GIT Physiology PDF

GIT PHYSIOLOGY: DIGESTIVE SYSTEM Function: 1. Digestion 2. Absorption 3. Defecation - Divided into 2 parts: A. Alimentary canal/GIT (GASTROINTESTINAL TRACT) - hollow muscular tubes. (Murag turbo) B. Accessory digestive organs - assist the alimentary canal in terms of digesti...

GIT PHYSIOLOGY: DIGESTIVE SYSTEM Function: 1. Digestion 2. Absorption 3. Defecation - Divided into 2 parts: A. Alimentary canal/GIT (GASTROINTESTINAL TRACT) - hollow muscular tubes. (Murag turbo) B. Accessory digestive organs - assist the alimentary canal in terms of digesting the food. I. Accessory digestive organs/ADO 1. Salivary Gland - secretes saliva into the mouth (buccal cavity) Saliva composition: - 99.5% water H2O - 0.5% solutes - Immunoglobulin A (antibody) - to protect the mouth from bacteria - N production: 1000 - 1500 mL 2 types of protein: A. Serous secretion - starch digesting “enzyme” (responsible for breaking down) the “STARCH DIGESTING ENZYME”a.k.a Salivary amylase/ptyalin EX: rice B. Mucus secretion - secretes “mucin” - moisture to the food + binding the food together (bolus). - 3 glands: a. Parotid gland (reference is ear) - largest salivary glands; loc: ant. Inferior to the ears; in-between the skin and the masseter. b. Submandibular Gland - loc: beneath the base of the tongue in the posterior part of the floor of the mouth. c. Sublingual Gland - loc: superior to the submandibular gland. - Controlled by the ANS (autonomic nervous system) Sympathetic = decrease production saliva Parasympathetic = increase production of saliva 2. Tongue - Floor of the mouth A. Extrinsic muscle of the tongue - movements of the tongue side to side, in & out. B. Intrinsic muscle of the tongue - altering the shape of the tongue (during speech) C. Taste buds - receptor for the taste; stimulate the salivary glands 3. Teeth “Dentes” - 2 sets of teeth A. Deciduous teeth - a.k.a Milk teeth, Temporary teeth, Baby teeth. - 20 in number o 4 incisors o 2 canines o 4 molars - 1st teeth to erupt: lower central incisors; during 6 mos. - All deciduous teeth are lost at the age of 6-12 y.o. B. Permanent teeth - 32 in number o 4 incisors o 2 canines o 4 premolars Made by: Jerramy Nunez (do not distribute) o 6 molars 4. Pancreas - Both exocrine &endocrine glands. - Exocrine: produce enzymes - Endocrine: produces hormones - Consists of head, neck, body, & tail (murag worm) - Location: greater curvature of the stomach - (+) Pancreatic juice - N: 1,200 - 1,500 mL 3 enzymes: Carbohydrate digesting enzyme / “pancreatic amylase” Trypsinogen - protein digesting enzyme (ex: fish, meat, chicken, pigeon) [no = means inactive in form]. o Trypsin - active form; it is important to digest protein o Passed trough a brush “border villi” - “Enterokinase” converts trypsinogen into trypsin. o Triglyceride digesting enzyme/pancreatic lipase (ex: fats, they are in the form of oil [canola oil, vegetable oil]). *Trypsinogen remains inactive in pancreas. *If it turns to trypsin in pancreas = pancreas will inflamed / pancreatitis. - Relaxation of the sphincter of oddi: according to guyton: it is always close; needs to open and relax to eject the pancreatic juice. It has 3 condition: 1. Release of the cholecystokinin 2. Peristaltic wave in the common bile duct (vibrates) 3. Intestinal wave 5. Liver - Heaviest gland - 2nd largest organ - Functional unit: lobule - there