Digestive System

1. Digestive System

2. The Digestive System • Also known as the gastrointestinal system • responsible for the physical and chemical breakdown of food so that it can be taken into the bloodstream and used by body cells and tissues. • consists of the alimentary canal, and accessory organs.

3. Alimentary Canal- long, muscular tube that begins at the mouth and includes: • mouth (oral cavity) • pharynx • Esophagus • Stomach • small intestine • large intestine • anus

4. Accessory Organs- • 1. salivary glands • 2. Tongue • 3. Teeth • 4. Liver • 5. Gallbladder • 6. pancreas.

5. Mouth (Oral Cavity) • Buccal Cavity • receives food as it enters the body • While food is in the mouth: it is tasted, broken down physically by the teeth, lubricated and partially digested by saliva, and swallowed. • Teeth: are special structures in the mouth that physically break down food by chewing and grinding= mastication. • Tongue: muscular organ that contains special receptors called taste buds= allow a person to taste sweet, salty, sour, and bitter sensations. • Also aids in chewing and swallowing food.

6. Hard Palate- bony structure that forms the roof of the mouth and separates the mouth from the nasal cavities. • Soft Palate- Behind the hard palate, it separates the mouth from the nasopharynx . • Uvula- cone-shaped muscular structure, hangs from the middle of the soft palate. • prevents food from entering the nasopharynx during swallowing • Salivary glands- • the parotid, sublingual, and submandibular • produce a liquid called saliva. • Saliva-lubricates the mouth during speech and chewing, also moistens food so that it can be swallowed easily. • contain an enzyme called salivary amylase- which begins the chemical breakdown of carbohydrates or starches, into sugars that can be taken into the body.

7. After the food is chewed and mixed with saliva, it is called a bolus. • When the bolus is swallowed, it enters the pharynx (throat). • Pharynx- tube that carries both air and food. • air to the trachea, food to the esophagus • When a bolus is being swallowed, muscle action causes the epiglottis to close over the larynx , preventing the bolus from entering the respiratory tract and causing it to enter the esophagus. • Esophagus- muscular tube dorsal (behind) the trachea. • receives the bolus from the pharynx and carries the bolus to the stomach. • relies on a wavelike, involuntary movement of its muscles called peristalsis= to move the food in a forward direction.

8. Stomach- enlarged part of alimentary canal • receives the food from the esophagus • mucous membrane lining of the stomach has folds, calledrugae. • The rugae disappear when the stomach fills with food and expands. • Food remains in the stomach for 2-4 hours • During this time, food is converted into a semi-fluid material , called chyme, by gastric juices produced by glands in the stomach. • Gastric Juices contain hydrochloric acid and enzymes. • Hydrochloric acid kills bacteria, facilitates iron absorption, and activates the enzyme pepsin. • Enzymes include: lipase, which starts the chemical breakdown of fats, and pepsin, which starts protein digestion.

9. Small Intestine- when the food in the form of chyme, leaves the stomach, it enters the small intestine. • coiled section of the alimentary canal , approximately 20 feet in length and 1 inch in diameter. • Divided into three sections: • duodenum- first 9-10 inches of the small intestine • Bile from the gallbladder and liver and pancreatic juice from the pancreas enter this section through ducts, or tubes. • Jejunum- approximately 8 feet in length and forms the middle section of the small intestine. • Ileum- final 12 feet of the small intestine and it connects with the large intestine at the cecum. • While food is in the small intestine, the process of digestion is completed, and the products of digestion are absorbed into the bloodstream for use by the body cells.

10. Large Intestine- final section of the alimentary canal. • approximately 5 feet in length and 2 inches in diameter • Functions: absorption of water and any remaining nutrients, storage of indigestible materials before they are eliminated from the body, synthesis and formation of some b-complex vitamins and vitamin K by bacteria present in the intestine, transportation of waste products out of the alimentary canal. • Divided into a series of connected sections: • Cecum • Colon • Ascending colon • Transverse colon • Descending colon • Sigmoid colon- s-shaped colon that connects with the rectum • Rectum- storage area for indigestible and wastes. • has a narrow canal, called the anal canal, which opens at a hole, called the anus. • Anus- Fecal material, or stool, the final waste product of the digestive process, is expelled through this opening

11. Accessory Organs • Liver- largest gland in the body and is an accessory organ to the digestive system. • located under the diaphragm and in the upper right quadrant of the abdomen. • secretes bile, which is used to emulsify fats in the digestive tract. • Bile also makes fats water soluble, which is neccessary for absorption. • stores sugar in the form of glycogen, which is converted to glucose and released into the bloodstream when additional blood sugar is needed. • stores iron and certain vitamins • detoxifies (renders less harmful) substances such as alcohol and pesticides, and destroys bacteria that have been taken into the blood from the intestine.

