Digestive System- Spring 2020 PDF

The Digestive System How many parts of the digestive system can you label without researching the answers?  Introduction: The Digestive System Marylise How ‫ي‬ your ‫الخليف‬ CHAUFFETON, digestive system ‫سلطان‬, Marvin...

The Digestive System How many parts of the digestive system can you label without researching the answers?  Introduction: The Digestive System Marylise How ‫ي‬ your ‫الخليف‬ CHAUFFETON, digestive system ‫سلطان‬, Marvin worksVizuett, - EmmaJayant BryceSahewal, Joshua Plant, Quinn Shen, Michael James Busa, Caleb ross, Elizabeth Cruz, Elnathan Joshua Bangayan, Gaurav Rana, Mullaiarasu Sundaramurthy, Jose Henrique Leopoldo e Silva, Dan Paterniti, Jose Schroeder, Jerome Froelich, Tyler Yoshizumi, Martin Stephen, Faiza Imtiaz, Khalifa Alhulail, Tejas Dc, Govind Shukla, Benjamin Shannon Pinder, Srikote Naewchampa, Ex Foedus, Sage Curie, Exal Enrique Cisneros Tuch, Ana Maria, Vignan Velivela, Ibel Wong, Ahmad Hyari, A Hundred Years, eden sher, Travis Wehrman, Minh Tran, Louisa Lee, Kiara Taylor, Hoang Viet, Nathan A. Wright. The Digestive System: CrashCourse Biology #28 Check out our Patreon page: https://www.patreon.com/teded Hank takes us through the bowels of the human digestive system and explains why it's all about surface area. View full lesson: https://ed.ted.com/lessons/how-your-digestive-system-works-emma-bryce Crash Course Biology is now available on DVD! http://dft.ba/-8bCC Across the planet, humans eat on average between 1 and 2.7 kilograms of food a day, and every last scrap makes its way through the digestive system. Comprised of ten organs covering nine meters, this is one of the most complicated systems in the body. Emma Bryce explains how the different parts of the digestive system work to transform your food into the nutrients and energy that keep you alive. Like Crash Course? http://www.facebook.com/youtubecrashcourse Follow Crash Course: http://www.twitter.com/TheCrashCourse Lesson by Emma Bryce, animation by Augenblick Studios. Table of Contents Thank you so much to our patrons for your support! Without you this video would not be possible! Narat Suchartsunthorn, Joy Love Om, Gi Nam Lee, Shawn Quichocho, Simone Kidner, Anika Westburg, Dale Dualan, Barun Padhy, John Ess, Brandy Jones, Devin Harris, Tony Trapuzzano, Stephen Michael Alvarez, Tom Lee, Juliana , Jason Weinstein, Hoang Ton, Kris Siverhus, Alexander Walls, Annamaria Szilagyi, Morgan Williams, Abhijit Kiran Valluri, Mandeep Singh, Peter Owen, Sama aafghani, Vinicius Lhullier, Connor Wytko, 1) Surface Area to the Max! 3:21 2) Mouth to Esophagus 5:23 3) Stomach 6:38 4) Small Intestine 7:55 5) Large Intestine 9:44 References Campbell Biology, 9th ed. http://www.sciencedaily.com/releases/2007/10/071008102334.htm crash course, biology, anatomy, digestive system, animal, development, digestive tract, nervous system, vertebrate, micro-ecology, microorganism, human, omnivore, acid, enzyme, surface area, mouth, teeth, saliva, nutrient, intestine, salivary amylase, swallow, mastication, pharynx, esophagus, stomach, epiglottis, bolus, peristalsis, rugae, gastric juice, pepsin, chyme, duodenum, absorb, secrete, villi, gall bladder, liver, bile, emulsify, fatty acid, cecum, appendix, poop, anal, sphincter Support CrashCourse on Subbable: http://subbable.com/crashcourse Let’s Review Help me fill in the organs of the digestive system and watch what happens when we digest food. https://gizmos.explorelearning.com/index.cfm?method=cResource.dspView& ResourceID=1050 Fill in the worksheet to follow along! A Salivary glands B Tongue C Epiglottis D Esophagus E Liver F Stomach G Gallbladder H Duodenum I Pancreas J Small intestine K Large intestine L Cecum M Appendix N Rectum O Anus  An Overview- What’s the Role of the Digestive System? Role of the Digestive Systems Breakdown food for Energy and we can think of 4 major processes that occur: INGESTION- food enters through the mouth DIGESTION- breakdown food into smaller components (mechanical & chemical) ABSORPTION- nutrients are absorbed into the bloodstream so it can be delivered to all the cells in the body EGESTION- removal of waste products.  