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DIGESTION. Definitions. Digestive system : a group of organs and tissues in the body that transform complex molecules to simple ones so nutrients can be absorbed Organ : a structure composed of several tissues working together to perform a function
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Definitions • Digestive system: a group of organs and tissues in the body that transform complex molecules to simple ones so nutrients can be absorbed • Organ: a structure composed of several tissues working together to perform a function • Gland: an organ or group of cells which secretes enzymes or hormones • Enzyme: chemical that causes changes in the body
Definitions continued • Peristalsis: muscle contractions that push food through a tube • Bolus: chewed food • Chyme: nutrients in semi-liquid form • Uvula: component that stops food from entering nasal cavity • Epiglottis: component that stops food from entering the trachea • Absorption: nutrients pass from intestines to blood by diffusion
Passage way • Mouth • Pharynx • Esophagus • Stomach • Small intestine • Large intestine • Rectum • Anus
Physical/Mechanical Breakdown • Food DOES NOT change its molecular makeup, just its shape and size, looks different • Mouth- chewing and swallowing • Esophagus- peristalsis • Stomach- churning, grinding and peristalsis • Small intestine- peristalsis and churning • Large intestine- peristalsis and churning
Chemical Breakdown • Food changes its molecular makeup, looks and is different • See handout
Absorption • Through folds called villi by diffusion • Small intestine – amino acids, glucose, glycerol and fatty acids • Large intestine – vitamins, minerals and water