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Intestines (Anatomy): Picture, Function, Location, Conditions

Last Updated: Apr 08, 2023

Intestines Image

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The intestines, both the small and the large ones, are connected channels that go from the stomach all the way down to the anus. The intestines are responsible for the majority of the body's absorption of fluids and nutrients.

The intestine plays a vital role in maintaining the health of the body by supporting digestion, absorption, and elimination, and by regulating the immune system and electrolyte balance. It is home to a large population of beneficial bacteria, known as the gut microbiota, which play a role in supporting the immune system and helping to prevent the growth of harmful bacteria.

Intestine Anatomy

  • The small intestine, also known as the small bowel, is approximately 20 feet long, and its diameter is approximately one inch. Its primary function is to absorb the majority of the water and nutrients that we take in from the outside world in the form of food and drink.
  • The duodenum, jejunum, and ileum are the three sections of the small intestine, which are separated by the tissue that borders them. The jejunum is responsible for the majority of the absorption that occurs.
  • The large intestine, also known as the large bowel, is approximately 5 feet long and has a diameter of approximately 3 inches. It does this by absorbing water from waste, both digested and undigested.
  • Despite the fact that absorption is quite low at this stage in comparison to the absorption that occurs in the small intestine. The remainder is processed into faeces, which travels into the rectum and remains there as long as a signal for the need to defecate is not received.

Intestine Functions

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The main functions of the intestine include:-

  • Digestion: The intestine is responsible for breaking down food into smaller molecules that can be absorbed into the bloodstream. This process is aided by enzymes produced by the pancreas and small intestine, as well as by bacteria in the large intestine.
  • Absorption: The intestine absorbs the nutrients from the digested food and transports them to the liver, where they are processed and stored.
  • Elimination: The intestine also eliminates waste products from the body, including undigested food, bacteria, and toxins.
  • Maintaining electrolyte balance: The intestine helps to maintain the balance of electrolytes, such as sodium, potassium, and chloride, in the body.
  • Regulating the immune system: The intestine is home to a large population of beneficial bacteria, known as the gut microbiota. These bacteria play a role in supporting the immune system and helping to prevent the growth of harmful bacteria.

Overall, the intestine plays a vital role in maintaining the health of the body by supporting digestion, absorption, and elimination, and by regulating the immune system and electrolyte balance.

