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Digestive System. What is digestion and where does it start?. The Digestive System. Digestion Absorption Elimination. Digestion. Mechanical break down of foods Teeth-break down food into small pieces Masticaiton—process of chewing Chemical break down of foods
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Digestive System What is digestion and where does it start?
The Digestive System • Digestion • Absorption • Elimination
Digestion • Mechanical break down of foods • Teeth-break down food into small pieces • Masticaiton—process of chewing • Chemical break down of foods • Saliva-produced by the salivary glands; the first juices used in the process; break down starches and sugars in foods; lubricates food making it easier to swallow. • Both for use by the cells of the body
Digestion • Chemical break down of foods • Saliva-produced by the salivary glands; the first juices used in the process; break down starches and sugars in foods; lubricates food making it easier to swallow. • Bile • Stomach acids • Enzymes • Pepsin
Digestion • Tongue • Forms chewed food into a size and shape that can be easily swallowed • Esophagus • 10” muscular tube that connects the pharynx with the stomach
Digestion • Peristalsis • A series of involuntary muscle contractions that move food through the digestive tract • Esophagus • Stomach • intestines
Digestion • Stomach • Hollow, sac-like organ surrounded by muscles which allow for expansion during ingestion. • 3 Jobs • Mix foods with gastric juices • Store swallowed food and liquid • Move food into small intestine
stomach • Mix food with juices: • Secretions from the stomach lining that contain HYDROCHLORIC ACID,& PEPSIN, an enzyme that breaks down proteins • HCL—kills bacteria in food and creates an acidic environment for the pepsin to do its job • Mucus in the lining of the stomach protects the stomach from being digested in its own juices
stomach • Chyme • The creamy fluid mixture of food and gastric juices formed in the stomach. • YUCK!!! But it is what it is!!! :~)
Indirect Digestive Organs • Pancreas • Liver • Gall Bladder
pancreas • Organ that produces enzymes that break down the carbohydrates, fats, and proteins we consume. • Organ that is essential in insulin (blood sugar regulator) control.—Diabetes I and II.
liver • Organ that produces bile • Yellow-green fluid that helps break down and absorb fats • Jaundice—when the liver is not functioning properly the skin and eyes can become yellow from an excess of bile in the system.
gall bladder • Connects liver to digestive tract as a gateway for the bile • You can live without, but fatty foods will affect the body more than a body with a gall bladder. • Can become filled with painful gall stones
Absorption • Passage of digested food from the digestive tract into the cardiovascular system through capillaries in the villi of the intestines
absorption • Small Intestine • 20-23’ long • 1” diameter • Finishes digestion and begins absorption in the villi—finger-like projections in intestines • Large Intestine (colon) • 5-6’ long • 2.5” diameter • Finishes absorption and begins elimination
Elimination • Expulsion of undigested food or body wastes • Begins with large intestine—eliminate feces • Skin excretes some wastes through the pores—sweating • Lungs expel CO2 and other gas wastes • Liquids are filtered to the urinary tract for expulsion