The digestive system

[ul] [li]Organs like the [b]Pancreas[/b] and the [b]Salivary Glands[/b] release digestive juices to break down food[/li] [li]The [b]Stomach[/b] and the [b]Small Intestine[/b] are the main organs where food is digested [img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1485543993/mcdc7_viral_gastroenteritisthu_jpg_w1h3gw.jpg'][/li] [li][b]Enzymes[/b] increase the rate of break down of large insoluble food molecules into smaller soluble ones, as they are [b]biological catalyst[/b][/li] [li]The broken down food molecules are absorbed by the [b]Small intestine[/b] - they are small enough to pass through the [u]organs walls[/u] and into the [u]capillaries[/u]; hence into the [u]bloodstream by diffusion[/u][/li] [li]They diffuse as there is a [b]high concentration[/b] of food molecules in the gut ([u]The digestive tract commonly the small intestine[/u]), in comparison to the bloodstream, so they pass through the capillary walls - [u]down a concentration gradient[/u][/li] [li]Some substances are transported by active transport[/li] [li]As more surface area -> faster digestion, the small intestine has [b]villi[/b] ([u]small protrusions from the gut wall[/u]), upon which there are [b]microvilli[/b] (further protrusions upon the villi), and as there is a significantly larger total surface area -> the rate of diffusion/absorption is much higher as well [img src='https://res.cloudinary.com/deylrqt2d/image/upload/v1485543942/ef26d067a6db79bb99e6d7a7a0f25a8976aa9acd_zjswbh.gif'] [/li] [li]Then the absorbed food is transported around your body, by your bloodstream[/li] [li]The muscular walls of the gut squeeze the undigested food to the [b]large intestine[/b][/li] [li]This is where water from [u]undigested food[/u] is absorbed into your blood[/li] [li]The remaining material is the bulk of the [b]feces[/b][/li] [li]The feces are stored and pass through the [b]anus[/b] back into the environment[/li] [/ul] [b]Chemicals in digestion:[/b] Stomach: [ul] [li]Pepsin[/li] [li]Hydrochloric Acid[/li] [li]Gastric Juice[/li] [/ul] Small Intestine: [ul] [li]Pancreatic Juice[/li] [li]Intestinal Juice[/li] [li]Bile[/li] [/ul]