BI 252

• GIT (gastrointestinal tract) organs and functions

  • Oral Cavity
  • Pharynx
  • Esophagus
  • Stomach
  • Small Intestine
  • Cecum
  • Appendix
  • Large Intestine
• Oral Cavity


  • Enables mechanical digestion of ingested food
  • Includes the cheeks, tongue, and palate
  • It is the entrance to the GI tract
• Pharynx


  • Receives food from the mouth, and air from both the mouth and the nasal cavities
  • When food enters the pharynx, involuntary muscle contractions close off the air passageways
• Esophagus


  • Transports food from the pharynx to the stomach via peristaltic waves
• Stomach


  • Continues the jobs of mechanical and chemical digestion
  • Holds the ingested food and releases it slowly into the small intestine, where digestion is completed and absorption begins
• Small Intestine


  • Duodenum
  • Jejunum
  • Ileum
• Duodenum


  • Receives chyme from the stomach and mixes it with bile and pancreatic juice
• Jejunum


  • Performs most of the final digestion and absorption of dietary nutrients
• Ileum


  • The final and longest segment of the small intestine, which runs between the jejunum and the cecum of the large intestine
• Cecum


  • A pouch-like structure that forms the beginning of the large intestine
  • Lies between the ileum of the small intestine and the ascending colon of the large intestine
• Appendix


  • Serves as a bacterial reservoir and a small cohort of every bacterial population in the colon is represented here
• Large Intestine


  • Transverse Colon
  • Ascending Colon
  • Descending Colon
  • Sigmoid Colon
  • Rectum
  • Anus
• Transverse Colon


  • The portion of the colon that lies between the ascending colon and the descending colon
  • Runs across the upper portion of the abdominopelvic cavity from right to left
• Ascending Colon


  • The region of the colon between the cecum and the transverse colon
  • Runs upward in the right side of the abdominopelvic cavity
• Descending Colon


  • The portion of the colon that runs down the left side of the body
  • Connects the transverse colon to the sigmoid colon
• Sigmoid Colon


  • The final region of the colon, which connects the descending colon to the rectum
• Rectum


  • Functions to hold feces waiting to excrete them
• Anus


  • The opening at the end of the large intestine after the rectum
  • The waste from digestion (stool, or poop) leaves the body through the anus when you have a bowel movement
• Accessory organs and functions

  • Teeth
  • Tongue
  • Salivary Glands
  • Liver
  • Gallbladder
  • Pancreas
• Teeth


  • Used to tear, grind, and otherwise mechanically break down food
• Tongue


  • Facilitates ingestion, mechanical digestion, sensation (of taste, texture, and temperature of food), swallowing, and language
• Salivary Glands


  • Parotid Gland
  • Submandibular Gland
  • Sublingual Gland
• Parotid Gland


  • Secrete serous saliva containing amylase into the roof of the mouth
• Submandibular Gland


  • Secretes mixed saliva (part serous and part mucous) into the floor of the mouth
• Sublingual Gland


  • Secretes mucous saliva into the floor of the mouth
• Liver


  • Secretes bile and adjusts nutrient concentrations in the blood
• Gallbladder


  • Stores and concentrates bile, and secretes it into the common bile duct via the cystic duct
• Pancreas


  • Produces pancreatic juice, which contains digestive enzymes and bicarbonate ions, and delivers it to the duodenum
• Movements in GIT


  • Mixing Movements
  • Propelling Movements
• Mixing Movements

  • Stomach churning or intestinal segmentation, mix food or chyme with digestive secretions, such as enzymes, hydrochloric acid and buffers
• Propelling Movements

  • Take the form of peristalsis, a wave of muscle contraction that transports food or chyme down the GI tract
• Peritoneum

  • Parietal Peritoneum
  • Visceral Peritoneum
• Parietal Peritoneum

  • The outer layer of the peritoneum
• Visceral Peritoneum


  • The inner layer of the peritoneum
• Peritoneal folds


  • The Lesser Omentum
  • The Greater Omentum
  • The Transverse Mesocolon
  • Mesenteries
• The Lesser Omentum


  • A vertical sheet that hangs down from the inferior edge of the liver, typing it to the superior edge of the stomach
• The Greater Omentum


  • Hangs down from the inferior surface of the stomach, covering the intestines
• The Transverse Mesocolon


  • Anchors the transverse colon of the large intestine to the posterior wall of the abdominal cavity
• Mesenteries


  • Perform the same function for the small intestine, suspending each fold from the posterior abdominal wall
• Omenta


  • The stomach is held in place by the lesser omentum, which extends from the liver to the lesser curvature
  • The greater omentum, which runs from the greater curvature to the posterior abdominal wall