Physiology, Large Intestine


Article Author:
Laura Azzouz


Article Editor:
Sandeep Sharma


Editors In Chief:
Kranthi Sitammagari
Mayank Singhal


Managing Editors:
Avais Raja
Orawan Chaigasame
Khalid Alsayouri
Kyle Blair
Radia Jamil
Erin Hughes
Patrick Le
Anoosh Zafar Gondal
Saad Nazir
William Gossman
Hassam Zulfiqar
Navid Mahabadi
Hussain Sajjad
Steve Bhimji
Muhammad Hashmi
John Shell
Matthew Varacallo
Heba Mahdy
Ahmad Malik
Abbey Smiley
Sarosh Vaqar
Mark Pellegrini
James Hughes
Beenish Sohail
Hajira Basit
Phillip Hynes
Sandeep Sekhon


Updated:
4/16/2019 10:33:38 PM

Introduction

The large intestine, also known as the colon, is part of the digestive tract. The digestive tract includes the mouth, esophagus, stomach, small intestine, large intestine, and rectum. The large intestine is approximately 5 feet long, making up one-fifth of the length of the gastrointestinal (GI) tract. The large intestine is responsible for processing indigestible food material (chyme) after most nutrients are absorbed in the small intestine. The large intestine is composed of 4 parts. It includes the cecum and ascending colon, transverse colon, descending colon, and sigmoid colon. The large intestine performs an essential role by absorbing water, vitamins, and electrolytes from waste material.[1][2][3][4]

Function

The large intestine has 3 primary functions: absorbing water and electrolytes, producing and absorbing vitamins, and forming and propelling feces toward the rectum for elimination. By the time indigestible materials have reached the colon, most nutrients and up to 90% of the water has been absorbed by the small intestine. The role of the ascending colon is to absorb the remaining water and other key nutrients from the indigestible material, solidifying it to form stool. The descending colon stores feces that will eventually be emptied into the rectum. The sigmoid colon contracts to increase the pressure inside the colon, causing the stool to move into the rectum. The rectum holds the feces awaiting elimination by defecation.

Mechanism

Motility

The intestinal wall is made up of multiple layers. The 4 layers of the large intestine from the lumen outward are the mucosa, submucosa, muscular layer, and serosa. The muscular layer is made up of 2 layers of smooth muscle, the inner, circular layer, and the outer, longitudinal layer. These layers contribute to the motility of the large intestine. There are 2 types of motility present in the colon, haustral contraction and mass movement. Haustra are saccules in the colon that give it its segmented appearance. Haustral contraction is activated by the presence of chyme and serves to move food slowly to the next haustra, along with mixing the chyme to help with water absorption. Mass movements are stronger and serve to move the chyme to the rectum quickly.

Absorption of Water and Electrolytes

Absorption of water occurs by osmosis. Water diffuses in response to an osmotic gradient established by the absorption of electrolytes. Sodium is actively absorbed in the colon by sodium channels. Potassium is either absorbed or secreted depending on the concentration in the lumen. The electrochemical gradient created by the active absorption of sodium allows for this. Chloride ions are exchanged for bicarbonate ions across an electrochemical gradient.

Production/Absorption of Vitamins

The colon also plays a role in providing required vitamins through an environment that is conducive for bacterial cultivation. The colon houses trillions of bacteria that protect our gut and produce vitamins. The bacteria in the colon produce substantial amounts of vitamins by fermentation. Vitamin K and B vitamins, including biotin, are produced by the colonic bacteria. These vitamins are then absorbed into the blood. When dietary intake of these vitamins is low in an individual, the colon plays a significant role in minimizing vitamin disparity.

Pathophysiology

Disorders of Large Intestinal Motility[5][6]

Irritable Bowel Syndrome

Irritable bowel syndrome is thought to be due to psychological factors influencing the motility of the large intestine via the extrinsic autonomic nervous system. During times of stress, segmentation contractions may be increased or decreased, resulting in constipation or diarrhea.

Hirschsprung Disease: Megacolon[7]

Hirschsprung disease is a disorder at birth that occurs when nerve cells are absent (Auerbach’s Plexus) in the muscles of the colon. This affects motility in the colon, making it difficult to pass stool.