Mechanical Vs Chemical Digestion Mechanical Digestion Chemical digestion chemical breakdown of large, complex physical breakdown of food molecules into smaller, simpler chunks of food into smaller nutrient molecules that can be absorbed pieces by the blood. Where: mainly in the mouth Where: begins in the mouth and stomach but and stomach. occurs mainly in the small intestine.  Why do we break down food mechanically? POE: What happens to a sugar cube when ingested? How does this compare to granulated sugar? Predict: If sugar is in the form of a cube versus granulated, then _______________________________ would ________________. Rate of dissolution more for smaller granules | Solutions | Chemistry Here we study what happens when we try to dissolve different kinds of sugar in water. We start with three types of sugar - powdered, regular and large and add the same quantity of each kind of sugar to three glasses with equal amounts of water. Be careful not to stir the water after adding the sugar. We see that the powdered sugar dissolves first, followed by regular sugar and the large sugar is last to dissolve. This is because the rate of dissolution depends on the contact area between the substance and the solute. In a powder, the contact area is greater as more water comes into contact with the sugar, so it is the fastest to dissolve. Observe: Explain:  Why do we eat? Our body needs NUTRIENTS! Organic Compounds (made of C,H,O)- Inorganic Compounds - Can be Need to be broken down before being absorbed directly into the bloodstream absorbed into the bloodstream  Proteins: composed of a long chain of What’s AMINO ACIDS Inside Our - Found in meat, fish, legumes Food? Carbohydrates: composed of hydrogen, carbon and oxygen in a fixed ratio. Can be both simple and complex - Found in sugars, starches, breads, fruit MONOSACCHARDIES Fats/Lipids: can be both saturated (animal fats/butter) and unsaturated (oils). Questions! 1. Why do we need proteins in our diet? 1. Why do we need carbohydrates in our diet? 1. Why do we need lipids in our diet? Questions! 1. Why do we need proteins in our diet? building blocks for muscle 1. Why do we need carbohydrates in our diet? main source of energy 1. Why do we need lipids in our diet? Main component of cell membranes and long term energy storage, insulates and protects Enzymes: What are they? Proteins that act as biological catalyst. They regulates (increases) the rate of a chemical reaction (such as metabolism) within the body. Enzymes do not get used up, or become altered permanently! Therefore, they can be used over and over again! In this graph you can see the activation energy needed to start a reaction (red Enzymes decrease activation line) is much higher than the activation energy of a reaction (energy energy needed when an enzyme has been introduced to the reaction (blue) needed to START a reaction) Enzymes: The Active Site! Substrate: a molecule that is getting broken down or built up! Enzymes have an Active Site Area on an enzyme that has a special shape so that only a SPECIFIC SUBSTRATE will fit! Every substrate needs its HOW ENZYMES own enzyme in the body! (Lock and Key Hypothesis) WORK VIDEO! Example: Substrate: STARCH END PRODUCT: MALTOSE Enzyme: AMYLASE Breakdown of Nutrients Nutrients need to be broken down into smaller subunits in order to be absorbed in the digestive system! They do this using ENZYMES! The SUBUNITS (monomers) for each nutrient is: 1. Carbohydrates: Monosaccharides 2. Proteins: Amino Acids 3. Lipids: Glycerol and Fatty acids **there are a few types of lipids  CARBOHYDRATES Polysaccharides A long chain of monosaccharides (sugar units) Ex. Starch, Glycogen, Cellulose (Fibre) Amylase Disaccharides Two monosaccharides Ex. Maltose, sucrose and lactose Monosaccharides Lactase, Maltase, One sugar unit sucrase Ex. Glucose, fructose and galactose Chemical Digestion of Sugars Carbohydrates are the main source of energy for our cells!  