Digestive System

Word Parts

• lle/o: Ileum

• Jejun/o: Jejunum

• Lapar/o: Abdomen

• -lith: Stone

• Pancreat/o: Pancreas

• -pepsia: Digestion

• Phag/o: Eating or swallowing

• -phagia: Eat or swallow

• Proct/o: Anus and rectum

• Pylor/o: Pylorus

• Rect/o: Rectum

• -scope: Instrument used for viewing

• -scopy: Visual examination

• Sial/o: Salivary glands

• Sigmoid/o: Sigmoid colon

• Stomat/o: Mouth

• Abdomin/o: Abdomen

• Dent/i; dent/o: Teeth

• Bucc/o: Cheek

• Duoden/o: Duodenum

• Cheil/o: Lip

• -emesis: Vomit

• Enter/o: Intestine

• Esophag/o: Esophagus

• Gastr/o: Stomach

• Gingiv/o: Gums

• Gloss/o: Tongue

• Hepat/o: Liver

• Chol/e; chol/o: Bile, gall

• Cholangi/o: Bile duct

• Cholecyst/o: Gallbladder

• Choledoch/o: Common bile duct

• Col/o; colon/o: Colon

Introduction

• Digestive system includes the alimentary canal and several accessory organs.

• The alimentary canal, also known as the gastrointestinal tract, starts at the mouth and ends at the anus.

• Three main functions:

  • Digestion

  • Absorption

  • Elimination

Digestion

• Prepares food for cellular intake.

• Nutrients are broken down through mechanical and chemical processes.

• Nutrients must be small enough to be absorbed into circulation.

• Digestion occurs in the digestive tract.

• Food is moved through the digestive tract by peristalsis.

The Mouth to the Stomach

• Digestion begins in the mouth.

• Mastication (chewing) breaks up food.

• Teeth, tongue, lips, cheek, and palate help to break up food and mix it with saliva.

• Moistened food passes:

  • Into the pharynx

  • Through the esophagus

  • Into the stomach

The Mouth

• Parts of the Mouth

  • Upper lip

  • Gingiva (gum)

  • Cuspid

  • Premolars

  • Pharynx

  • Hard palate

  • Soft palate

    • Uvula

    • Palatine tonsil

  • Molars

  • Lower lip

  • Incisors

Saliva

• Produced in the salivary glands:

  • Parotid

  • Submandibular

  • Sublingual

• Saliva lubricates the mouth and contains digestive enzymes.

Accessory Organs of the Mouth

• Parotid gland and duct

• Submandibular gland and duct

• Sublingual gland and ducts

• Tongue

The Mouth to the Stomach

• Churning of the stomach further breaks down food by:

  • Mixing with the enzyme pepsin and Hydrochloric Acid.

The Small Intestine

• Digested nutrients are absorbed into circulation.

• Absorption is aided by villi, which are small projections in the intestinal lining.

• Sections of the small intestine:

  • Duodenum

  • Jejunum

  • Ileum

The Large Intestine

• Undigested food, water, and digestive juices pass into the large intestine.

• The colon flexes and changes direction through the following sections:

  • Cecum

  • Ascending colon

  • Transverse colon

  • Descending colon

The Large Intestine

• Water is reabsorbed, and feces are formed.

• Waste material passes into the sigmoid colon.

• Waste is stored in the rectum and eliminated through the anus.

Accessory Organs

• Salivary glands: Secrete enzymes that begin the digestion of starch.

• Liver: Secretes bile to break down fats.

• Gallbladder: Stores bile until needed.

• Pancreas: Produces a mixture of digestive enzymes.

Accessory Organs location

• Diaphragm

• Liver

• Gallbladder

• Cystic duct

• Duodenum

• Pancreas

• Common hepatic duct

• Pancreatic duct

• Common bile duct

Liver

• Largest organ.

• Produces bile, which breaks down fat globules.

• Releases Bilirubin

• Maintains normal blood glucose levels.

• Manufactures blood proteins for blood clotting.

• Removes toxins from the blood.

• Makes cholesterol.

Cholesterol

• Produced in the liver.

• When you eat carbohydrates (highly processed), your body releases insulin, which tells your liver to make cholesterol.

• Eating highly processed carbohydrates plays a role in high cholesterol levels.

• When you consume > 60% of your daily calories from carbohydrates, it increases the production of cholesterol, increasing your levels.

Gallbladder

• Stores bile until food is in the stomach and duodenum.

Pancreas

• Produces digestive enzymes:

  • Amylase: Digests starch

  • Protease: Digests proteins

  • Lipase: Digests fats (after bile has broken down the fat globules)

• The pancreas also secretes insulin to regulate blood sugar.

Bilirubin

• Formed in the spleen after RBC and Hemoglobin breakdown.

• Travels to the liver and becomes water-soluble.

• Bilirubin combines with bile (which breaks down fats) and enters the duodenum (small intestine).

• Bacteria in the colon degrades the bilirubin, giving stool its brown color.

• Bilirubin and bile leave the body in the feces.

• When the liver is damaged, bilirubin remains in the bloodstream, causing jaundice.