The alimentary canal is the long tube of organs — including the esophagus, stomach, and intestines — that runs from the mouth to the anus.
An adult's digestive tract is about 30 feet about 9 meters long. Digestion begins in the mouth, well before food reaches the stomach. When we see, smell, taste, or even imagine a tasty meal, our salivary glands in front of the ear, under the tongue, and near the lower jaw begin making saliva spit. As the teeth tear and chop the food, spit moistens it for easy swallowing.
A digestive enzyme in saliva called amylase pronounced: AH-meh-lace starts to break down some of the carbohydrates starches and sugars in the food even before it leaves the mouth. Swallowing, done by muscle movements in the tongue and mouth, moves the food into the throat, or pharynx pronounced: FAIR-inks.
The pharynx is a passageway for food and air. A soft flap of tissue called the epiglottis pronounced: ep-ih-GLAH-tus closes over the windpipe when we swallow to prevent choking. From the throat, food travels down a muscular tube in the chest called the esophagus pronounced: ih-SAH-fuh-gus. Waves of muscle contractions called peristalsis pronounced: per-uh-STALL-sus force food down through the esophagus to the stomach. A person normally isn't aware of the movements of the esophagus, stomach, and intestine that take place as food passes through the digestive tract.
At the end of the esophagus, a muscular ring or valve called a sphincter pronounced: SFINK-ter allows food to enter the stomach and then squeezes shut to keep food or fluid from flowing back up into the esophagus.
During digestion, the body breaks down fat molecules into fatty acids and glycerol. Scientists classify vitamins by the fluid in which they dissolve. Water-soluble vitamins include all the B vitamins and vitamin C. Fat-soluble vitamins include vitamins A, D, E, and K. The body stores fat-soluble vitamins in the liver and fatty tissues, whereas the body does not easily store water-soluble vitamins and flushes out the extra in the urine.
Search Login. Inflammatory Bowel Disease Clinic. Salivary glands are cells producing saliva, which contains digestion enzymes. These enzymes are the first after chewing to meet food and start degrading them. Food molecules are then delivered through the throat to the esofagus, and they end up in the stomach afterwards through a series of contractions.
Watch this video to see how food moves through your GI tract. As food moves through your GI tract, your digestive organs break the food into smaller parts using:.
The digestive process starts in your mouth when you chew. Your salivary glands make saliva , a digestive juice, which moistens food so it moves more easily through your esophagus into your stomach. Saliva also has an enzyme that begins to break down starches in your food. After you swallow, peristalsis pushes the food down your esophagus into your stomach. Glands in your stomach lining make stomach acid and enzymes that break down food. Muscles of your stomach mix the food with these digestive juices.
Your pancreas makes a digestive juice that has enzymes that break down carbohydrates, fats, and proteins. The pancreas delivers the digestive juice to the small intestine through small tubes called ducts. Your liver makes a digestive juice called bile that helps digest fats and some vitamins. Bile ducts carry bile from your liver to your gallbladder for storage, or to the small intestine for use.
Your gallbladder stores bile between meals. When you eat, your gallbladder squeezes bile through the bile ducts into your small intestine. Your small intestine makes digestive juice, which mixes with bile and pancreatic juice to complete the breakdown of proteins, carbohydrates, and fats.
Bacteria in your small intestine make some of the enzymes you need to digest carbohydrates. Your small intestine moves water from your bloodstream into your GI tract to help break down food. Your small intestine also absorbs water with other nutrients. In your large intestine, more water moves from your GI tract into your bloodstream. Bacteria in your large intestine help break down remaining nutrients and make vitamin K. Waste products of digestion, including parts of food that are still too large, become stool.
The small intestine absorbs most of the nutrients in your food, and your circulatory system passes them on to other parts of your body to store or use. Special cells help absorbed nutrients cross the intestinal lining into your bloodstream.
Your blood carries simple sugars, amino acids, glycerol, and some vitamins and salts to the liver. Your liver stores, processes, and delivers nutrients to the rest of your body when needed.
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