PROTEINS Polypeptide A long sequence of amino acids Pepsin Dipeptide Two amino acids Amino acid Peptidase One protein unit Ex. Tryptophan, Histidine, etc. (20 AA’s in total that the human body needs)  LIPIDS Triglycerides Made of one glycerol backbone and 3 Fatty Acid Chains Bile is an emulsifier and Lipase breaks down lipids Ex. Fatty acids can be Saturated (no double bonds) or Unsaturated (contains double bonds) Glycerol 3 Fatty Acids **Other lipids include phospholipids, steroids and waxes  Digestion in the Mouth Mechanical digestion from teeth and tongue of all nutrients 1. Would you expect all animals to have the same teeth? Why? Or Why Not? 2. How is the structure of teeth related to their function? Now let's look at the path food takes! 1. Mouth 2. Pharynx 3. Esophagus 4. Stomach 5. Small intestine (duodenum, jejunum and ileum) 6. Large intestine (ascending, transverse and descending) 7. Rectum 8. Anus  Where it All Begins- The Mouth The Mouth is involved in both mechanical and chemical digestion. The main components involved in digestion in the mouth are: Teeth- tear and grind food into smaller pieces Tongue- mixes food, pushes it the back of the mouth Saliva- moistens food and contains salivary amylase that begins carbohydrate digestion. Epiglottis- Covers the trachea when swallowing to prevent food from entering the lungs  Digestion in the Mouth Chemical digestion: Salivary Amylase (enzyme) produced by salivary glands. Speeds of the reaction that breaks down starch (polysaccharide) into disaccharides Try this… Place a cracker on your tongue and let it sit there and soak up the saliva (contains amylase)... eventually the cracker should start to taste a bit more sweet due to the polysaccharides breaking down into simpler sugars! More on the Epiglottis After chewing, moist ball that is called a bolus that our tongue moves to the back of our throat Since our throat leads to both our lungs and our stomach we need a way to ensure food does not “go down the wrong tube” When swallowing, the epiglottis covers our trachea to direct the food to the ESOPHAGUS. What type of digestion happening with each type of nutrient in the mouth? Carbohydrate Chemical: Complex polysaccharides are broken down by amylase to disaccharides Mechanical breakdown Lipids Mechanical breakdown only Proteins Mechanical breakdown only  2) The Esophagus STRUCTURE: The esophagus is a long muscular tube that connects the mouth to the stomach. FUNCTION: The smooth muscles of the walls of the esophagus produce a rhythmic wave of contractions that push the food down into the stomach: PERISTALSIS Key Question: 1. How does the structure of the esophagus aid in its role? 2. If you were eating upside down, why would food still go to your stomach? 3. Smooth muscle contracts involuntary, what other type of muscle contracts involuntary? The Function of Peristalsis Peristaltic Wave in the Gastric Antrum Through the Esophagus The Function of Peristalsis This endoscopy videoclip shows the peristalsis in the lower part of the stomach, the antrum. Peristalis is a wavelike, constant, rhytmic movement caused by muscular contraction carrying food from the stomach through the pylorus into the duodenum, which is the first part of the small bowel. Research section: Gastroesophageal Reflux Disease (GERD): What are the physical manifestations of the disease? (symptoms, effects) What causes the disease? Explain what is shown in the diagram: Explain in detail how the disease disturbs the normal physiology(functioning) of the  3) The Stomach STRUCTURE: - An expandable “bag” - Rugae (folds) allow it to expand after eating - Sphincters that regulate food entering and leaving - Esophageal sphincter (controls food entering) - Pyloric sphincter (controls food leaving) - pH of approx. 2 - Produces mucus to protect from the acidic environment The Stomach FUNCTION: 1. Chemical digestion → Secretes gastric juices - HCl - Mucus → protection - Pepsinogen → pepsin - Breaks down proteins into dipeptides 1. Mechanical digestion - Churning to mix food Key Question: Why does the stomach require a low pH? Pepsin: Production, Activation & Regulation Pepsin is an enzyme responsible for breaking down proteins in the stomach. However, if the cells lining the stomach were to create Pepsin, then the Pepsin would breakdown the cell membrane (made of proteins) Therefore, the cells lining the stomach create a precursor known as: Pepsinogen. This is an inactive form of pepsin. Once Pepsinogen is secreted into the stomach it interacts with the HCl (low pH) and converts to the active form… Pepsin!  