1. Created by: Jamie Haff Instructed by Jan Clifton Summer 2010 Ivy Tech Community College Aphy 102-20F

2. Lonnie is going on a picnic for lunch today! He’s very excited to go now, but how will he obtain enough energy to complete his afternoon superhero activities? How does Lonnie’s body get energy from food? All of our bodies are experts at transforming food into energy! From the very second you put food into your mouth it is being broken down into bits and pieces so tiny that even your cells can use them! Depending on how hungry you are you might even start salivating when you smell food!

3. What exactly will Lonnie be eating? Lonnie’s favorite superhero energy treat is a PBJ with a glass of milk! We will follow his picnic-time PBJ through his body as Lonnie digests it and uses the byproducts to fuel his superpowers! Bread Peanut Butter Jelly Milk Nutrition Labels on the bread, peanut butter, jelly, and milk will help us determine what is really going into Lonnie’s body!

4. The Mouth and Teeth As you probably know, we insert food into our mouths to eat. The mouth is the beginning of the Alimentary Canal, which includes all of the organs involved in the process of digesting and eliminating our food. Our mouths begin breaking up our food into small particles and mix them with saliva. We use all 32 of our teeth in the process of biting or tearing off food and chewing. While chewing, we move our tongue around our mouths to mix our food with saliva. Salivary Glands Each of us have three major salivary glands including the parotid, submandibular, and sublingual glands. These glands excrete saliva into our mouth which begins the process of digesting the carbohydrates found in all four ingredients of Lonnie’s meal!

5. The Swallowing Mechanism There are three steps to swallowing: 1. This step involves chewing food and mixing it with saliva, creating bolus. The tongue then rolls the bolusinto a mass and forces it into the pharynx. 2. The pharynx closes off your breathing passages and opens up the esophagus at the same time, thereby forcing our food into the esophagus. 3. This stage triggers peristalsis, which are waves of muscle contractions, to help the esophagus push the food downwards to the stomach. The Esophagus The esophagus provides a passageway for food, beginning at the pharynx and ending at the stomach. Peristaltic muscle contractions push the food from the top of the esophagus down and into the stomach.

6. The Stomach The stomach has four areas: the cardia, the fundus, the body, and the pylorus. Food travels through the stomach from the first to the last of these while being exposed to a powerful gastric secretion called pepsin that breaks down protein. This means most of Lonnie’s milk, bread, and peanut butter will be digested here. Fun Facts! Most of us associate hunger with our stomach being empty but do not realize it is actually a hormone called ghrelin, which the stomach excretes, that triggers our hunger. Leptin, on the other hand, suppresses our hunger when we have attained a sensation of fullness. Did you know that about 80% of taste is smell? This is why we cannot taste things when our noses are blocked up and we can’t smell! Our senses can and do affect our digestion in multiple ways!

7. The Small Intestine Our small intestine is really where most of the digestive action happens! The duodenum begins the small intestine, the middle of the small intestine is called the jejenum, and the ileum is what we call the end portion of the small intestine. The small intestine receives the food product from the stomach, now called chyme, completes the digestion of its nutrients, absorbs the products of digestion so the rest of the body can get them, and transports the remainder to the large intestine. The small intestine secretes many enzymes which will break down whatever protein is left from Lonnie’s meal as well as the rest of the carbohydrates and even the fat found in Lonnie’s milk, bread, and peanut butter! But the small intestine cannot do all of this work by itself – it has a lot of help!

8. The Liver and Gall Bladder Your liver plays a major part in your digestion even though no food actually passes through it. Liver secretes substances into the small intestine that help mainly with the digestion of protein but also with carbohydrates and fat! In fact, the liver is digesting a pretty decent portion of Lonnie’s meal! The liver also produces a substance called bile. This bile is sent to the gall bladder to be stored for use. When the small intestine needs help digesting fat, the gall bladder secretes bile into the duodenum of the small intestine.

9. The Pancreas Surprisingly, the pancreas is an important part of digestion! Whereas the mouth only secretes one, the stomach two, and the small intestine four enzymes to help with digestion, the pancreas secretes FIVE! And to think the pancreas is more well known for the role it plays in the disease called diabetes than its role in digestion. The enzymes the pancreas secretes assist in digesting carbohydrates, proteins, and fats. The pancreas, in addition to the liver and gall bladder, secretes its enzymes into the small intestine. There, they help digest another portion of Lonnie’s meal!

10. The Large Intestine, Rectum, and Anus The large intestine is also referred to as the colon. By now, the chyme which entered the small intestine has been robbed of all nutrients that have been sent out to energize the body. All that is usually left is water, electrolytes, and waste products. The large intestine absorbs the water and electrolytes and presses the rest of the waste material together to make feces. These feces then travel the rest of the path of the large intestine and through the rectum which pushes the feces out of theanus. The anus opens to the outside of the body and rids us of these waste products.

11. The Kidneys Urination and Elimination Urination is the process of expelling our liquid wastes from our body. The micturitionreflex helps us know when we must go. Urine is composed mainly of water, nitrogen wastes, and some salts but has very small amounts of other contents as well. Elimination is the process of expelling our solid wastes from our body. The defecationreflex helps us go when we need to. Feces are composed of water, some electrolytes, mucus, bacteria, and materials not digested or absorbed. In both cases, you must look out for things that should not be in your excrement such as blood! The kidneys help to regulate the volume, composition, and pH of body fluids. They do this by removing wastes from the blood using a process called glomerular filtration. This process filters all of the body’s internal fluids continuously and moves the wastes into the bladder, which we expel as urine.

12. In the future, Lonnie will have to watch out for ulcers from eroded tissues due to escaping digestive juices, polyps which may grow inside of his digestive organs and block the proper flow of food, and allergic reactions to certain foods that could cause a variety of problems for him. But for now, Lonnie has had his superhero lunch and is off with his friends doing his superhero afternoon activities!