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Digestive System.

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Presentation on theme: "Digestive System."— Presentation transcript:

1 Digestive System

2 AKA G-I Tract Alimentary Canal

3 Overview Consists of Mouth, pharynx, esophagus, stomach, small intestine, large intestine, anus About 30’ in length Accessory Organs Teeth, tongue, gall bladder, salivary glands, liver and pancreas Glands secrete saliva, bile and enzymes

4 GI System

5 Process Includes Ingestion Mechanical – chewing, churning
Propulsion – swallowing and peristalsis Chemical – breakdown via enzymes Absorption – transport of end products into blood Defecation – elimination as feces

6 GI Process

7 Peritoneum and cavity Parietal peritoneum surrounds cavity, lines body wall Visceral surrounds organ Serous membrane allows organs to glide/expand Retroperitoneal refers to organs in the dorsal region Peritonitis = inflammation of peritoneum Perforation = infection

8 Peritoneum

9 Quadrants

10 Regions

11 Regions

12 Mesentery Double layer of peritoneum, holds organs in place
Omentums - protection Lesser = fatty skin, superficial near the stomach Greater = deeper, made of connective tissue, significant fat Three layers of fascia – Skin, Fascia, mesentary

13 Messentery

14 Messentary

15 Omentum

16 Greater Omentum

17 Histology Smooth muscle - peristalsis Glands with ducts
Nerves, arteries and veins

18 Histology

19 Mouth Point of Origin Oral cavity Tongue Soft and hard palate Uvula
Oropharynx Epiglottis Larynx/pharynx Esophagus

20 Mouth Anatomy

21 Mouth Anatomy

22 Salivary glands Produce saliva, a mixture of water, ions, mucous, and enzymes Dissolve food Wets food to help bind it to become a bolus Neutralizes acids, helps growth of beneficial bacteria Intrinsic –in tongue, palate, lips and cheeks Extrinsic = outside mouth Parotids Submandibular Sublingual

23 Salivary Glands

24 Pharynx Oso Laryngopharynx Lined with epithelial cells for protection

25 Pharynx

26 Esophagus Muscular tube Propels swallowed food to stomach
Passes through diaphragm (esophageal hiatus) into abdomen Join the stomach at cardiac orifice Cardiac sphincter prevents reflux or regurgitation of acid

27 Esophagus

28 Esophagus

29 Esophagus

30 Stomach Food churned into chyme; a paste
Secretes pepsin – a protein digesting enzyme and HCl Waters, electrolytes, some drugs absorbed through stomach Anatomy Cardiac orifice, fundus, lesser and greater curvature, pylorus Rugae = numerous longitudinal folds of mucosa which flatten as stomach fills, allows expand

31 Stomach

32 Stomach

33 Stomach

34 Junction

35 Stomach

36 Small Intestine Longest part of alimentary canal
Most enzymes involved in small intestine come from pancreas Three divisions – each approximately Duodenum – 5% Jejunum – 40% Ileum – almost 50%

37 Duodenum Receives digestive enzymes from pancreas
Bile from gall bladder and liver Almost all nutrients are absorbed in small intestine Large surface area, great length

38 Small Intestine

39 Small Intestine

40 Duodenum

41 Gall Bladder Cystic duct Bile duct – empties into small cystic duct
Secrete bile for duodenum digestion Bile – Right and Left hepatic ducts to common cystic duct to Gall bladder for storage From GB to bile duct to duodenum

42 Gall Bladder

43 Pancreas Exocrine gland – produces most enzymes for digestion in small intestine Endocrine function = produce hormones that regulate levels of sugar in the blood Main pancreatic duct

44 Gall Bladder and Pancreas

45 Pancreas

46 Large Intestine Most material has been digested by the time it reaches LI 12-24 hours in large bowel Little breakdown Performs some absorption, especially water Components Ascending colon Transverse colon Descending colon Sigmoid to rectum and anus

47 Large Intestine

48 Large Intestine

49 Cecum and appendix Cecum is a small sac (blind pouch)
Valve prevents a back up of fecal matter to ileum Appendix Lymph tissue neutralizes bacteria Diverticulosus – a small outward herniation of colon, especially sigmoid Diverticulitis – infection with leaks into peritoneal cavity may lead to peritonitis

50 Anal Canal ANS balance between defecation or not
PNS = increase movement SNS = decrease Voluntary control via external sphincter muscles

51 Anal Canal

52 Defecation

53 Liver Largest gland in the body (1.4 kg – 3 lbs.) Produces bile
Stored in GB Emulsifies fats Involved in metabolism Diaphramatic and visceral surface Right and left lobes Porta hepatis = major vessels and nerves Right and left hepatic ducts, common bile, common

54 Liver

55 Liver

56 Liver

57 Liver

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