Chapter 7-2 Digestion and Absorption PDF

FSHN 285 Chapter Seven How the Body Uses Food: Digestion and Absorption You are not the same person that you were a month ago. Although your body may look and feel the same, the substances that make up the organs...

FSHN 285 Chapter Seven How the Body Uses Food: Digestion and Absorption You are not the same person that you were a month ago. Although your body may look and feel the same, the substances that make up the organs and tissues of your body are constantly changing. Each day, about 5% of our body weight is replaced by new tissue. For example, taste cells are replaced every 7 days, cells lining the intestinal tract every 1 to 3 days, all the cells of the skin are replaced about every month ,and the cells lining the intestinal tract are replaced every 1 to 3 days. All the cells of the skin are replaced every month and red blood cells turn over every 120 days. Nutrients are the components in food that serve as raw materials for maintenance. It’s through the processes of digestion and absorption that nutrients are released and made available for cells in the body to use. The Internal Travels of Food: An Overview: Some have described the digestive tract as the body’s food processor. The digestive tract is a 25 to 30 foot long muscular tube that extends from the mouth to the anus and includes organs such as the pancreas and liver that secrete digestive juice. Much of the work of digestion is accomplished by enzyme systems such as the salivary glands, stomach, and pancreas. Enzymes are complex protein substances that initiate or speed up chemical reactions designed to break down food. A remarkable feature of enzymes is that they are not changed by the chemical reactions they affect. This makes them reusable. Carbohydrates, proteins and fat each have their own set of digestive enzymes. All together, over a 100 different enzymes participate in the digestion of carbohydrates. Parts of the GI tract (page 85): Salivary glands. Functions: They produce enzymes that to help break down starch and fats  Tongue. Functions: Mastication (chewing) and mixing of food with saliva Esophagus. Functions: Transfer the food to the stomach Stomach. Functions: Secretes enzyme that breaks down proteins and fats. Also mixing and liquifying the food. Liver. Functions: Produces bile that aids fat digestion. Gallbladder. Functions: Stores and secretes bile that aids in fat digestion Bile duct. Functions: Conduct bile to the small intestine Pancreas. Functions: Secretes enzymes that break down carbohydrates, proteins and fats Pancreatic Duct. Functions: Conducts pancreatic juice into the small intestine Small intestine. Functions: Secretes enzymes that break down the majority of the carbohydrates, proteins and fats. Large intestine. Functions: The site of absorption of water and intestinal bacteria Rectum. Functions: Stores our waste products for releasement Anus. Functions: Holds rectum closed and opens for releasement of waste Let’s look at some of the digestive enzymes. Identify what foods they work on and where they are produced (page 86): Carbohydrate digestion: Amylase: Produce in the salivary glands and pancreas. They break down starch into smaller chains of glucose molecules Sucrase: Produce in the small intestine. They separate disaccharides sucrose into monosaccharides glucose and fructose. Lactase: Produced in the small intestine. Split the disaccharides lactose into glucose and lactose. Maltase: Produce in the small intestine. Separates maltose into molecules of glucose. Fat digestion: Lipase: Produce in salivary glands and pancreas. Breaks down fats into fragments of fatty acids and glycerol. Protein Digestion: Pepsin: Produce in the stomach. Separates proteins into shorter chains of amino acids Trypsin: Produce in the pancreas. Splits a short chain of amino acids into molecules containing 1, 2, or 3 amino acids. Review the table at the bottom of page 86 and answer these questions: 1. Which acid works to uncoil protein strands? Stomach 2. What part of the body carries away undigested fiber? Large intestine 3. What body fluid readies fat for the action of lipase? Saliva 4. Where does starch digestion begin? Mouth True False After food is chewed, it is swallowed and passes through the esophagus to the liver. True False Foods tend to stay in the stomach for 2-3 hours. True False Liquids pass through the stomach in about 20 minutes. True False If laid flat, the surface area of the small intestine would be about the size of a football field. Absorption: Digestion is complete when carbohydrates, fats, and proteins are reduced to substances that can be absorbed, and when vitamins and minerals are released from food. In order to be absorbed: Carbohydrates are broken down to: Monosaccharides and Disaccharides Fat into: Fatty acid and glycerol molecule Protein into: Amino acid Those end products of digestion- glucose, fatty acids, glycerol, and amino acids-are absorbed in the stomach and the large intestine; though nutrient absorption occurs primarily in the small intestine. When consumed with meals, about 30% of alcohol is absorbed in the stomach; the remainder is absorbed in the small intestine. Water, sodium, and chloride are mostly absorbed by the large intestine. The Lymphatic and Circulatory Systems: The end