is a cell inside which is the hepatocytes (which is responsible for the production of “BILE”. o Bile is for the Emulsification of fats ▪ Composition of Bile: H20 Cholesterol Bile salts Bile pigment (responsible for the color of the bile) - yellow-olive green: N production of bile = 800 - 1000 mL 6. Gallbladder - Storage of bile Made by: Jerramy Nunez (do not distribute) - Inferior to the liver II. Alimentary Canal/GIT (Gastrointestinal canal) 1. Mouth - Buccal/oral cavity - Lateral wall of the mouth: cheeks - Roof: ant. Portion = ‘hard palate's post. Portion = “soft palate” - Floor: tongue 2. Pharynx/Throat - 3 parts: A. Nasopharynx - only for respiration B. Oropharynx C. Laryngopharynx Oro and laryngo both for respiration and digestion - This is the movement from the mouth to the stomach - swallowing/DEGLUTITION A. Voluntary stage - passageway of bolus into oropharynx. B. Involuntary stage/Pharyngeal stage - bolus in oropharynx; - Inside the oropharynx there is a receptor - Fastest stage BOLUS: receptors in Oro activates DEGLUTITION center: LOWER PONS & MEDULLA OBLONGATA If activated: 1. Soft palate + uvula = moves superiorly to close the nasopharynx 2. Larynx (voice box) = forward + upward 3. Epiglottis (one of the 6 cartilages of the larynx) = backward + downward - The breathing is interrupted for 2-3 seconds Ratio: it widens the opening of the esophagus Made by: Jerramy Nunez (do not distribute)  C. Esophageal stage = the bolus is in the esophagus. 3. Esophagus - 25 cm long - Composed of smooth muscle: Peristalsis - (-) Digestive enzyme; (-) absorption - Passageway of bolus - Has 2 sphincters: a. Upper esophageal sphincter b. Lower esophageal sphincter/cardioesophageal sphincter = inability of the LES to close: GERD (Gastroesophageal Reflux Disease) (+) heartburn / burning sensation; relieve by antacid 4. Stomach - C/J shape - For storage of food = 4 Liters - Parts: a. Cardia = opening portion b. Fundus = broad portion c. Body = central portion of the stomach d. Pylorus = terminal portion i. Pyloric Sphincter e. Greater and lesser curvature - 2 tubular glands: a. Gastric glands - gastric juice (N = 2000 - 3000 mL) i. Mucus neck cells: mucus ii. Chief cells: responsible for the production of pepsinogen (inactive) - pepsin (active) [ a protein digesting enzyme] iii. Parietal cells: production of the intrinsic factor + HCL (most powerful acid in the body) [activates pepsinogen into pepsin] 1. Reabsorption of the B12 (intrinsic factor) [reabsorbed in ileum] 2. Pernicious anemia = poor reabsorption of vitamin B12 b. Pyloric gland i. G - cell: produces hormones “GASTRIN” 1. GASTRIN is for the growth, the maturation, and development of gastric glands. 2. Increase Gastrin = increase gastric juice [ex of food that has gastrin: coffee, chocolate] Made by: Jerramy Nunez (do not distribute)  a. INHIBITION OF GASTRIN = somatostatin 5. Small intestine - Longest alimentary canal - Major digestive organ; water 90% reabsorption - Major events of absorption - Parts: a. Duodenum b. Jejunum c. Ileum - (+) Enterogastric reflex = tightening of the pyloric sphincter - Hormones: a. Secretin =- stimulates the liver (bile) and pancreas (PJ) b. cholecystokinin = gallbladder (bile) contraction - Chyme = white cream/heavy cream; release 2-3 teaspoons. - Journey of the chyme in the looping coils of small intestine: - 3 - 6 hours = well-balanced