Transcript Digestion
Digestion includes both mechanical and chemical processes. • Digestion- the mechanical and chemical breakdown of foods for use by the body’s cells. • Absorption- the passage of digested food from the digestive tract into the cardiovascular system. • Elimination- the expulsion of undigested food or body wastes. •The mechanical portion involves chewing, mashing, and breaking food into smaller pieces. •The chemical process involves digestive juices that change food into simpler substances. The Nervous and cardiovascular systems also play a major role in the digestion process. • The nervous system triggers the digestive process • Nutrients are carried through the body by the cardiovascular system. The digestive process begins in the mouth which consists of the: • teeth – break down the food into smaller pieces. • The salivary glands – produce the first digestive juices in the digestive process. • The tongue – forms chewed food into a size and shape that can be swallowed. The Esophagus: The Stomach: •A Muscular tube about 10 inches long, that connects the pharynx and the stomach. •A hollow saclike organ enclosed in a muscular wall. •Peristalsis: a series of involuntary muscle contractions that moves food through the digestive tract.) The Pancreas, Liver, and Gallbladder •The pancreas creates enzyme that break down the carbohydrates, fats, and proteins in food. •The liver produces another digestive juice called bile (yellow-green bitter fluid important in the breakdown and absorption of fats.) •Between meals the bile is stored in the gallbladder. •The stomach contains many gastric juices •Holds food for further digestion. As food is digested in the stomach, it is converted into chyme (a creamy fluid mixture of food and gastric juices.) The Small Intestine: • It is 20 to 23 feet in length and 1 inch in diameter. • Consists of three parts: • Contains millions of fingerlike projections called villi. The Large Intestine: • It is 2.5 inches in diameter and 5 to 6 feet in length. • Absorbs water, vitamins, and salts. • Eliminates wastes. Taking care of your digestive system begins with the choices you make about the food that you eat. The following health behaviors will keep your digestive system healthy: •Follow a well balanced diet that includes a variety of foods. •Wash your hands before preparing a meal and before eating. •Eat slowly and chew food thoroughly. •Drink at least eight 8-ounce glasses of water each day. •Avoid using food as a way of dealing with your emotions. The following are problems of the digestive system: •Indigestion •Heartburn •Gas •Constipation •Nausea •diarrhea Problems Include: •Gallstones •Crohn’s Disease •Appendicitis •Colon Cancer •Gastritis •Colitis •Lactose Intolerance •Hemorrhoids •Peptic Ulcer •Tooth Decay •Cirrhosis DIGESTIVE SYSTEM Endocrine System Where are the Glands? Pituitary Pituitary The pituitary gland produces a growth hormone which controls growth and homeostasis. Parathyroid Parathyroid The parathyroid gland produces parathormone which controls calcium levels in the body. Adrenals The adrenal glands produce Adrenals Adrenals adrenaline in response to physical and emotional stress. Thyroid Thyroid The thyroid gland produces thyroxin to regulate metabolism. Pancreas Pancreas The pancreas produces insulin which controls sugar levels in the blood. Testes (in males) The testes produce Testes testosterone used in sperm production and the development of male traits. Ovaries (in Females) The ovaries Ovaries produce estrogen used in egg production and the development of female traits.