12. Accessory Organs • Gallbladder- small, muscular sac located under the liver and attached to it by connective tissue. • stores and concentrates bile, which it receives from the liver. • When the bile is needed to emulsify fats in the digestive tract, the gallbladder contracts and pushes bile through the cystic duct in to the common bile duct, which drains into the duodenum. • Pancreas- glandular organ located behind the stomach. • produces pancreatic juices, which contain enzymes to digest food. • these juices enter the duodenum through the pancreatic duct • also produces insulin which is secreted into the bloodstream. • Insulin- regulates the metabolism, or burning, of carbohydrates to convert glucose (blood sugar) to energy.

15. Diseases and Abnormal Conditions

16. Appendicitis • Acute inflammation of the appendix, usually resulting from an obstruction and infection • Symptoms: generalized abdominal pain that later localizes at the lower right quadrant, nausea, vomiting, mild fever, and elevated white blood cell count. • If the appendix ruptures, the infectious material will spill into the peritoneal cavity and cause peritonitis, a serious condition. • Treatment: appendectomy, surgical removal of the appendix

17. Hemorrhoids • Painful dilated or varicose veins of the rectum/anus. • Cause: straining to defecate, constipation, pressure during pregnancy, insufficient fluid intake, laxative abuse, and prolonged sitting or standing • Symptoms: pain, itching, and bleeding • Treatment: high-fiber diet, increased fluid intake, stool softeners, sitz bath, sometimes a hemorrhoidectomy (surgical removal of the hemorrhoids).

18. Hernia • rupture, occurs when an internal organ pushed through a weakened area or natural opening in a body wall. • hiatal hernia- stomach protrudes through the diaphragm and into the chest cavity through the opening for the esophagus • Symptoms- heartburn, stomach distention, chest pain, and difficulty swallowing • Treatment: bland diet, small frequent meals, staying upright after eating, and surgical repair.

19. Ulcer • open sore on the lining of the digestive tract • Peptic ulcers include gastric (stomach) ulcers and duodenal ulcers • Cause: bacterium, helicobacter pylori (H. pylori), buries into the stomach membranes, allowing stomach acids and digestive juices to create an ulcer. • Symptoms- burning pain, indigestion, hematemesis (bloody vomitus), melena (dark, tarry stool) • Treatment: antacids, bland diet, decreased stress, and avoidance of irritants such as alcohol, fried foods, tobacco, and caffeine. • If the bacteria is present treatment with antibiotics or pepto-bismol , usually cures the condition. • Surgery sometimes needs to be done to remove the affected area.

20. Study for your Quiz! -Next Class- Appendectomy Hemorrhoidectomy Gastric Hematemesis Melena

22. Chapter 5 Nutrition and Your Health

23. The Importance of Good Nutrition Good nutrition enhances your quality of life and helps you prevent disease. It provides you with the calories and nutrients your body needs for maximum energy and wellness. NUTRITION:THE PROCESS BY WHICH THE BODY TAKES IN AND USES FOOD. NUTRIENTS:SUBSTANCES IN FOODS THAT YOUR BODY NEEDS TO GROW, TO REPAIR, AND TO PROVIDE ENERGY. CALORIES:UNITS OF HEAT THAT MEASURE THE ENERGY USED BY THE BODY AND ENERGY SUPPLIED TO THE BODY BY FOODS. The Teen Years

24. What Influences Your Food Choices? • 1.Hunger and Appetite: • Hunger:Natural need to eat and not starve. • Appetite:A desire to eat. • 2.Emotions: • Stress, Anger, Happy, Sad, Boredom, etc, • 3.Environment: • Family and Friends • 4.CulturalandEthnicBackground: • Race, Religion, Heritage • 5.ConvenienceandCost: • Where you live, On the go lifestyle, Family income • 6.Advertising: • Health messages, Influence your looks

25. Nutrients • 6GROUPSOFNUTRIENTS: • Carbohydrates • Proteins • Fats • Vitamins • Minerals • Water

26. Carbohydrates • Simple carbohydrates: are sugars. Examples include: • glucose • fructose • lactose. • Carbohydrates:are the starches and sugars present in food. • They are classified as either simple or complex. • Complexcarbohydratesare starches. Examples include: • whole grains • seeds • legumes • - Fiber is an indigestible complex carbohydrate that helps move waste through the digestive system. • Body’s preferred source of energy. • Body converts all carbohydrates to glucose, a simple sugar. • Glucose is not used right away and it is stored as glycogen. • Too many carbohydrates will cause the body to store the excess as fat.

