. peristalsis - rhythmic

PHARYNX 1. oropharynx 2. esophagus : connects pharynx to stomach 3. peristalsis - rhythmic smooth muscle contractions propel material inside

LAYER of DIGESTIVE ORGAN mucosa submucosa muscularis serosa

LAYER of DIGESTIVE ORGAN mucosa submucosa muscularis serosa

MUCOSA functions : protecting against pathogens; absorbing nutrients; and secreting mucus, enzymes, hormones the

MUCOSA functions : protecting against pathogens; absorbing nutrients; and secreting mucus, enzymes, hormones the mucosa consists of 3 sublayers: * epithelium : hormone, enzyme, goblet cell * lamina propria : blood vessels, lymph vessels, and lymph nodules * muscularis mucosae : local movements of the mucosa

 submucosa : * contains : ** blood vessels, lymphatic vessels ** lymphatic nodules

submucosa : * contains : ** blood vessels, lymphatic vessels ** lymphatic nodules ** nerve fibers : submucosal plexus = Meissner plexus

 muscularis externa : * 2 layers of smooth muscle : circular & longitudinal

muscularis externa : * 2 layers of smooth muscle : circular & longitudinal * between 2 layers : myenteric plexus = Auerbach plexus * functions : segmentation & peristalsis * in several places : the circular layer thickens to form sphincters

 Serosa : most exterior layer

Serosa : most exterior layer

MUSCLE of GIT : most smooth m. 2 types : 1. multi unit smooth

MUSCLE of GIT : most smooth m. 2 types : 1. multi unit smooth m. 2. visceral smooth m. Smooth m. consist of : actin dense bodies : actin + actin myosin

SMOOTH MUSCLE POTENTIAL 1. Slow waves : rhytmic, not action potential, resting 2. freq.

SMOOTH MUSCLE POTENTIAL 1. Slow waves : rhytmic, not action potential, resting 2. freq. 3 -12 per minutes 3. gaster 3/min. 4. duodenum 12/min. 5. ileum 8 -9/min. 6. cause ? 7. “ sodium-potasium pump”

SMOOTH MUSCLE POTENTIAL 2. Spike potential : true action potential occurs automatically firing level

SMOOTH MUSCLE POTENTIAL 2. Spike potential : true action potential occurs automatically firing level : -40 mvolt RMP : 50 -60 mvolt stimulation : stretch, asetilkolin, parasympathetic

SMOOTH MUSCLE CONTRACTION

SMOOTH MUSCLE CONTRACTION

ESOPHAGUS regulated by : cardiac or gastroesophageal sphincter collapsed when : empty upper 1/3

ESOPHAGUS regulated by : cardiac or gastroesophageal sphincter collapsed when : empty upper 1/3 is skeletal middle 1/3 a mixture lower 1/3 smooth

STOMACH its functions include : * storage of food * chemical and mechanical digestion

STOMACH its functions include : * storage of food * chemical and mechanical digestion bolus chyme (paste) it is found nearly hidden by the liver when it is empty : its J-shaped and collapsed : folds known as rugae

 general anatomic regions a. cardia b. fundus c. body d. pyloric region it

general anatomic regions a. cardia b. fundus c. body d. pyloric region it is important in the process of physical digest gastric pits pyloric sphincter regulates entry into the duodenum

 gastric pits 4 major secretory cells: a. chief cells b. parietal cells c.

gastric pits 4 major secretory cells: a. chief cells b. parietal cells c. G-cell d. mucus cell

a. chief cells : pepsinogen * activation : by low p. H to form

a. chief cells : pepsinogen * activation : by low p. H to form pepsin * pepsin is a protease for protein digestion b. b. parietal cells i. HCl * secretion enhanced by histamine via H 2 recep. * tagamet blocks H 2 histamine receptors to c. inhibit HCl secretion ii. intrinsic factor binds to and allows B 12 absorption in intestines

c. G-cell : gastrin hormone * activates gastric juice secretion & gastric smooth muscle

c. G-cell : gastrin hormone * activates gastric juice secretion & gastric smooth muscle “churning” * activates gastroileal reflex which moves chyme from ileum to colon d. mucus cell : protective role of mucus against acids and digestive enzymes

What prevents the proteolytic enzymes and HCl secreted by the stomach from damaging itself?

What prevents the proteolytic enzymes and HCl secreted by the stomach from damaging itself? There are 3 basic reasons : a thick coat of alkaline mucus coats the stomach walls mucosal epithelial cells are joined by tight junctions and are impermeable to HCl damaged epithelial cells are quickly shed and replaced