The Digestive System Bringing it In and Taking it Out
Digestive System (on sheet, not notes ) Organ System Function Organs/Parts Digestive system To extract energy and nutrients from food To eliminate byproducts Mouth Esophagus Stomach Small intestine Large intestine Mouth Esophagus Stomach Small and large intestines
Breaking Down Food (not notes) In order for food to be usable by the body it must be broken down both mechanically and chemically Mechanical breaking is like crushing or pulverizing so that it is in small pieces Chemical breaking is breaking the bonds that hold molecules together, turning them into forms our body can use
Mouth (notes) Function: Beginning the break down of food Teeth do mechanical break down, saliva (spit) is for chemical break down If you ever want to test this for yourself, spit on a piece of bread: Wait a little while and then eat the piece of bread you spit on it will taste sweet. This is because your saliva contains proteins that break down the complex sugars in bread into simpler ones.
Teeth (not notes) Mammals (including humans) are champions when it comes to teeth. Below are a few things we can do that other vertebrates can t: 1. Chew. Fish, reptiles, and birds all cannot chew to break down their food and must swallow it whole.
Chewing continued (not notes) Because mammals chew so much, we had to make sure the food didn t fall out of our mouths. Hence: cheeks! No cheeks here! Cheeks? Check.
Teeth (not notes) 2. Specialized teeth. Mammals have a whole Swiss army knife of teeth in their mouths. Scary teeth, but all the same type Mammals: Molars for grinding, premolars for shredding, canines for piercing and incisors for clipping
Teeth (not notes) 3. Baby teeth. We have one set of teeth when we re young and another when we are older.
Esophagus (notes) Function: transport food to stomach The esophagus is lined with muscle and actively pushes food along The technical term for this process is peristalsis. Peristalsis is so strong that you can swallow while upside down.
Stomach (notes) Function: Completing the breaking down of food Churning does mechanical break down, acid (HCl) and proteins do chemical break down Contrary to popular belief, the purpose of acid in the stomach is primarily to stop bacteria and create an favorable environment for your digestive proteins.
Cow stomachs (not notes) Grass is tough to break down, so cows (and similar organisms) have large guts However, they do not have four stomachs. They have four separated compartments in their stomach instead.
Crops and Gizzards (not notes) Crop: an expanded area of the throat that acts as a temporary storage area. Many organisms such as birds and bees/ants have this, but mammals do not. Gizzard: the lower half of the stomach in a bird. Since they can t chew, they have a very strong grinding stomach. Many birds swallow grit or rocks to help grind the food
Gastroliths (not notes) Gastrolith literally means stomach rock Smoothed rocks found dinosaur fossils where the stomach used to be This indicates that dinosaurs probably also had gizzards
Small intestine (notes) Function: absorption of nutrients The surface of the small intestine is covered in small ridges to give it more chances to take in nutrients
Small intestine (not notes) The small intestine is so folded on itself that if spread out it covers 250 square meters, which is approximately the size of a tennis court
Large Intestine (notes) Function: Reabsorb water used in digestion Large intestine and colon Large intestine in cross section
A Food s Perspective https://www.youtube.com/watch?v=_qy wscalnng
Journey Through the Gut (assignment) Get a blank piece of paper and put your name and period at the top Title it Journey Through the Gut From the perspective of a tiny traveler, describe the experience of passing through the gut of another person You must name all the major parts (mouth, esophagus, stomach, small intestine, large intestine) as you go Describe the visuals! I see white pillars of Requirements: ½ page