University:
Central Michigan University
Course:
BIO 151 | Human Biology
Academic year:

2021
Views:

285

Pages:

15
Author:

Vokboageecogsoyb

Digestion • Phases Include 1. 2. 3. 4. 5. Ingestion Movement Mechanical and Chemical Digestion Absorption Elimination Digestion • Types – Mechanical (physical) • Chew • Tear • Grind • Mash • Mix – Chemical • Enzymatic reactions to improve digestion of – Carbohydrates – Proteins – Lipids Mouth • Teeth mechanically break down food into small pieces. Tongue mixes food with saliva (contains amylase, which helps break down starch). • Epiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing food from entering it. Esophagus • Approximately 10” long • Functions include: 1. Secrete mucus 2. Moves food from the throat to the stomach using muscle movement called peristalsis • If acid from the stomach gets in here that’s heartburn. Stomach • J-shaped muscular bag that stores the food you eat, breaks it down into tiny pieces. • Mixes food with digestive juices that contain enzymes to break down proteins and lipids. • Acid in the stomach kills bacteria. • Food found in the stomach is called chyme. Small Intestine • Small intestines are roughly 7 meters long • Lining of intestine walls has finger-like projections called villi, to increase surface area. • The villi are covered in microvilli which further increases surface area for absorption. • Bile aids in the chemical digestion of lipids • Enzymes continue to digest carbohydrates, lipids and proteins. Small Intestine • Nutrients from the food pass into the bloodstream through the small intestine walls. • Absorbs: – 80% ingested water – Vitamins – Minerals – Carbohydrates – Proteins – Lipids • Secretes digestive enzymes Large Intestine • About 5 feet long • Continues to absorb water • Rectum (short term storage which holds feces before it is expelled). Large Intestine Absorbs more water – Concentrate wastes – Accessory Organs • Not part of the path of food, but play a critical role. • Include: Liver, gall bladder, and pancreas Liver • Directly affects digestion by producing bile – Bile helps digest fat • filters out toxins and waste including drugs and alcohol Gall Bladder • Stores bile from the liver, releases it into the small intestine. • Fatty diets can cause gallstones Pancreas • Produces digestive enzymes to digest fats, carbohydrates and proteins • Regulates blood sugar by producing insulin How’d you do? • • • • • • • Green: Esophagus Red: Stomach Pink: Small Intestine Brown: Large Intestine Purple: Liver Green: Gall Bladder Yellow: Pancreas

The Human Digestive System Slides

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