BrainPOP | Digestive System

PURPOSE: designed to break down food into smaller particles that can be used by the microscopic cells of the body.

2 types of digestion… Mechanical digestion: chewing, tearing, churning, and pushing of food by teeth (mastication), tongue & intestines Chemical digestion: enzymes/acids/bile break down and change the molecules so they are able to pass into the blood/cells

Major Structures of the Digestive System 1. Mouth (oral cavity) Site for ingestion digestion begins! Contain salivary amylase to start the digestion of carbohydrates Gleek

Food tube connecting the mouth to the stomach 2. Esophagus Food tube connecting the mouth to the stomach Peristalsis – contractions that push food down the digestive tract Epiglottis A flap of tissue that closes over the trachea when you swallow Epiglottis animation - YouTube

3. Stomach churns and mixes food you swallowed Forms chyme hydrochloric acid and pepsin begin protein digestion

Accessory Organs! (Organs that secrete substances into the digestive tract) Salivary Glands Pancreas – most enzymes for digestion are produced here (protease, more amylase, lipase) and secreted into the small intestine!!! Liver – produces bile which emulsifies fats making it possible for enzymes to reach fat molecules and break them down Gall Bladder – small organ that stores bile

4. Small Intestine most chemical digestion takes place here!! Function is to absorb nutrients into blood Villi: finger-like projections lining it increase the surface area for absorption. Contain capillaries that absorb amino acids and sugar, and lacteals (tiny lymph vessels) that absorb fats

5. Large Intestine (Colon) Main function is reabsorption of water into the body Contains E. coli bacteria that produce vitamins Feces is stored in the rectum before being removed from the body through the anus Gut Fauna