1 / 19

The Digestive System

Explore the phases of digestion, including mechanical and chemical processes, in the digestive system. Learn about the organs involved, such as the mouth, esophagus, stomach, small intestine, and large intestine, along with their functions and the role of accessory organs like the liver, gallbladder, and pancreas. Discover interesting facts about digestion and the body's defense mechanisms.

dhutchins
Download Presentation

The Digestive System

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Digestive System SNC2D

  2. Phases of Digestion • Mechanical (physical) • Chew • Tear • Grind • Mash • Mix • Chemical • Enzymatic reactions to improve digestion of • Carbohydrates • Proteins • Lipids • Phases Include • Ingestion • Movement • Mechanical and Chemical Digestion • Absorption • Elimination

  3. The Digestive Tract The Digestive tract is… • a series of hollow organs which may be thought of as a long twisting tube connecting the mouth to the anus, and other organs that produce or store chemicals that help break down or absorb food.

  4. The Mouth Digestion begins in the mouth where an enzyme (a chemical that speeds up other chemical reactions) in the saliva produced by the salivary glands start to break down those carbohydrates known as starches. This enzyme is called amylase.

  5. The Mouth Cont’d • Epiglottis is a flap-like structure at the back of the throat that closes over the trachea preventing food from entering it. • Teeth mechanically break down food into small pieces. Tongue mixes food with saliva (contains amylase, which helps break down starch).

  6. Esophagus • Approximately 10” long • Functions include: • Secrete mucus • Moves food from the throat to the stomach using muscle movement called peristalsis • If acid from the stomach gets in here that’s heartburn.

  7. Peristalsis Once the food is swallowed, it is moved through the digestive tract by peristalsis, involuntary muscle contractions triggered by the nervous system.

  8. To The Stomach Food travels down the esophagus to the stomach. Between the esophagus and the stomach there is a muscle called the lower esophageal sphincter, which opens to let food pass through. If it opens when it shouldn't’t, you get acid reflux (heartburn).

  9. In the Stomach Glands in the stomach lining produce stomach acid and an enzyme to break down proteins. A thick layer of mucus helps protect the lining of the stomach from its own acids. Bacterial infections can thin the mucus so that the stomach eats away at its own lining: this is an ulcer.

  10. 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. • Muscle action of the stomach mixes the food with the digestive juices, and this mixture is then emptied into the small intestine through the pyloric sphincter.

  11. The Small Intestine The first part of the small intestine, where the chemicals produced by the other organs enter the digestive process, is called the duodenum. Nutrients from the food pass into the blood stream through the small intestine walls. Absorbs :- 80 % of ingested water - Vitamins - Minerals - Carbs - Proteins - Lipids

  12. The Small Intestine The small intestine is roughly 7 meters long, folded into fingerlike projections called villi. This folding increases the surface area of the small intestine through which food molecules are absorbed into the bloodstream. Villi are covered in microvilli which further increases surface area for absorption!

  13. The Large Intestine (colon) Is about 5 ft long, accepts what small intestine don’t absorb Functions include - bacterial digestion (fermenting carbohydrates and protein breakdown ) • Absorption of water • Concentrating Wastes

  14. Accessory Organs • Not part of the path of food, but play a critical role. • Include: Liver, gall bladder, and pancreas

  15. Liver • Directly affects digestion by producing bile • Bile helps digest fat • filters out toxins and waste including drugs and alcohol

  16. Gall Bladder • Stores bile from the liver, releases it into the small intestine. • Fatty diets can cause gallstones

  17. Pancreas • Produces digestive enzymes to digest fats, carbohydratesand proteins • Regulates blood sugar by producing insulin

  18. The Body’s Defences The digestive system’s first defence against contaminants is vomiting, which can forcibly remove contents from the middle of the small intestine and up. Really, you don’t want any images here.

  19. Fun Facts • HOW LONG ARE YOUR INTESTINES? At least 25 feet in an adult. Be glad you're not a full-grown horse -- their coiled-up intestines are 89 feet long! • Food drying up and hanging out in the large intestine can last 18 hours to 2 days! • In your lifetime, your digestive system may handle about 50 tons!!

More Related