Diverticulosis/Diverticulitis[8]

Diverticulosis is a disorder in which pockets develop in the colonic mucosa due to the weakness of the muscle layers in the colon wall. This usually occurs over time from chronic attrition of the aging process. Diverticulitis can develop if these pockets get infected or inflamed, causing abdominal pain and change in bowel movements. Diverticular disease is very common, especially in older adults.

Colitis[9]

Inflammatory Bowel Disease (Inflammatory)

Inflammatory bowel disease includes either Crohn's disease or ulcerative colitis. Both cause inflammation and scarring within the digestive tract, disrupting the normal function. The cause of inflammatory bowel disease is not known but is likely due to an abnormal response of the immune system. Ulcerative colitis is confined to the large intestine, whereas Crohn's disease can occur anywhere in the GI tract, from mouth to anus.

Ischemic

Ischemic colitis is more common in the elderly and occurs when there is decreased blood flow to the colon. Decreased blood flow can cause inflammation or injury to the colon. Some causes of ischemic colitis are atherosclerosis of arteries, low blood pressure, blood clots, and bowel obstruction.

Infectious 

Infectious colitis can occur from many different viruses, bacteria, or parasites. Infectious colitis most commonly occurs due to ingestion of contaminated food or water, introducing the infectious organism into the colon. The most common causes are Escherichia coli, Campylobacter, Shigella, and Salmonella. These infectious organisms invade the colon, cause inflammation, and affect the normal function, causing abdominal pain and diarrhea. Clostridium difficile is another organism that can cause colitis in association with antibiotic use. C. difficile is part of healthy, normal flora in the colon but can cause problems if it overgrows. Antibiotic use can destroy other susceptible normal flora in the colon, allowing overgrowth and invasion of C. difficile.

Clinical Significance

Disturbance or dysfunction of the large intestine’s normal physiology can result in poor quality of life and significant medical issues. Pathology of the large intestine is common. One out of every 10 Americans over the age of 40 have diverticular disease, and around 3 million people in the United States have inflammatory bowel disease.  It is important to incorporate a healthy diet and lifestyle to maintain a properly functioning colon. Eating a diet high in fiber and drinking plenty of water allows food to easily move through the colon, keeping the colon relatively clean, which can decrease the risk of diverticular disease. It is also important to maintain healthy colonic flora. Maintaining healthy colonic flora will decrease the risk of abdominal bloating, gas, diarrhea, constipation, and infectious colitis.[10]


Interested in Participating?

We are looking for contributors to author, edit, and peer review our vast library of review articles and multiple choice questions. In as little as 2-3 hours you can make a significant contribution to your specialty. In return for a small amount of your time, you will receive free access to all content and you will be published as an author or editor in eBooks, apps, online CME/CE activities, and an online Learning Management System for students, teachers, and program directors that allows access to review materials in over 500 specialties.

Improve Content - Become an Author or Editor

This is an academic project designed to provide inexpensive peer-reviewed Apps, eBooks, and very soon an online CME/CE system to help students identify weaknesses and improve knowledge. We would like you to consider being an author or editor. Please click here to learn more. Thank you for you for your interest, the StatPearls Publishing Editorial Team.

Physiology, Large Intestine - Questions

Take a quiz of the questions on this article.

Take Quiz
Which of the following organs absorbs water, salts, and electrolytes?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following organs is retroperitoneal?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which part of the gastrointestinal tract has the main function of reabsorption of water and electrolytes?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 25-year-old man presents with intermittent abdominal pain and bloody diarrhea for the past few months. He describes the pain as crampy and states that heavy meals make the pain and diarrhea worse. Physical exam reveals tender nodules on the lower extremity and tenderness to palpation of the right lower abdomen. What would biopsy of the colon show in this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following is not a function of the large intestine?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
What disease is caused by an absence of Auerbach plexus in the colon?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
What is a potential complication of chronic disruption of the normal flora in the large intestine?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
A 45-year-old woman presents with diffuse, watery diarrhea and abdominal cramps for the past three days. The patient denies having blood or mucus in her stool. The patient takes omeprazole daily and received oral antibiotics for pneumonia two and a half weeks ago. She has a temperature of 100.4 F. What test could be performed to confirm the diagnosis in this patient?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
Which of the following would not contribute to maintaining the healthy function of the colon?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
What characteristic of the colon wall assists with the movement of chyme?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up
How does water absorption in the large intestine occur?



