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CHAPTER 14 DIGESTIVE SYSTEM VOCABULARY WORDS alimentary canal lesser omentum appendix lingual frenulum bile liver cecum lumen chyme masticated duodenum pancreas esophagus phenylketonuria (PKU) gallbladder pyloric sphincter/valve greater omentum rugae ileocecal valve small intestine ileum stomach jejunum uvula Large intestine COLOR CODE – Plate 78 Oral cavity – peach liver - red Pharynx – dark green gall bladder – light green Esophagus – brown pancreas - purple Stomach – magenta (dk. pink) spleen - tan Duodenum – light blue submandibular - yellow Jejunum – blue sublingual - orange Ileum – dark blue parotid – light green Large intestine – orange Appendix – pink Rectum – gray Tongue – red Color Code – Plate 79 Frenulum – aqua Gingiva (gum) – pink Hard palate – dark blue Soft palate – light blue Uvula – purple Oral pharynx – tan Palatine tonsil – green Tongue – red Sublingual gland – orange Submandibular gland – yellow Parotid gland – light green Epiglottis – brown Lingual tonsils – dark green Color Code – Plate 83 Fundus – dark blue submucosa - pink Body – blue oblique muscle - brown Pylorus – light blue circular muscle – light brow Pyloric sphincter – purple longitudinal muscle - tan < curvature – aqua serosa - magenta > Curvature – turquoise diaphragm - gray Rugae – peach esophagus - yellow Surface/mucous cells – dark green duodenum - red Parietal cells – green Chief cells – light green Muscular mucose - orange Color Code – Plate 87 Liver – red Gallbladder – light green Pancreas – gray Spleen – tan Abdominal aorta – pink Inferior vena cava - magenta I. Anatomy of Digestive Sys. A. 2 main groups of organs 1. those forming the alimentary canal 2. accessory digestive organs B. Alimentary canal 1. performs all dig. Functions 2. functions: ingesting, digesting, absorbing, defecation C. Accessory digestive organs assist in the process of digestion II. ALIMENTARY CANAL A. Also called the GI tract (gastrointestinal) B. Approx. 9m / 30 ft. long C. Shorter in a living person muscle tone D. Mouth / Oral Cavity 1. masticated chewed 2. break down of food b/g b/f food leaves mouth 3. tongue – continually mixes food w/ saliva & initiates swallowing 4. lingual frenulum a. fold of mucous membrane that secures tongue to floor of mouth b. limits posterior mmt. of tongue c. if extremely short “tongue-tied” E. Pharynx 1. common passageway for food, fluid, air 2. has 3 sub÷ a. nasopharynx – part of respiratory passageway b. oropharynx – posterior to oral cavity c. laryngopharynx – continuous w/ esophagus 3. peristalsis a. propelling mech. for food from pharynx i/t esophagus b. alternating contraction of 2 muscle layers Picture A shows peristalsis F. Esophagus 1. passageway for food to stomach 2. food conducted by peristalsis 3. has 4 basic tissue layers tunics a. mucosa *inner most layer *lines cavity / lumen of esophagus *epithelium is >ly simple columnar b. submucosa *just b/n mucosa c. muscularis externa *has 2 layers of smooth muscle: inner circular layer outer longitudnal layer d. serosa G. Stomach 1. C-shaped; left side of abdominal cavity 2. when full approx. 4-L / 1-gal of food 3. covered by omentum a. > omentum * xtension of peritoneum * drapes downward & covers abdominal organs like a lacy apron b. < omentum * double layer of peritoneum * covers from liver to <er curve 4. has 3 muscle layers a. longitudinal b. circular c. muscularis externa - obliquely arranged layer 5. where chemical break down of proteins b/g 6. produces 2-3 L of gastric juice / day a. intrinsic factor – sub. needed for Vitamin B-12 absorption b. chief cells – produce protein-digesting enzymes c. parietal cells – produce HCl (corrosive, activates pepsinogen pepsin) 7. chyme a. sub. from food processed b. resembles heavy cream c. enters small intestine thru pyloric sphincter (3-6 hr. journey thru sm. int.) H. Small Intestine 1. mj. dig. organ 2. where chemical dig. really begins 3. where nearly all food absorption occurs 4. longest part of alimentary canal – length: 2½ – 7m / 8 – 18 ft. 5. has 3 subdivisions: a. duodenum b. jejunum c. ileum 6. extends from pyloric sphincter to ileocecal valve a. pyloric sphincter *controls food mmt. i/t sm. int. *prevents sm. int. from being overwhelmed (“gatekeeper”) b. ileocecal valve I. Large Intestine 1. larger in diameter, shorter in length than sm. int. 2. passage of feces (undigested food particles) to end of dig. tract 3. has 5 sub÷ a. cecum b. appendix – hangs from cecum & collects bacteria c. colon d. rectum e. anal canal III. Accessory Digestive Organs A. Salivary Glands 1. 3 pr. that empty secretions i/t mouth a. parotid glands *larger *inflammation mumps b. submandibular glands just inferior to midmandible c. sublingual glands deep & inferior to floor of mouth 2. saliva *prod. of salivary glands *mixture of mucous & serous fluid *contains enzyme amylase wh/ b/g process of starch digestion B. teeth 1. for mastication 2. have 2 sets: *deciduous/baby teeth (20 teeth) *permanent teeth (32 teeth) C. Pancreas 1. extends across abdomen from spleen to duodenum 2. produces enzymes to break down all categories of digestible foods 3. enzymes are secreted i/t duodenum 4. enzymes neutralize acidic chyme from stomach 5. pancreatic juice contains enzymes: a. amylase – starch dig. b. trypsin – protein dig. c. lipase – lipid dig. d. nuclease – nucleic acid dig. D. Liver 1. largest gland in body 2. has 4 lobes wh/ a/m completely cover stomach 3. digestive function produce bile 4. other functions: a. ATP production b. degrades hormones c. detoxify drugs/alcohol d. make cholesterol (has > 500 functions in body) 5. Bile a. yellow-green, H2O-y solution b. contains: bile salts, bile pigments, cholesterol, phospholipids, electrolytes c. emulsifies fats (breaks lg. globules i/t sm.r ones E. Gallbladder 1. sm. green sac snuggled i/t a fossa of inferior surface of liver 2. stores bile when digestion is not occurring 3. gallstones a. occurs when bile is stored for too long in the gallbladder or when too much H2O is removed from bile b. cholesterol crystallizes forming sharp stones gallstones IV. Digestive Diseases/conditions A. Jaundice 1. occurs when blockage prevents bile from entering sm. int./ actual liver prob.s 2. bile accumulates & backs up i/t the liver & b/g to enter bloodstream 3. pigments circulate t/o the body tissues to b/c yellow jaundiced B. Hepatitis 1. inflammation of the liver 2. > often due to viral inf. contaminated H2O or needles C. Cirrhosis 1. chronic inflammatory cond. of liver 2. liver is severely damaged & b/c hard & fibrous 3. al/m guaranteed when drinking alcohol for many years 4. a/s a consequence of hepatitis D. Phenylketonuria (PKU) 1. inability to digest/use protein (specifically the amino acid phenylalanine) 2. special diet is needed brain damage & MR occurs