Digestive Tract

1. Digestive Tract GI (Gastrointestinal) Tract or Alimentary Canal “How French Fries become Feces”

2. Vocabulary • Purloin (v)- to steal; take something dishonestly • Succinct (adj)- speaking/writing in a brief and concise manner (syn. terse, pithy) • Abstruse (adj)- something which is difficult to understand • Clandestine (adj)- an action or activity that is secretive, furtive • Cabal (n)- small group of people meeting together to put in an agenda or course of action that is normally bad. • Malevolent (adj)-{malevolence-(n)}-having/showing ill-will, hatred, or evil toward someone; (syn: malicious) • Frugal (adj)- to be “cheap” or thrifty in money • Respite (n)- a short interval of relief from something stressful; “a peaceful break” • Edict (n)- a order/decree/proclamation issued by someone of authority. • Incorrigible- (adj)- unable to be corrected of bad habits or behavior

3. Oral Cavity • Food is placed into the Oral Cavity for ingestion • Teeth break down food into smaller pieces, this process is known as mastication.

4. Teeth • Medical Root (Dento) • There are 32 adult teeth • Made out of Calcium • 3 Types • Incisors- all purpose teeth located in the front • Canines-sharp “fang” teeth used for tearing meat • Molars- in the back, used for grinding

5. Major Features of the Mouth • Uvula • Soft tissue which hangs from the Soft Palate • Frenulum • Fold underneath the tongue which helps keep it in place. • Palate • Superior aspect of mouth • Serves as the roof between the nasal cavity and the oral cavity. • Hard Palate is most anterior, followed by Soft Palate • Palatine Tonsils • Located in back of mouth • Their job is to attract pathogens

6. Salivary Glands • Once food is in mouth, the brain secretes saliva to assist with the chemical breakdown of food. • 3 Salivary Glands (“Sialo”) • Parotid • Located in front of the ears • Sublingual • Located under the tongue • Submandibular • Located under the jawbone • All can become block and infected • The tongue (“linguo”) and teeth assist in the mechanical breakdown of food by masticating • The tongue is held in place by the Hyoid bone, a bone in the middle of throat. • The tongue has taste buds of sweet, sour, bitter, salty

7. Pharynx (throat) • The Pharynx is comprised of three sections, though it is one large cavity. • The last two sections are shared by the digestive and respiratory systems • 1. Nasopharynx • Most superior; not relevant in the digestive tract • 2. Oropharanx • Posterior part of oral cavity • Food is pushed to the oropharynx by the tongue

8. Pharynx (Throat) (cont) • 3. Laryngopharynx • Most inferior part of throat • Here, the throat divides into two roads. • 1. Digestive- the pharynx becomes the esophagus to take food to stomach • 2. Respiratory- the trachea (windpipe) begins to carry air to lungs. • Epiglottis- small flap that covers the trachea so food doesn’t enter it. • The epiglottis remains open at all times aside from swallowing to allow for breathing • Once food is eaten it is called a Bolus

9. Diagnostic Tools of Upper GI Tract • Barium Swallow • Barium “lights up” when drunk. • Xrays are then taken • Endoscopy • A camera (endoscope) is inserted into the mouth. • It is guided down the pharynx, esophagus, and stomach to: • Take pictures • Remove suspicious items • Video

10. Scissors in Throat!!

11. Esophagus • Tube that carries bolus (food) from throat to stomach • Esophagus looks like a deflated balloon. • “Food” passes through it like a snake eating a rat. • It isposterior to the trachea, passes between the lungs, and through the diaphragm to enter the abdominal cavity to reach the stomach. • Esophagus is lined with smooth muscle to push the “food” down. • Peristalsis is the constant involuntary movement of food throughout the GI tract. • We do not control it.

12. Esophagus

13. Stomach =“Gastro” • Stomach is mainly a food reservoir and “pacer” for the small intestines. • It is in the upper left quadrant • HCL acid is released here to chemically break the bolus down • Pepsin, an enzyme, is released to break down protein. • The Rugae muscles in stomach twist and turn to mechanically break the food down. • Bolus enters stomach through the Cardiac (aka Gastro-esophageal) sphincter • A sphincter is a valve or door that prevents contents from entering/exiting • Sometimes, the HCL acid escapes into the esophagus and causes GERD (aka reflux or heartburn) • Stomach is divided into 3 major regions • Once it enters the stomach the bolus lies in the 1) Fundus. • Most superior part of the stomach • Mostly full of air

14. Stomach (cont) • 2) Body • The central part of the stomach • 3) Pylorus • Most distal or end part of stomach • Pyloric sphincter • Door that separates stomach from small intestines • It opens and closes based on how much the intestines can digest at that time • Food becomes “chyme” when it enters the small intestines. • The Curvatures • The Greater Curvature • Bottom curve of the stomach • The Lesser Curvature • The top curve of the stomach • Bezoar • Hairballs lodged in stomach that are never digested. • The Omentum • Drape of fat that extends from the Greater Curvature down over the intestines

15. The Stomach • Stomach lined with Hydrochloric Acid (HCL) • Assist with chemical breakdown of bolus • Stomach also produces this mucous to protect the stomach lining from burning • Peptic Ulcers • H. Pylor bacteria disrupts balance • HCL acid begins burning through the rugae • Perforation • When HCL burns through the stomach lining completely and acid drips into abdominal cavity. • Causes: Stress, poor diet, eating disorders, etc • Show Video

16. Peptic Ulcer

17. Upper GI study with Barium

18. Small Intestines or Small Bowel • Main site of digestion • Sits in the middle of abdomen surrounded by the large intestines • Intestines kept together by a web of fat called the Mesentary. • Consists of 3 parts • Duodenum-1 ft long • Receives the digestive juices from the pancreas and liver • Jejunum-8 ft long • Ileum-12 ft long

19. Pig Small Intestines

20. Villi-site of absorption • Absorption takes place by microscopic cells called villi in the small intestines. • They absorb nutrients which are then whisked away by the little veins to be filtered by the liver. • Indigestible food is carried to the Large Intestines.

