Digestive Tract

GI (Gastrointestinal) Tract or Alimentary Canal

“How French Fries become Feces”

VocabularyPurloin (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

Oral Cavity

Food is placed into the Oral Cavity for ingestion

Teeth break down food into smaller pieces, this process is known as mastication.

Teeth

Medical Root (Dento)

There are 32 adult teeth

Made out of Calcium

3 TypesIncisors- all purpose teeth located in the front

Canines-sharp “fang” teeth used for tearing meat

Molars- in the back, used for grinding

Major Features of the Mouth

UvulaSoft tissue which hangs from the Soft Palate

FrenulumFold underneath the tongue which helps keep it in place.

Palate Superior aspect of mouthServes as the roof between the nasal cavity and the oral cavity.Hard Palate is most anterior, followed by Soft Palate

Palatine TonsilsLocated in back of mouthTheir job is to attract pathogens

Salivary GlandsOnce food is in mouth, the brain secretes saliva to assist with the chemical breakdown of food. 3 Salivary Glands (“Sialo”)

ParotidLocated in front of the ears

SublingualLocated under the tongue

SubmandibularLocated 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

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. NasopharynxMost superior; not relevant in the digestive tract

2. OropharanxPosterior part of oral cavityFood is pushed to the oropharynx by the tongue

Pharynx (Throat) (cont)3. Laryngopharynx

Most inferior part of throatHere, 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 breathingOnce food is eaten it is called a Bolus

Diagnostic Tools of Upper GI Tract

Barium SwallowBarium “lights up” when drunk.

Xrays are then taken

EndoscopyA camera (endoscope) is inserted into the mouth.

It is guided down the pharynx, esophagus, and stomach to:

Take pictures

Remove suspicious items

Video

Scissors in Throat!!

EsophagusTube that carries bolus (food) from throat to stomachEsophagus 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.

Esophagus

Stomach =“Gastro”Stomach is mainly a food reservoir and “pacer” for the small intestines.It is in the upper left quadrantHCL acid is released here to chemically break the bolus downPepsin, 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/exitingSometimes, the HCL acid escapes into the esophagus and causes GERD (aka reflux or heartburn)

Stomach is divided into 3 major regionsOnce it enters the stomach the bolus lies in the 1) Fundus.

Most superior part of the stomachMostly full of air

Stomach (cont)2) Body

The central part of the stomach

3) PylorusMost distal or end part of stomachPyloric 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 CurvaturesThe Greater Curvature

Bottom curve of the stomachThe Lesser Curvature

The top curve of the stomach

BezoarHairballs lodged in stomach that are never digested.

The OmentumDrape of fat that extends from the Greater Curvature down over the intestines

The Stomach

Stomach lined with Hydrochloric Acid (HCL)

Assist with chemical breakdown of bolusStomach also produces this mucous to protect the stomach lining from burningPeptic Ulcers

H. Pylor bacteria disrupts balanceHCL acid begins burning through the rugae

PerforationWhen HCL burns through the stomach lining completely and acid drips into abdominal cavity.Causes: Stress, poor diet, eating disorders, etcShow Video

Peptic Ulcer

Upper GI study with Barium

Small Intestines or Small Bowel

Main site of digestionSits in the middle of abdomen surrounded by the large intestinesIntestines kept together by a web of fat called the Mesentary.

Consists of 3 partsDuodenum-1 ft long

– Receives the digestive juices from the pancreas and liver

Jejunum-8 ft longIleum-12 ft long

Pig Small Intestines

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.

Pop Quiz

Define the following on a piece of paper.

Palate

Peristalsis

Pyloric Sphincter

Villi

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.

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 ligamentOn the posterior aspect are the Caudate and Quadrate lobesThe liver produces bile, an enzyme which breakdowns fatInside 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.

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.

Large Intestines

Once food is digested by villi in small intestines, the unabsorbed “food” enters the large intestinesThe 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.

The Intestines with Barium

Pig Large Intestines

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

Large Intestines (cont)

Large Intestines consist of 3 parts

Cecum

Colon

Rectum1. Cecum (RLQ)

Small pouch of Lower Intestines that connects with ileum of small intestines

The appendix hangs from it

Large Intestines (cont)2. Colon

The Colon has 4 sections.A. Ascending Colon

Rt side of abdomenStops at Hepatic (Liver) Flexure

– Flexure holds up right side of colon

B. Transverse ColonRuns along the superior aspect of abdomenStops at Splenic (spleen) Flexure

– Flexure holds up left side of colon

C. Descending ColonLt side of abdomen

D. Sigmoid Colon“S” shaped colon that runs from descending colon posteriorly to the rectum.

Large Intestines

3. RectumFinal part of large intestines

“Poop” reservoir holding feces to be defecated

AnusAnal sphincter

Site of hemorrhoids

Digestive Medical Roots

Gingivo-gums Lingo/Glosso- TongueSialo-salivary glandsPharyngo-throatEsophago-EsophagusGastro-StomachEntero-IntestinesChole-BileCholecyst-Gall BladderCholelithiasis-Gall StonesColo-ColonRecto-Rectum

algia=painitisectomyTomy= surgical openingOmaLogyGraph=radiographic study of

Med Terms

Anorexia-lack of appetiteEmesis- VomitingHematemesis- bloody vomitHematochezia- bloody fecesDefecation- the process of “pooping”Dysphagia- Difficulty swallowingAphagia- Inability to swallowIncontinence- Inability to hold one’s feces or urine.Cholecystitis- Inflammation of gall bladderCholecystectomy- Removal of gall bladderColostomy/Ileostomy Bag- “pooping out” of a bag attached to your stomach.Proctology- the branch of medicine dealing with the colon, rectum, and defecation problems..

More Terms…

Enema- placing a water solution in your anus to cleanse the colon.To Eructate- the act of belchingTo Expectorate- the act of spitting or coughingHalitosis- bad breathVolvulus- the twisting of your intestinesPica- a craving to eat inanimate objectsTo intubate (v)- to forcefully open the throatTo aspirate (v)- the process of removing food when stuck in the throat, normally done by suction.Flatus- gasDeglutition- the act of swallowing

Abbreviations

A.S.= Left EarA.D.= Right EarATC= Around the clockNKDA= No Known Drug AllergiesN/V= Nausea & VomitingQ2h= Every 2 HoursQ4h= Every 4 HoursSOB= Shortness of Breath