Digestive Tract

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Digestive Tract

• GI (Gastrointestinal) Tract or Alimentary Canal
• How French Fries become Feces

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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

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Oral Cavity

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

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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

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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

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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

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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

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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 doesnt 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

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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

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Scissors in Throat!!
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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 is posterior 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.

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Esophagus
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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

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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

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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

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Peptic Ulcer
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Upper GI study with Barium
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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

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Pig Small Intestines
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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.

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Pop Quiz

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

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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.

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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.

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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.

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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.

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The Intestines with Barium
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Pig Large Intestines
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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.
• BolusChymeFeces
• 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

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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

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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.

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Large Intestines

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

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Digestive Medical Roots

• 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

• algiapain
• itis
• ectomy
• Tomy surgical opening
• Oma
• Logy
• Graphradiographic study of

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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 ones 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..

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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

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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