Mechanical & Chemical Digestion in the Stomach Key Questions: In order for the stomach to “churn,” what type of muscle should be in the lining? What is the purpose of the sphincters? Why does the stomach require a low pH? Pepsinogen is created by the stomach lining cells and once it it secreted into the stomach it turns into the enzyme pepsin that breaks down proteins into amino acids. Why does the stomach cells create pepsinogen first? How does gastric bypass surgery work? The Small Intestine - 3 main sections 1. Duodenum 2. Jejunum 3. Ileum - Primary site of absorption! - Breakdown of macromolecules through chemical digestion - Food is now called chyme How does chyme move through the intestines? Intestinal Peristalsis Anatomy  1- Duodenum STRUCTURE: - First shortest portion of SI - About 10 inches long in adults FUNCTION: - Primary site of chemical digestion - Cells release enzymes - Pancreas releases hormones, enzymes and sodium bicarbonate - Gallbladder releases bile (produced in the liver) → breaks down lipids What is the importance of sodium bicarbonate?  Pancreas Secretes pancreatic juices: - Enzymes → breakdown carbohydrate, protein and fat - Amylase - Lipase - Trypsin - sodium bicarbonate - Hormones - Glucagon - Insulin *Important for blood glucose regulation  Liver & Gallbladder LIVER: produces bile that helps emulsify fats GALLBLADDER: stores and concentrates bile. The bile duct releases bile into the duodenum. **INTESTINAL SECRETIONS (juices) (made in the duodenum) Bile - What Is Bile? In this video I discuss what bile is, and its main functions in fat digestion, red blood cell recycling, and cholesterol removal. Transcript What is bile? Bile is a digestive juice that is produced in the liver and stored in the gallbladder. Bile’s major function is that it is involved with fat digestion and absorption in the intestinal tract. So let’s take a very basic look at how this happens. Here we have Jayson, and he has just eaten a meal, and part of that meal contained some fat. And fat does not dissolve in water, so this means his body has to digest it in a different way than it would protein or carbohydrates. As fat moves through the digestive system, it mainly remains clumped together. When fat reaches the small intestine it basically is large fat droplets. And this is where bile does its job. - maltase, sucrase, lactase for carbohydrate, Bile is released into the small intestine, and it is able to mix with the large fat droplets. Bile contains bile salts, which allow it to emulsify the fat, or break it down into smaller droplets. Next, the enzyme pancreatic lipase comes in and breaks the fat into free fatty acids and monoglycerides. These free fatty acids and monoglycerides are now small enough to pass through the epithelial cell layer that covers the villi. Villi are tiny finger like projections that cover the interior of the small intestinal wall. Inside these villi are blood capillaries and lymph capillaries. Here fats are absorbed into the lymph capillary and transported to the liver by way of the lymphatic duct and circulatory system. So, as you can see, bile has a very important role in fat digestion and absorption. But bile does a couple of other things. It helps remove a substance called bilirubin, which is made when the body breaks down old blood cells. Bile also helps remove cholesterol, as some cholesterol is converted to bile acids and eliminated in bile in feces. peptidase for protein and lipase for fat digestion Duodenum: Enzymes & Chemical Digestion The duodenum is the primary site of chemical digestion. Below is a chart of enzymes: Pancreatic Hormones and Blood Sugar Regulation High Blood Sugar (After a Meal) Insulin is released by pancreas. 1) Stimulates glucose uptake by the cells 2) glucose --> glycogen formation in the liver. Low Blood Sugar (Fasting) Glucagon released by pancreas. 