Intestine Diseases

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  • Stomach flu (enteritis): The term 'stomach flu' refers to inflammation of the small intestine that may be caused by infections with viruses, bacteria, or other parasites. Inflammation of the small intestine can lead to diarrhoea and vomiting.
  • Small intestine cancer: A very unusual instance of cancer of the small intestine has been discovered. Cancer is the leading cause of mortality throughout the globe, and this holds true in every nation. There are many subtypes of cancer that affect the small intestine.
  • Celiac disease: Gluten 'sensitivity' refers to a condition in which the small intestine is unable to absorb nutrients as it should. Protein is the primary component of gluten, which cannot be adequately digested by the body. Pain in the abdomen and a decreased appetite are two of its symptoms.
  • Carcinoid tumour: A growth in the small intestine that may be either benign or cancerous. It is possible to have symptoms such as diarrhoea and flushing of the skin.
  • Intestinal obstruction: The term 'intestinal obstruction' refers to a condition that occurs when a section of the small intestine, the large intestine, or both become obstructed, twisted, or simply cease to function normally. Patients report experiencing symptoms such as abdominal distension, discomfort, constipation, and vomiting.
  • Colitis: Colitis is a term that refers to inflammation of the colon. Inflammatory bowel disease and infections are the two primary causes of this condition.
  • Diverticulitis: Diverticulitis is caused when the diverticula in the digestive tract becomes inflamed or infected. In most cases, patients report experiencing symptoms such as stomach discomfort and constipation.
  • Colon bleeding (haemorrhage): It can be caused by a number of different problems. If you are bleeding quickly, you can see it in your poop. If you are bleeding slowly, you might not see it.
  • Crohn's disease: Crohn's disease is an inflammatory disease of the intestines and colon. Symptoms like stomach pain and diarrhoea are common, as is a headache.
  • Diarrhea: It is a common name for stools that are loose, watery, and happen more than three times a day. Most cases of diarrhoea are caused by mild infections of the colon or small intestine.
  • Shigellosis: This is caused by the bacteria Shigella, which can get into food and infect the intestine. There are signs like fever, stomach pain, and diarrhoea, which may be accompanied by blood.
  • Traveller's diarrhoea: This happens because water or food in developing countries is often contaminated with many different kinds of bacteria. Loose stools are common, and nausea and fever may also be present.
  • Small Bowel Obstruction: When the normal flow of the small bowel is blocked, stool or gas can't leave the body. As the blood supply is cut off, ischemia or necrosis can happen. On the other hand, it can look like only a small amount of gas can pass.
  • Paralytic ileus: It happens when peristalsis slows down or stops completely. This causes constipation and an inability to eat by mouth, which leads to paralytic ileus.
  • Hernias: hernias are when a part of the bowel sticks out through a weak spot in the abdominal fascia. It can either be able to be broken down into smaller parts or not. In reducible, it can be forced back into the abdominal wall, but this is not seen in irreducibles.
  • Irritable Bowel Syndrome (IBS): IBS is a disorder of the GI tract that causes chronic abdominal pain and changes in the way you go to the bathroom. These include gut visceral hypersensitivity, motility disorder, abnormal immune system function, and a changed microbiome.
  • Cyclic Vomiting Syndrome: This is when you throw up often but feel fine in between. Most of the time, it happens with migraines. For the first week, the person throws up every morning, but after a few weeks or months, there are times when they are healthy again.
  • Colon polyps: colon polyps are growths that happen inside the colon. They are a type of tumour. After many years, these tumours often lead to colon cancer.
  • Colon cancer: Most people in the world get colon cancer . Even though it can be avoided with regular checkups.
  • Constipation: It occurs when you don't go to the bathroom as often or as easily as you should. Because bowel movements are so erratic, the poop stays in the colon of the large intestine.
  • Rectal prolapse: rectal prolapse occurs when a part or all of the wall of the rectum comes out of place, sometimes coming out of the anus, when you strain to go to the bathroom.
  • Intussusception: It mostly happens to kids. Like a telescope, the small intestine can fold into itself. If you don't treat it right away, it can become life-threatening.
  • Diverticulosis: In this there is formation of a false outpouching of the mucosal layers of the colon. This usually happens where the vasa recta enters the colon muscularis . It is most often found in the area of the sigmoid colon. This condition is more likely to happen if you have symptoms like increased intraluminal pressure, which is constipation.
  • Sigmoid volvulus: It is a condition in which the sigmoid colon twists around its mesentery, blocking the intestine. High risk people have a long sigmoid and a narrow mesentery. There are signs like growing stomach pain, nausea, bloating, and trouble going to the bathroom.
  • Celiac disease5: These are a condition in which submucosal veins in the anal mucosa get bigger.
  • Celiac disease7: This happens when the lining of the anal canal tears away from the line where the teeth meet. Most of the time, it's in the back midline and usually comes with skin tags.
  • Celiac disease9: pilonidal cyst is a disorder of the soft tissue in the upper gluteal cleft. There are debris plugs and hair follicles in the cyst, which could lead to an infection.
  • Whipple disease: This happens when the small intestine grows too much. This causes macrophages to build up, pus to form, chronic diarrhoea, abdominal pain, arthralgias, and often weight loss.
  • Tropical Sprue: People who have lived in an endemic area for at least one month and have had diarrhoea can get a disease called tropical sprue, which has no clear cause.
  • SIBO(Small Intestinal Bacterial): This overgrowth is when there are too many colonic bacteria in the small intestine.
  • Toxic megacolon: This is a condition in which the colon is dilated without being blocked and there is systemic toxicity.