27. Proteins are classified into two groups: complete and incomplete. Complete proteins contain amounts of all nine essential amino acids. SOURCES INCLUDE: *Fish, meat, poultry, eggs, milk, cheese, yogurt, and many soybean products. Incomplete proteins lack one or more essential amino acids. SOURCES INCLUDE: *Beans, peas, nuts, and whole grains. Proteins have many functions: - Help make new cells. -Help make and repair tissues. - Help make enzymes, hormones, and antibodies. - Provide energy. Proteins Proteinsare nutrients that help build and maintain body cells and tissues.

28. Fats are a type of lipid, a fatty substance that do not dissolve in water. The building blocks of fats are called fatty acids Fatty Acids are classified as two types Saturated: Animal fats and tropical oils High intake is associated with an increased risk of heart disease Unsaturated: Vegetable fats Associated with a reduced risk of heart disease Fatty acids that the body needs, but is unable to make are called essential fatty acids Transport vitamins A, D, E, and K Sources of linoleic acid- essential fatty acid that is needed for growth and healthy skin High intake of saturated fats is linked to increased cholesterol production Excess cholesterol can lead to an increased risk of heart disease Fats

29. Water-soluble vitamins dissolve in water and pass easily into the blood during digestion. The body does not store these so they need to be replenished regularly. Includes vitamins C, B1 ,B2, Niacin, B6, Folic acid, and B12. Fat-soluble vitamins are absorbed, stored, and transported in fat. Your body stores these vitamins in your fatty tissue, liver, and kidneys. Excess buildup can be toxic.These include vitamins A, D, E, and K. Vitamins and Minerals • Vitaminsare compounds that help regulate many vital body processes that include: • Digestion 2. Absorption 3. Metabolism 4. Circulation • Vitamins are classified into two groups: Minerals are substances that the body cannot manufacture but are needed for forming healthy bones and teeth and regulating many vital body processes. Importantmineralsinclude: -Calcium -Phosphorus –Magnesium -Iron

30. Water Water helps to maintain many bodily functions. • Lubricates your joints and mucous membranes. - Enables you to swallow and digest foods. • Absorb other nutrients, and eliminate wastes. - Perspiration helps maintain normal body temperature. • Water makes up around 65% of the body. • It’s important to drink at least 8 cups of water a day to maintain health.

31. The Food Guide Pyramid Healthful Eating Are You Eating A Balanced Diet?

32. Nutrition and Product Labeling • Product labeling advertise a food’s nutritious value. • Some common used terms are light, less, free, more, rich, rich in, lean, or excellent source of. • Many food products have open dates on their label. • Examples are expiration date, freshness date, pack date, and sell-by date.

33. Food Sensitivity and Foodborne Illness • 1. Food Allergy- a condition in which the body’s immune system reacts to substances in some foods. • Allergies to peanuts, tree nuts, eggs, wheat, soy, fish, and shellfish. • A simple blood test can can indicate whether a person is allergic to a specific food. • These reactions may include rash, hives, or itchiness of the skin; vomiting, diarrhea or abdominal pain; or itchy eyes and sneezing. • 2. Food Intolerance - a negative reaction to a food or part of a food caused by a metabolic problem. • The inability to digest parts of certain foods or food components. • May be associated with certain foods such as milk or wheat, or even with some food additives. • Common symptoms include nausea, vomiting, diarrhea, and fever.

34. 3. Foodborne Illness – A term that means a person has food poisoning. • To prevent foodborne illness you should clean, separate, cook and chill food when handling it. • A foodborne illness can result from eating foods contaminated with pathogens or poisonous chemicals. • The symptoms from the most common types of food poisoning generally start within 2 to 6 hours of eating the food responsible. That time may be longer (even a number of days) or shorter, depending on the toxin or organism responsible for the food poisoning. The possible symptoms include: nausea/vomiting, abdominal cramps, diarrhea, weakness, fever and headache. • Even though food poisoning is relatively rare in the United States, it affects between 60 and 80 million people worldwide each year and results in approximately 6 to 8 million deaths.