1) Stimulates breakdown of glycogen to glucose in the liver to be released into the bloodstream. VIDEO Questions 1. When will insulin be released into the bloodstream? Glucagon? 1. Which hormone will increase blood sugar levels? Which will decrease? 1. Do you think there are any other ways we can stimulate glucose uptake into cells? 1. What is the difference between someone who has diabetes vs. healthy in terms of uptake and hormone secretion? 4b) Small intestine: Jejunum & Ileum STRUCTURE: - jejunum (8ft), ileum (12ft) - finger like projections called villi → microvilli FUNCTION: - Main function is absorption of nutrients - villi have capillary bed so nutrients can be absorbed into the bloodstream and transported around the body Inside the Small Intestine 03-small intestines.mov Absorption of Food Research part: Celiacs Disease: What are the physical manifestations of the disease? (symptoms, effects) What causes the disease? Explain what is shown in the diagram: Explain in detail how the disease disturbs the normal physiology(functioning) of the system  Large Intestine STRUCTURE: - approx. 5 feet long - 3 main sections → ascending, transverse and descending FUNCTION: - main site of water and vitamin absorption -too little water absorption = diarrhea What would happen if the LI absorbed too much -not enough water in diet = water? Too little? constipation Swallowing a Pill Camera The Digestive System 'The Journey of the Digestive System' National Geographic own all rights to this video Summary... Key roles of all the organs involved in digestion. You Now Have A New Organ: Meet The Mesentery! Why did it take us so long to identify a new human organ? What does the mesentery do and how often are we "discovering" new organs? All Scientific Papers Should Be Free; Here's Why They're Not - https://youtu.be/69yF7ksLWC0 Sign Up For The Seeker Newsletter Here - http://bit.ly/1UO1PxI Read More: A Brand-New Human Organ Has Been Identified http://www.seeker.com/a-brand-new-human-organ-has-been-identified-2177481699.html "Scientists have known about the structure, which connects a person's small and large intestines to the abdominal wall and anchors them in place, according to the Mayo Clinic. However, until now, it was thought of as a number of distinct membranes by most scientists. Interestingly, in one of its earliest descriptions, none other than Leonardo da Vinci identified the membranes as a single structure, according to a recent review." Irish surgeon identifies emerging area of medical science https://www.eurekalert.org/pub_releases/2016-12/uol-isi121616.php "The mesentery, which connects the intestine to the abdomen, had for hundreds of years been considered a fragmented structure made up of multiple separate parts. However, research by Professor of Surgery at UL's Graduate Entry Medical School, J Calvin Coffey, describes the mesentery as one, continuous structure." Structural and functional features of central nervous system lymphatic vessels http://www.nature.com/nature/journal/v523/n7560/full/nature14432.html "One of the characteristics of the central nervous system is the lack of a classical lymphatic drainage system. Although it is now accepted that the central nervous system undergoes constant immune surveillance that takes place within the meningeal compartment, the mechanisms governing the entrance and exit of immune cells from the central nervous system remain poorly understood." ____________________ DNews is dedicated to satisfying your curiosity and to bringing you mind-bending stories perspectives you won't find anywhere else! New videos daily. Watch More DNews on Seeker http://www.seeker.com/show/dnews/ Subscribe now! http://www.youtube.com/subscription_center?add_user=dnewschannel Seeker on Twitter http://twitter.com/seeker Trace Dominguez on Twitter https://twitter.com/tracedominguez DNews on Facebook https://facebook.com/DiscoveryNews DNews on Google+ https://plus.google.com/u/0/+dnews Seeker http://www.seeker.com/ Sign Up For The Seeker Newsletter Here: http://bit.ly/1UO1PxI Written By: Trace Dominguez