Intestine Tests

  • Virtual colonoscopy: A procedure that utilises an X-ray machine in conjunction with a computer in order to produce images of the lining of the colon. In the event that issues are discovered, a conventional colonoscopy is typically required.
  • Faecal occult blood testing: A test for the presence of blood in the faeces. If blood is discovered in the stool, a colonoscopy may be required in order to locate the cause of the problem and treat it.
  • Sigmoidoscopy: An examination to determine whether or not there is blood in the faeces. If blood is discovered in the stool, a colonoscopy may be necessary in order to locate the cause of the problem and treat it.
  • Colon biopsy: In the course of a colonoscopy, a sample of colon tissue may be extracted in order to be analysed further. Colon biopsies can assist in the diagnosis of colon cancer, as well as infections and inflammations.
  • Anoscopy: An anoscopy is a diagnostic procedure that includes peering into the lining of your anus and rectum with the assistance of a tiny tube that is referred to as an anoscope. An anoscopy is also known as an endoscopy. It is a simple medical test that may aid your doctor in identifying whether or not there is an issue with your digestive tract. If there is, then this test will show it.
  • Abdominal CT: A diagnostic imaging examination known as a computed tomography (CT) scan of the abdomen and pelvis can be performed. During an abdominal CT scan, a specialised X-ray machine is used to capture images of the patient's organs, including the liver, spleen, kidneys, bladder, stomach, intestines, pancreas, and adrenal glands.
  • CTA with oral + IV contrast: In CT angiography, a CT scanner is utilised to obtain high-resolution images of various regions of the body's blood arteries as well as their surrounding tissues.
  • Flex Sigmoidoscopy: In flexible sigmoidoscopy, a skilled medical expert makes use of a flexible, narrow tube that has a light and tiny camera attached to one end.
  • FIT (fecal immunochemical test): The faecal immunochemical test, often known as the FIT, is a test that can detect colon cancer. This examination looks for traces of blood in the stool, as this can be an early indicator of malignancy. The test, which is performed once a year, is a screening for colorectal cancer.
  • FOBT: A faecal occult blood test, often known as a FOBT, examines a sample of your stool (poop) to determine whether or not it contains blood. Blood that is occult is blood that cannot be seen with the unaided human eye.
  • Hydrogen breath test: This is a test to determine whether an individual is lactose, fructose, or sucrose intolerant. Glucose is a type of sugar that, if it is present in the small intestine, will be broken down by bacteria, which will result in the production of hydrogen or methane gas.


Intestine Treatments

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  • Enema: A term for pushing liquid into the colon through the anus. Enemas can deliver medicines to treat constipation or other colon conditions.
  • Colonoscopy: Certain disorders that affect the colon can be treated by a physician using instruments that are inserted through an
  • Endoscope. A colonoscopy may be used to diagnose and treat bleeding, polyps, or cancer.
  • Polypectomy: Polypectomy is the term used to describe the removal of a colon polyp by means of colonoscopy.
  • Colon surgery: It is possible to remove all or part of the colon by either open or laparoscopic surgery (colectomy). In cases of serious bleeding, malignancy, or ulcerative colitis, this procedure may be performed.
  • Perineal anoplasty or colostomy: Perineal anoplasty is a surgical treatment that can be used to treat imperforate anus, a condition in which the anus is either missing, blocked, or positioned in the improper area. Imperforate anus can be treated when the anus is absent, obstructed, or located in the incorrect location.
  • TEF ligation, with esophageal anastomosis: In neonates who are not responding to artificial breathing, TEF ligation may be an emergent procedure. On the other hand, EA/TEF repair is an urgent operation to reduce the risk of aspiration.
  • Hepatoportoenterostomy (Kasai procedure): In order to facilitate bile drainage, a surgical procedure known as a hepatoportoenterostomy or Kasai portoenterostomy may be carried out on newborns who have been diagnosed with Type IVb choledochal cyst with biliary atresia.
  • Duodenoduodenostomy: An anastomosis (or a surgical connection) between two duodena is what is meant by the term 'duodenoduodenostomy.'. This surgical procedure is used to treat duodenal atresia.
  • Gastrografin enema: An x-ray examination of the big bowel is referred to as a gastrografin/barium enema (colon). The lining of the large bowel is coated with a liquid contrast agent that is injected into the colon.
  • Colonoscopic decompression: Colonoscopic decompression is a beneficial way for eliminating air from the colon and, as a result, lowering the risk of subsequent colonic perforation, which is the rupture of the colonic wall.
  • Laparoscopic appendectomy: When appendix get inflamed and causes symptoms of appendicitis then removal of appendix is done which is called appendectomy and if it is done through laparoscopic procedure then it is called as laparoscopic appendectomy
  • IV fluid resuscitation: The basic objective of fluid resuscitation is to preserve organ perfusion (hemodynamics), as well as substrate concentrations (oxygen, electrolytes, among others).
  • Nasogastric tube insertion: When a nasogastric tube is inserted, access is granted to the patient's stomach and the contents of the stomach. This allows you to drain the contents of the stomach as well as decompress the stomach.
  • Balloon angioplasty /stent: The treatment known as balloon angioplasty is performed to open arteries that have become constricted or obstructed. After this, a device that has a miniature balloon attached to its tip is passed into your arteries until it reaches the capillaries that have been constricted.
  • Mesenteric embolectomy or bypass: It is possible to recover from mesenteric infarction caused by an embolus to a superior mesenteric artery if circulation is restored through embolectomy.

