The document summarizes the key parts and functions of the human digestive system. It describes the 30 foot long gastrointestinal tract starting from the mouth and ending in the anus. It details the main sections including the oral cavity, esophagus, stomach, small and large intestines. The three main functions are digesting foods, absorbing nutrients, and eliminating waste. Accessory organs that help digestion include the liver, gallbladder and pancreas.

1. Anatomy and Physiology Digestive System

2. Gastrointestinal System (GI) 30 ft of muscular tube called gut or alimentary canal or gastrointestinal tract( stretches between the mouth and anus) Sections Include: Oral Cavity, Pharynx, Esophagus, Stomach, Small Intestine, Colon The accessory organs are: Liver, gallbladder, Pancreas, Salivary Gland

3. Three Main Functions Digesting Foods Absorbing Nutrients Eliminating Waste

4. Oral Cavity Food enters the mouth, where it is broken down by the teeth. The tongue mixes the food with saliva, to make it easier to swallow. Saliva contains enzymes that breakdown carbohydrates and contains a slippery lubricant that makes food traveling down the esophagus easier. The tongue has taste buds that help distinguish: Bitter, sweet, sour, or salty foods Palate is the roof of the mouth

5. Oral Cavity (Continue) Uvula hangs from the flexible posterior portion, serves two functions: Speech production and gag reflex Swallowing cause the epiglottis to cover the larynx to prevent food from entering the lungs The cheeks and lips are the anterior opening.

6. Oral cavity (Teeth) First stage of digestion Front Teeth: bite, tear, cut food into smaller pieces Cutting teeth: Incisors, Cuspids, Canines Grinding teeth: Bicuspids, premolars, molars; these teeth crush and grind food into finer pieces The tooth has two parts The Crown (visible to the teeth) covered by enamel; under the enamel is the dentin The root ( below the gums); constructed of cementum ( bony socket) and tiny periodontal ligaments Humans have two sets of teeth: Deciduous teeth( baby teeth) and Permanent teeth

7. Pharynx When swallowing food, food enters the oropharynx, then through the laryngopharynx Epiglottis flap close to cover the larynx and trachea, so food do not enter the respiratory tract Food continues down the esophagus by peristalsis ( wavelike muscular contractions) push food through the gastrointestinal tract

8. Stomach J-Shape muscular organ Acts as a sac that collect and churn food with digestive juices Three Regions :Fundus ( upper region), Body ( main region), Antrum ( lower region) Hydrochloric Acid secretions that come out of the mucus membranes of the rugae ( lining of the stomach). Food mixes with this to form a liquid mixture called Chyme. Sphincters controls the entry and exit of food, to ensure the food moves forward. Lower esophageal sphincter keeps food from flowing backwards Pyloric sphincter regulates the passage of food into the small intestine

9. Small Intestine Small Bowel Absorbs nutrients from food Major site of digestion 20 ft in length Three Sections: Duodenum(10-12in long), Jejunum( 8 ft long), Ileum (12 ft Long)

10. Colon Fluid left over after digestion, enters the colon Feces exits through the colon during bowel movements 5 ft long The cecum is the first three inches of the colon The sections to the colon: Ascending colon, transverse colon, descending colon, sigmoid colon Rectum, where feces is stored, leads to the anus Anal Sphincter controls the evacuation of feces; defecation

11. Accessories of the Digestive system Salivary glands: which is located in the oral cavity. Liver: process nutrients absorbed by the small intestine and detoxifies harmful substances in the body Gallbladder: Bile produced by the liver is stored here. Pancreas: Produces secretions for digestion, Buffers and Pancreatic enzymes. Produces hormones insulin and glucagon; regulates the levels of glucose in the blood

12. Pathology Aphthous ulcers Herpes Labialis Esophageal Varices Gastric Carcinoma Peptic ulcer Disease Anal Fistula Crohn’s Disease Polyposis Volvulus Inguinal Hernia

13. Diagnostic Therapeutic and Procedures Intravenous Cholecystography Bite-wing x-ray Upper gastrointestinal series Lower gastrointestinal series Bariatric Surgery Colostomy

14. Conclusion The Digestive system helps the human body absorb nutrients, and rid the body of waste. With the use of the digestive system, our food we ingest can be use to help growth development, healthy eye site and skin complexion