Digestive System • Your body needs fuel to operate • Just like a car, train, or airplane needs fuel to operate • The body system that converts fuel to usable energy is your Digestive System • This system also helps control the elimination of used-up fuel in the form of wastes. • The process of changing food into material the body can use is called digestion • Involves both mechanical & chemical processes
Mechanical Process of digestion • Chewing and mashing food into smaller pieces • Chemical Process of digestion • Breaking food down into particles with digestive enzymes • Enzymes are proteins that effect the many body processes. • Digestive Enzymes speed up the breakdown of food.
The Mouth and Teeth • Digestion starts in the mouth • Teeth tear and grind food • into small pieces(Mechanical) • Taste buds on your tongue sense flavor & mouth produces saliva (chemical) • Saliva is a fluid made by the salivary glands that moisten and softens food, making it easier to swallow. • Saliva also contains enzymes that help break down food
Stomach & Small Intestine • Food passes from mouth to esophagus • The Esophagus is a muscular tube that pushes food down into the stomach in a process called peristalsis • Peristalsis is a series of involuntary waves that carry food particles along. • Stomach • Food continues to be broken down • Glands in stomach wall release gastric juices, a blend of hydrochloric acid and enzymes. (chemical) • Hydrochloric acid is strong enough to break down metal • Stomach has protective lining that protects this powerful acid from digesting itself
Stomach and Small Intestine (cont.) • Stomach serves as a temporary storage area for food. • Some food remains in stomach for as long as 4 hours • Most digestion occurs in Small Intestine • Small intestine is a coiled, tube like organ that is about 20 feet long. • Here nutrients separate from the bulk of the food • Nutrients then enter the bloodstream and travel to the body cells where they are used for growth, energy, and repair.
Organs That Aid Digestion • Assisted by 3 Important Organs • Food does NOT pass through these organs • Liver • 2nd largest organ in body • Produces Bile, a substance that helps break down fats • Gallbladder • Stores Bile and releases it into small intestine as needed • Pancreas • Makes additional digestive enzymes that are released directly into small intestine. • Produces Insulin to help glucose to be absorbed into the body cells • Diabetes is a disorder of the pancreas. • Pancreas produces too little or no insulin
Excretory (Urinary)System • Once all nutrients are extracted from food, all that remains is liquid and solid waste. • Body wastes consist of food materials that can NOT be digested • Excretory System is your body’s waste removal system • Process of removing wastes from your body is known as excretion http://www.youtube.com/watch?v=XF_lF3J4ZKs
The Process of Excretion • Food particles that cannot be digested move from the small intestine to the large intestine, or colon • Liquid waste is either absorbed in colon, released through pores in skin (perspiration), or sent to the kidneys • Kidneys are organs that filter water and dissolved wastes from the blood and help maintain proper levels of water and salts in the body • Waste materials filtered out by the kidneys leave the body as urine • Solid waste products that remain are called feces and leave the body through the anus
Parts of the Excretory System • Kidneys- Main organs, remove liquid waste (urea) from the blood • Ureters- The tubes that carries urine from the kidney to the bladder • Bladder- Stores liquid waste before it leaves the body • Urethra- The tube that releases liquid waste (urine) from the body
Problems of Digestive & Excretory System • Have you ever overeaten or ate too fast? • This discomfort is called Indigestion • Indigestion is body’s way of telling you to eat slowly and control amount you eat • Diarrhea (watery feces) • Food might be contaminated with bacteria • Heartburn – burning sensation in center of chest or throat. Has nothing to do with heart • Result of stomach acids flowing backward into esophagus
Taking Care of Your Digestive and Excretory Systems • Eat a variety of healthy foods. Choose low-fat & high fiber foods from all food groups. FRUITS & VEGGY’S • Don’t rush meals • Chew food thoroughly. Don’t wash large pieces down • Drink plenty of water!! Water is good for digestive system, drink 6 to 8 ounce glasses a day. • Wash hands regularly. Before preparing or eating food wash hands with soap & water. Always wash after using the restroom.