Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Digestive System Characteristics 2 Part process to turn food into usable energy • 2 Types of Digestion • 1. Physical Digestion – breaks down larger pieces 2. Chemical Digestion – breaks down complex chemicals into simpler ones Physical Digestion • Teeth - most physical digestion takes place • Adult humans have 32 teeth. – 8 Incisors - teeth with a single cutting edge – 4 Canines - round teeth for puncturing. – 8 Premolars - teeth with several cutting edges for shredding. – 12 Molars - teeth with a flat surface for grinding. Parts of a tooth: • Enamel - the smooth, hard covering. • Dentin - the porous "bone" of the tooth. • Pulp - the cavity containing blood vessels and nerves. • Cementrum - binds the enamel to the dentin. Parts of a Tooth Main Organs • • • • • Mouth Esophagus Stomach Small intestine Large intestine ** The total length of the digestive system in an average adult is 8.5 meters (about 28 ft.) Digestive System Large Intestine Organs that help • Liver • Gallbladder • Pancreas Mouth • The teeth physically break down food into small particles, saliva begins to mix with the food. • Saliva is a mixture of water, mucus, and the digestive enzyme called salivary amylase. Esophagus • Muscular tube connects the mouth with the stomach. • Food passes through this tube by rhythmic smooth muscle contractions and relaxations called peristalsis. Stomach Stomach • holds 2-3 pints • produces about the same amount of gastric juices every 24 hours. • Both mechanical and chemical digestion occur in this J-shaped elastic bag Stomach continued • cardiac sphincter is closed, food cannot reenter the esophagus. • pyloric sphincter, located at the lower end of the stomach, opens to release food a little at a time. • Food usually remains in the stomach for 3-4 hours. Stomach Continued • The outer walls of the stomach are composed of three layers of muscle – circular layer, – longitudinal layer, and – diagonal layer. – Together, these muscles twist and turn the stomach Small intestine • chemical digestion is completed and nutrients are absorbed into the blood stream • The lining is highly folded to form microscopic fingerlike projections called villi Villi Large Intestine • Also known as your colon • 1.5 liters of water in the material that enters the large intestine (9L in small intestine) • Minerals, vitamins, and the rest of the water are absorbed into the blood stream from the large intestine Liver • 30% of the blood pumped through the heart in one minute passes through the liver to be cleaned • The liver is the largest gland in the body, weighing 21/2 to 31/2 pounds. • The liver produces bile to be stored in the gallbladder. Liver Disease - Cirrhosis • Caused by alcohol abuse (average of 3 drinks/day over a long period of time) • Also caused by chronic hepatitis C (from sharing needles in drug use) Gallbladder • Food passing into the small intestine causes the gallbladder to secrete bile • Bile helps liquefy fats to ease their digestion. Pancreas • Pancreatic fluid is secreted into the small intestine to break down food • Insulin is released to break down sugar Spleen • Most misunderstood organ • meshwork of tiny blood vessels • it filters the blood and removes abnormal blood cells • it makes disease-fighting components Fun Fact To pass through the entire digestive system takes 18 – 20 hours! Quiz Yourself! 1. What type of muscle lines the Esophagus? 2. What are 3 things that make up saliva? 3. There is an opening on the top and bottom of your stomach what are they called? 4. What are 4 parts of a tooth? 5. Muscle contractions down the esophagus are called? 13. What does the Pancreas Make? 14. What are two types of digestion and where do they take place in the body?