Click Your Answer Below


Would you like to access teaching points and more information on this topic?

Improve Content - Become an Author or Editor and get free access to the entire database, free eBooks, as well as free CME/CE as it becomes available. If interested, please click on "Sign Up" to register.

Purchase- Want immediate access to questions, answers, and teaching points? They can be purchased above at Apps and eBooks.


Sign Up

Physiology, Large Intestine - References

References

Sulaiman S,Marciani L, MRI of the Colon in the Pharmaceutical Field: The Future before us. Pharmaceutics. 2019 Mar 27;     [PubMed]
Precup G,Vodnar DC, Gut Prevotella as a possible biomarker of diet and its eubiotic versus dysbiotic roles-A comprehensive literature review. The British journal of nutrition. 2019 Mar 29;     [PubMed]
Wang YHW,Wiseman J, Anatomy, Abdomen and Pelvis, Rectum 2019 Jan;     [PubMed]
Ogobuiro I,Tuma F, Physiology, Gastrointestinal 2019 Jan;     [PubMed]
Farooqi N,Tuma F, Intestinal Fistula 2019 Jan;     [PubMed]
Ishihara S,Kawashima K,Fukuba N,Tada Y,Kotani S,Mishima Y,Oshima N,Kinoshita Y, Irritable Bowel Syndrome-Like Symptoms in Ulcerative Colitis Patients in Clinical Remission: Association with Residual Colonic Inflammation. Digestion. 2019;     [PubMed]
Heuckeroth RO, Hirschsprung's disease, Down syndrome, and missing heritability: too much collagen slows migration. The Journal of clinical investigation. 2015 Dec;     [PubMed]
Lambrichts DPV,Birindelli A,Tonini V,Cirocchi R,Cervellera M,Lange JF,Bemelman WA,Di Saverio S, The Multidisciplinary Management of Acute Complicated Diverticulitis. Inflammatory intestinal diseases. 2018 Dec;     [PubMed]
Click B,Regueiro M, The Inflammatory Bowel Disease Medical Home: From Patients to Populations. Inflammatory bowel diseases. 2019 Apr 1;     [PubMed]
Czepiel J,Dróżdż M,Pituch H,Kuijper EJ,Perucki W,Mielimonka A,Goldman S,Wultańska D,Garlicki A,Biesiada G, Clostridium difficile infection: review. European journal of clinical microbiology     [PubMed]

Disclaimer

The intent of StatPearls is to provide practice questions and explanations to assist you in identifying and resolving knowledge deficits. These questions and explanations are not intended to be a source of the knowledge base of all of medicine, nor is it intended to be a board or certification review of PA-Hospital Medicine. The authors or editors do not warrant the information is complete or accurate. The reader is encouraged to verify each answer and explanation in several references. All drug indications and dosages should be verified before administration.

StatPearls offers the most comprehensive database of free multiple-choice questions with explanations and short review chapters ever developed. This system helps physicians, medical students, dentists, nurses, pharmacists, and allied health professionals identify education deficits and learn new concepts. StatPearls is not a board or certification review system for PA-Hospital Medicine, it is a learning system that you can use to help improve your knowledge base of medicine for life-long learning. StatPearls will help you identify your weaknesses so that when you are ready to study for a board or certification exam in PA-Hospital Medicine, you will already be prepared.

Our content is updated continuously through a multi-step peer review process that will help you be prepared and review for a thorough knowledge of PA-Hospital Medicine. When it is time for the PA-Hospital Medicine board and certification exam, you will already be ready. Besides online study quizzes, we also publish our peer-reviewed content in eBooks and mobile Apps. We also offer inexpensive CME/CE, so our content can be used to attain education credits while you study PA-Hospital Medicine.