Intestine Medicines

  • Stool softeners: Medications available both over-the-counter and by prescription can help relieve constipation and soften the stool.
  • Laxatives: Medications can treat constipation in a variety of ways, including activating the muscles in the gut and increasing the amount of water that is absorbed by the body. One of the examples is lubiprostone, which is a chloride channel activator that boosts the amount of fluid that is secreted by the intestinal tract.
  • Histamine (H2) blockers: The histamine enhances secretions of the stomach acid; blocking histamine decreases secretions of acid production and GERD symptoms etc. Some of the examples include Cimetidine and Famotidine.
  • Proton Pump Inhibitors: These are responsible for the direct inhibition of the acid pumps in the stomach. Some of the examples include Omeprazole, Lansoprazole, Esomeprazole, and
  • Dexlansoprazole: When proton pump inhibitors are taken for a longer period then some side effects are evolved.
  • Anti-Diarrheal Agent: Loperamide is also used for chronic or recurrent diarrhoea caused by In the case of dumping syndrome, ulcerative colitis or Crohn's disease recurrent diarrhoea evolves for which it is given.
  • Prebiotics: In the therapeutic treatment, they are used to boost the activity of beneficial bacteria in the gut, which allows for a more stable pH level in the gut to be maintained as required.
  • Probiotics: They are beneficial to the ecosystem of the gut and provide beneficial microorganisms such as Bifidobacterium and Lactobacillus.
  • Antibiotics: Prescribed in synergistic effect with other treatments which may or may not be caused because of infection of h. pylori . During treatment, the antibiotics are given to the stomach in an effort to heal the damage caused by the infection.
  • Antiparasitic drugs: For the treatment of infection spread because of parasitic aetiology the medicines which are regularly used can be albendazole, mebendazole and praziquantel . In the treatment of bacterial infections, some examples include azithromycin, ciprofloxacin, and tetracycline.
  • Antiviral Medications: A number of antiviral drugs, such as entecavir, tenofovir , lamivudine ,adefovir , and telbivudine, can aid in the fight against the virus and lessen its ability to harm your intestines.
  • Chemotherapeutic Drugs: Chemotherapy and radiation are effective treatments for intestines cancer, despite the disease's untreatable nature. In extreme cases, the intestines may be removed surgically or replaced with a donor organ.
  • Statins: This class of drugs is known as lipid-lowering medicines, and it has other beneficial properties for slowing the development of acute or chronic intestinal disease, such as lowering oxidative stress and inflammation. Rosuvastatin, atorvastatin, etc ,are all instances of statins.

Frequently Asked Questions (FAQs)

What causes intestines problem?

The main causes of intestine problems are stress, a low-fibre diet, lack of exercise, and excess consumption of dairy products.

How do you know if you have intestine issues?

Swollen Belly, cramps, gas, abdominal pain, bleeding, pain in the belly and diarrhoea give you signs that you are suffering from intestinal issues.

How do you clean your intestines?

Maintaining hydration and drinking lots of water are also excellent ways to control digestion. It has also been demonstrated that drinking lukewarm water is beneficial for digestion. Try consuming a lot of meals that are high in water content as well. Fruits and vegetables including watermelons, tomatoes, lettuce, and celery are included in this.

What can damage the intestines?

Decreased blood flow, eating a low-fibre diet, food poisoning, gas, bowel diseases, and lack of exercise can damage your intestine.

What foods can clean intestines?

Apple cider vinegar, apple, garlic, lemon, water, avocados, broccoli, spinach, juices, herbal teas, and watermelons are some of the foods that help to clean the intestines.

How long does it take to heal intestines?

The gut may require up to six months to completely heal.

Are intestines part of the digestive system?

Yes, the intestines are part of the digestive system.

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Written ByDrx Hina FirdousPhD (Pharmacology) Pursuing, M.Pharma (Pharmacology), B.Pharma - Certificate in Nutrition and Child CarePharmacology
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Reviewed ByDr. Bhupindera Jaswant SinghMD - Consultant PhysicianGeneral Physician

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