products of digestion are taken up by the lymphatic system and the circulatory system for eventual distribution to all cells in the body. Lymph vessels and blood vessels infiltrate the villi that line the inside of the intestines and transport absorbed nutrients toward the major branches of the lymphatic and circulatory systems. The broken-down products of fat digestion are largely absorbed into lymph vessels, whereas proteins and carbohydrates breakdown products enter the blood vessels. The nutrient rich contents of the lymphatic system are transferred to the bloodstream at a site near the heart where vessels from both systems merge into one vessel. From there, the lymph and blood mixture is sent to the heart and subsequently throughout the body by way of the circulatory system. Nutrients delivered by the circulatory system reach every organ and tissue in the body, supplying cells with the nutrients obtained from food. Beyond absorption: Cells can use nutrients directly for energy, to repair or build body structures, or to regulate body processes. For example, glucose can be used as is for energy formation or converted to glycogen and stored for later use. Fatty acids, an end product of fat digestion, can be incorporated into cell membranes, used in the production of certain hormones or used as fuel for energy formation. Vitamins and minerals freed from food by digestion can be used by cells to regulate enzyme activity or tissue maintenance. The body has a limited storage capacity for some vitamins and minerals. Consequently, excessive amounts of certain vitamins and minerals such as vitamin C, thiamine, and sodium are largely excreted in the urine. Taste Sensor Regulation: List the 5 basic taste sensations: Sweet, Bitter, Salty, Savory, and Sour Gut Microbiota: - Consume and break down fiber and other undigested food leftovers  - Producing a short chain of fatty acids from the end product of fiber digestion, then are used to serve a source of energy - Minimizing the entry of toxins and potential inflammatory compounds into our bloodstream - Helps fight backing infection and the prevention of inflammation - Producing biotin, vitamin B12, and Vitamin K The human body is home to trillions of microbes, predominantly bacteria, introduced into the body through food, air, and contact with the external environment. The collection of the microorganisms in and on humans is referred to as the human Microbiome. True False Our gut contains around 100 trillion microbial organisms. True False Humans start life with a sterile gut. True False Our diet can influence our gut microbial. True False Gut microbial help fight infection. True False Gut microbials can be disrupted by antibiotics. Digestive Disorders: Digestive disorders are accounting for over 48 million medical visits and approximately 10% of hospitalizations in the U.S. every year. Constipation: Constipated is defined as fewer than 3 bowel movements per week. What is typically the cause of constipation? Dietary factors How many grams of dietary fiber are recommended per day? 25 to 30 grams What are the 5 myths related to constipation: 1. Leads to body absorbing toxins and poisonous substances 2. Colon cleansing or detoxing the body prevent constipation 3. Need to bowel movement every single day 4. Constipation can be lessen by consuming more fiber 5. To treat constipation you need to drink a lot of water Ulcers: Where do ulcers primarily occur? In the lining of stomach and the duodenum of the small intestine What is H.pylori? Is the ingested of foods and other substances that are contaminated with saliva, vomit, feces from a person bacteria kept in the stomach Gastrointestinal Reflux: What are the symptoms of heartburn? Painful, burning feeling in the chest or throat. What occurs in the body that people experience GER? The value of the stomach weakens allowing acid contents of the stomach to go back up into the esophagus. What are 4 interventions to reduce GER? 1. Not lying down for 1 to 2 horse after eating 2. Elevation of head when sleep 3. Quit Smoking 4. Medication Irritable Bowel Syndrome: What is the incidence of irritable bowel syndrome in the U.S.? 12% Who is more likely to experience IBS? 1. Women 2. Under the age 50 years old 3. Lifestyle and Medical Conditions 4. A extreme stress or traumatic events early in your life 5. Food intolerances and sensitivities 6. Mental Health Conditions Is irritable bowel syndrome life threatening? No List some lifestyle factors that help control irritable bowel syndrome: 1. With a healthy dietary pattern 2. Avoidance of large meals 3. Stress management 4. Medication 5. Adding soluble fibers 6. A specific probtiotics 7. Avoid food that seem to promote your IBS Diarrhea: How many times per year does the average adult American experience diarrhea? 4 times Is diarrhea life threatening? Yes How can we reduce our risk of developing diarrhea? Through food and water sanitation programs immunizations and adequate diet. What is the recommended treatment after someone has diarrhea? Eat solid foods such as, yogurt, milk, chicken, potatoes, vegetables, dried beans, rice, and cereals. It’s best to not consume sugary fluids. Flatulence: List 4 causes of flatulence: 1. Eating or drinking too fast 2. Bacterial Production in large intestine 3. Fructose 4. Sorbitals