Human Body Systems – Functions, locations, anatomy, definition, picture

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DIGESTIVE SYSTEM-BIRD-MAMMAL-REPTILE-COMPARISON
This major organ acts as a storage tank for food so that the body has time to digest large meals properly. This process, called digestion , allows your body to get the nutrients and energy it needs from the food you eat. Pharynx is marked off. Your contribution may be further edited by our staff, and its publication is subject to our final approval. It is located just inferior to the stomach and wraps around the superior and lateral border of the small intestine. Chewing does aid digestion, however, by reducing food to small particles and mixing it with the saliva secreted by the salivary glands.

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Movie: Digestive System

Do not eat or drink anything for at least 4 hours before the test. Inform your doctor if you regularly take anticoagulants or nonsteroidal anti-inflammatory drugs such as aspirin, ibuprofen, or naproxen. These medications must be discontinued for some time before the test to reduce the risk of bleeding complications. You will begin the test sitting up on a table.

A local anesthetic such as lidocaine is sprayed onto the back of your throat to suppress the gag reflex as the capsule and tube are inserted. The doctor inserts the lubricated capsule and tube into your throat and then asks you to flex your neck and swallow to aid in the advancement of the tube down through your esophagus. You will not be able to speak when the tube is inserted, but your breathing will not be affected.

Next, you will lie on your right side as the doctor advances the capsule and tube into your stomach, through the pylorus the opening of the stomach into the small intestine , and finally into the small intestine. Continuous x-ray imaging, or fluoroscopy, is used to guide the progress and positioning of the device. To obtain the biopsy sample, a syringe is attached to the outer end of the tube and suction is applied.

The suction draws a small piece of tissue into the capsule and then closes off the capsule, which cuts off the tissue from the intestinal lining. The tube is slowly withdrawn, and the tissue sample is sent to a laboratory for analysis.

The procedure lasts 45 to 60 minutes. When performed by a skilled professional, small bowel biopsy is typically safe and well-tolerated. Rare but serious complications of this procedure include bleeding, blood infection, and perforation of the bowel which requires surgical repair. You may leave the testing facility promptly after the test is completed. Do not eat or drink anything until your gag reflex returns, usually in a few hours.

Touching the back of the throat with a tongue depressor tests for this reflex. You may have black, tarry stools due to bleeding for a short period of time. Contact your doctor immediately if you develop a fever or abdominal pain.

Biopsy specimens are sent to a pathology laboratory and examined under a microscope for changes that indicate a bacterial or parasitic infection or another abnormality. This test usually results in a definitive diagnosis. The liver has many functions, but two of its main functions within the digestive system are to make and secrete bile, and to cleanse and purify the blood coming from the small intestine containing the nutrients just absorbed.

The gallbladder is a pear-shaped reservoir that sits just under the liver and stores bile. Bile is made in the liver then if it needs to be stored travels to the gallbladder through a channel called the cystic duct. During a meal, the gallbladder contracts, sending bile to the small intestine. Once the nutrients have been absorbed and the leftover liquid has passed through the small intestine, what is left of the food you ate is handed over to the large intestine, or colon.

The colon is a 5- to 6-foot-long muscular tube that connects the cecum the first part of the large intestine to the rectum the last part of the large intestine.

It is made up of the cecum, the ascending right colon, the transverse across colon, the descending left colon, and the sigmoid colon so-called for its "S" shape; the Greek letter for S is called the sigma , which connects to the rectum.

Stool, or waste left over from the digestive process, is passed through the colon by means of peristalsis contractions , first in a liquid state and ultimately in solid form as the water is removed from the stool.

A stool is stored in the sigmoid colon until a "mass movement" empties it into the rectum once or twice a day. It normally takes about 36 hours for stool to get through the colon. The stool itself is mostly food debris and bacteria. These bacteria perform several useful functions, such as synthesizing various vitamins , processing waste products and food particles, and protecting against harmful bacteria.

When the descending colon becomes full of stool, or feces, it empties its contents into the rectum to begin the process of elimination. The rectum Latin for "straight" is an 8-inch chamber that connects the colon to the anus. It is the rectum's job to receive stool from the colon, to let you know there is stool to be evacuated, and to hold the stool until evacuation happens.

When anything gas or stool comes into the rectum, sensors send a message to the brain. The brain then decides if the rectal contents can be released or not. If they can, the sphincters muscles relax and the rectum contracts, expelling its contents. If the contents cannot be expelled, the sphincters contract and the rectum accommodates, so that the sensation temporarily goes away.

The anus is the last part of the digestive tract. It consists of the pelvic floor muscles and the two anal sphincters internal and external muscles. The lining of the upper anus is specialized to detect rectal contents. It lets us know whether the contents are liquid, gas, or solid. The pelvic floor muscle creates an angle between the rectum and the anus that stops stool from coming out when it is not supposed to.

The anal sphincters provide fine control of stool. The internal sphincter keeps us from going to the bathroom when we are asleep, or otherwise unaware of the presence of stool.

When we get an urge to go to the bathroom, we rely on our external sphincter to keep the stool in until we can get to the toilet. Continued Three organs play a pivotal role in helping the stomach and small intestine digest food:

Fun facts about the digestive system