21. Pop Quiz • Define the following on a piece of paper. • Palate • Peristalsis • Pyloric Sphincter • Villi

22. Accessory Digestive Organs • The liver and pancreas assist in digestion by releasing digestive juices into the Duodenum. • However, chyme (food) does not enter these organs.

23. Liver • Organ responsible for “cleaning” the body and producing cholesterol and bile. • Divided into 4 lobes • Left and Right lobes are on the anterior separated by the Falciform ligament • On the posterior aspect are the Caudate and Quadrate lobes • The liver produces bile, an enzyme which breakdowns fat • Inside the bile is a yellowish product called bilirubin, which is a by-product of the destruction of old red blood cells (RBC). • Bile is stored in the gall bladder, a small pouch underneath the liver • When you eat a fatty meal the bile is released by the gall bladder to help with digestion. • The bile gets to the duodenum of the small intestines by a collection of tubes called the Biliary Tree, or “Tree of Bile” • When bile pieces become hardened they become gall stones (“cholelithiasis”) • Sometimes they get lodged in gall bladder or in biliary tree causing RUQ pain.

24. Pancreas • Largest gland in body • 3 sections • Head- Largest part closest to Duodenum • Neck • Tail- skinny part which stretches laterally • Produces 2 major things: • 1. Trypsin- an enzyme used to breakdown protein (similar to pepsin in stomach) • 2. Hormones responsible for regulating blood sugar • Insulin- secreted when sugar is too high in the blood to lower it • Glycogen- secreted when sugar is too low to raise it.

25. Large Intestines • Once food is digested by villi in small intestines, the unabsorbed “food” enters the large intestines • The large intestines is the “poop” maker • NO ABSORPTION TAKES PLACE HERE! • Feces is brown in appearance due to the mixture of bile and bilirubin. • The large intestines surround the small intestines.

26. The Intestines with Barium

27. Pig Large Intestines

28. Large Intestines • 5 feet long • Takes about 16 hours for food to pass through it. • Primary responsibility to absorb remaining water from the waste matter and then turn it into feces. • Bolus=Chyme=Feces • Flatulence is gas caused by the breakdown of food in the intestines by bacteria • Most flatulence is nitrogen, C02, and methane. • General Anatomical Features • Taeniae Coli- 3 bands of connective muscles that run throughout the large intestines that helps push the feces • Haustra- large pouches formed by Taeniae Coli

29. Large Intestines (cont) • Large Intestines consist of 3 parts • Cecum • Colon • Rectum • 1. Cecum (RLQ) • Small pouch of Lower Intestines that connects with ileum of small intestines • The appendix hangs from it

30. Large Intestines (cont) • 2. Colon • The Colon has 4 sections. • A. Ascending Colon • Rt side of abdomen • Stops at Hepatic (Liver) Flexure • Flexure holds up right side of colon • B. Transverse Colon • Runs along the superior aspect of abdomen • Stops at Splenic (spleen) Flexure • Flexure holds up left side of colon • C. Descending Colon • Lt side of abdomen • D. Sigmoid Colon • “S” shaped colon that runs from descending colon posteriorly to the rectum.

31. Large Intestines • 3. Rectum • Final part of large intestines • “Poop” reservoir holding feces to be defecated • Anus • Anal sphincter • Site of hemorrhoids

32. Gingivo-gums Lingo/Glosso- Tongue Sialo-salivary glands Pharyngo-throat Esophago-Esophagus Gastro-Stomach Entero-Intestines Chole-Bile Cholecyst-Gall Bladder Cholelithiasis-Gall Stones Colo-Colon Recto-Rectum algia=pain itis ectomy Tomy= surgical opening Oma Logy Graph=radiographic study of Digestive Medical Roots

33. Med Terms • Anorexia-lack of appetite • Emesis- Vomiting • Hematemesis- bloody vomit • Hematochezia- bloody feces • Defecation- the process of “pooping” • Dysphagia- Difficulty swallowing • Aphagia- Inability to swallow • Incontinence- Inability to hold one’s feces or urine. • Cholecystitis- Inflammation of gall bladder • Cholecystectomy- Removal of gall bladder • Colostomy/Ileostomy Bag- “pooping out” of a bag attached to your stomach. • Proctology- the branch of medicine dealing with the colon, rectum, and defecation problems..

34. More Terms… • Enema- placing a water solution in your anus to cleanse the colon. • To Eructate- the act of belching • To Expectorate- the act of spitting or coughing • Halitosis- bad breath • Volvulus- the twisting of your intestines • Pica- a craving to eat inanimate objects • To intubate (v)- to forcefully open the throat • To aspirate (v)- the process of removing food when stuck in the throat, normally done by suction. • Flatus- gas • Deglutition- the act of swallowing

35. Abbreviations • A.S.= Left Ear • A.D.= Right Ear • ATC= Around the clock • NKDA= No Known Drug Allergies • N/V= Nausea & Vomiting • Q2h= Every 2 Hours • Q4h= Every 4 Hours • SOB= Shortness of Breath