diet - 6 hours = fats 6. Large Intestine - Largest alimentary canal - Parts: a. Cecum = sumpay sa small intestine (ileum) b. Colon i. Ascending ii. Transverse iii. Descending iv. Sigmoid c. Rectum i. (+) Stretch: defecation reflex ii. Mu atras ug balik sa rectum if naay stimulus sa gawas d. Anal canal e. Anus - (+) Ileocecal sphincter - Function: haustral contraction = stretching of the large intestine - Good bacteria: fermentation of the stool; creates a gas called METHANE GAS (utot) - N = 500 mL - Undigested food (stool) in the large intestine: 72 hours (3 days) - STERCOBILIN = Responsible for the color of the stool (golden brown) - Bilin = break down of bilirubin Made by: Jerramy Nunez (do not distribute)  - Distention of the colon = napuno ug stool: Megacolon/Hirschsprung disease Neural Control of the GIT - Enteric Nervous System 1. Myenteric / Auerbach plexus = movements for GIT; perstasis / contractions 2. Submucosa / Meissner’s plexus = secretions (mucus) & blood flow for GIT - Carbohydrates 1. Monosaccharide (mono = 1; saccharide = sugar) - Simple sugar - the only sugar that can pass through a cell wall since they are small. - Ex: glucose, galactose, fructose, ribose 2. Disaccharide (di = 2; saccharide = sugar) - Double sugar - Ex: - Sucrose: glucose + fructose = table sugar - Maltose: glucose + glucose = beer sugar - Lactose: glucose + galactose = milk sugar - SML = SAN MIG LIGHT 3. Polysaccharide - Many sugar - Ex: starch; Glycogen - Starch - Root vegetables - Grain products - Glycogen - Animal tissue (liver) Digestion In the mouth STARCH Breaksdown MALTOSE In the Stomach PROTEIN Breaksdown LARGE POLYPEPTIDES Made by: Jerramy Nunez (do not distribute) In the Small intestine TRYPSIN LARGE POLYPEPTIDES breaksdown PEPTIDE PANCREATIC TRIGLYCERIDES breaksdown MONOGLYCERIDE LIPASE + BILE PANCREATIC AMYLASE + BRUSH BORDER VILLI SUCRASE SUCROSE breaksdown GLUCOSE, FRUCTOSE LACTASE LACTOSE breaksdown GLUCOSE, GALACTOSE MALTASE MALTOSE breaksdown GLUCOSE, GLUCOSE Quadrants in the ABDOMEN Right Upper Quadrant Left Upper Quadrant ® Kidney (L) Kidney Liver Stomach Gall bladder Spleen (during abdominal trauma, Pancreas (head & neck) the 1st organ to rupture) Pancreas (body & tail) Right Lower Quadrant Left Lower Quadrant Cecum Sigmoid colon Appendix (appendicitis; this is 2 to (L) ovary obstruction on the neck of the appendix;ex: seeds) ® ovary CAR Made by: Jerramy Nunez (do not distribute) 9 REGIONS IN THE ABDOMEN RIGHT EPIGASTRIC REGION LEFT HYPOCHONDRIUM Stomach HYPOCHONDRIUM Liver Spleen Gallbladder Pancreas FLANK AREA UMBILICAL REGION FLANK AREA Smal Intestines INGUINAL REGION SUPRAPUBIC REGION INGUINAL REGION Large Intestine ORGANS 1. Stomach - Location of pain: Epigastric region - Referred pain: Right shoulder / Lateral border of the right scapula 2. Small Intestine - Location of pain: Umbilical region - Referred pain: Low back area 3. Large Intestine/Colon - Location of Pain: Suprapubic region - Referred pain: Sacrum 4. Liver & Gallbladder - Location of Pain: Right upper quadrant; Right Hypochondrium - Referred pain: Right shoulder, Shoulder blades 5. Spleen - Location of Pain: Left Upper quadrant; Left Hypochondrium - Referred pain: Left shoulder 6. Pancreas - Location of pain: L UQ; L Hypochondrium - Referred pain; Left Shoulder Made by: Jerramy Nunez (do not distribute) Made by: Jerramy Nunez (do not distribute)