1 / 9

THE DIGESTIVE SYSTEM

THE DIGESTIVE SYSTEM. Mechanical and chemical digestion.

rolf
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

  2. Mechanical and chemical digestion • There are two types of digestion which occur in the body. Mechanical digestion is when the teeth and muscles of the stomach brake down the food so that it can be absorbed by the body.Chemical digestion is when enzymes and acids within the mouth, stomach, and small intestine brake down food into small molecules so that it can be absorbed.

  3. The mouth. • digestion begins in the mouth where food is mechanically broken down by the teeth as they chew. • Saliva contains digestive enzymes such as salivary amylase, which aids in the chemical breakdown of food. It also contains mucous, a glycoprotein which helps soften the food into a bolus(ball of chewed and moistenedfood) which aids with swallowing.

  4. The Oesophagus • The oesophagus is an organ in vertebrates which consists of a muscular tube through which food passes from the mouth to the stomach. • During swallowing food passes from the mouth intothe oesophagus and travels via peristalsis to the stomach.

  5. The Stomach • Stomach churning has the effect of assisting the mechanical disassembly which began in the mouth. • Pepsin and other digestive enzymes work in the stomach to chemically break down the food into small molecules.Food in the stomach isin semi-liquid form, which upon completion is known as chyme.

  6. The small intestine - digestion • The small intestine in an adult human measures on average about 5 meters. • The small intestine is where most chemical digestion takes place. • Most of the digestive enzymes that act in the small intestine are pancreatic enzymes secreted by the pancreas and enter the small intestine via the pancreatic duct. Bilecreated in the liver is alsosecreted into the small intestine by the gall bladder, It helps to break down fat.

  7. The small intestine - absorption • Small, finger-like structures called villi, each of which is covered with even smaller hair-like structures called microvilli improve the absorption of nutrients by increasing the surface area of the intestine. • Blood containing the absorbed nutrients is carried away from the small intestine via the hepatic portal vein and goes to the liver for filtering, removal oftoxins, and nutrientprocessing.

  8. The large intestine • The function of the large intestine is to absorb water from the remaining indigestible food matter, and then to pass useless waste material from the body. • Food products that cannot be absorbed into the body, such as cellulose, are mixed with otherwaste products from thebody and become hard and form concentrated faeces.

  9. Words you need to know! • Mechanical digestion • Chemical digestion • Salivary amylase • Mucous • Bolus • Digestive enzymes • Chyme • Pancreatic enzymes • Bile • Villi and microvilli

More Related