Major+Functions

= Functions: = = The Digestive System... = =1. Passes the molecules into blood to be carried through the body. = =2. makes food litttle into molecules that the body can absorb. = =3. Works to eliminate solid wastes from the body. = media type="youtube" key="08VyJOEcDos" width="425" height="350" =Digestive system is all about getting food into your body, digesting the food, absorbing the nutrients you need, and eliminating the materials you don't need. All animals have one sort of digestive system or another. Why? Anything that eats another creature, must have a way of bringing nutrients in and getting rid of what they don't need. =

=Essentially, the digestive system is a very long tube that twists throughout the body as it goes from the mouth to the rectum. =

media type="custom" key="19043950" =The main hormones that control digestion functions are: gastrin, secretin, and cholecystokinin (CCK). =

=These hormones are produced and liberated by cells in the mucosa of the stomach and small intestine. These are liberated into the blood of the digestive tract, travel back to the heart, through the arteries, and return to the digestive system where they make digestive juices and cause organ movement. = media type="custom" key="19044164" =Two nerves help control the action of the digestive system: Extrinsic , or outside, and intrinsic , or inside. =

=1.Extrinsic nerves: <span style="font-family: Verdana,Geneva,sans-serif;"> come from the brain or the spinal cord to the digestive organs. They release two chemicals, acetylcholine and adrenaline. Acetylcholine causes the muscle layer of the digestive organs to squeeze with force and increase the “push” of food and juice through the digestive tract. It also causes the stomach and pancreas to produce more digestive juice. Adrenaline has the opposite effect. It relaxes the muscle of the stomach and intestine and decreases the flow of blood to these organs, slowing or stopping digestion. =

=<span style="color: #0000ff; font-family: Verdana,Geneva,sans-serif;">2.Intrinsic nerves: <span style="font-family: Verdana,Geneva,sans-serif;"> make up a very dense network integrated in the walls of the esophagus, stomach, small intestine, and colon. The intrinsic nerves are induced to act when the walls of the organs are stretched by food. They liberate many different substances that speed up or delay the movement of food and the production of juices by the digestive organs. = = =

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