What Is Considered the Colon?

What Is Considered the Colon?

anatomical structure of the colon

The colon, also known as the large intestine, is responsible for the last stage of digestion, such as the removal of waste products from the human body.

The colon is also known as the large intestine, which along with the small intestine makes up the digestion system in the human body.

  • During digestion, the small intestine, which is the continuation of the duodenum, helps with additional processes of digestion and absorption of nutrients.
  • The large intestine is responsible for the last stage of digestion such as absorption of water, electrolytes, and vitamins and removal of waste products that cannot be used by the body.

What is the anatomical structure of the colon?

The colon is significantly larger in circumference than the small intestine, but it is significantly shorter in length.

  • The small intestine is 22 feet (6.7 meters) long.
  • The colon is only about 6 feet (1.8 meters) in length.

This dense muscle is divided into four sections:

  1. Ascending colon
  2. Transverse colon
  3. Descending colon
  4. Sigmoid colon

The following three arteries supply blood to the colon:

  1. The ileocolic artery is responsible for supplying blood to the initial part of the colon.
  2. The middle colic artery delivers blood to the colon’s second section.
  3. The inferior mesenteric artery delivers blood to the colon’s third section.

Each of these arteries is accompanied by veins.

Lymph nodes

Lymph nodes function as filters, removing dead cells, bacteria (germs), and even cancer cells from the body and preventing them from entering the bloodstream. They are situated around the colon’s arteries and veins.

Lymph nodes may need to be removed. If cancer is discovered in the colon, cancer cells can be evaluated in the lymph nodes. This will aid in determining the stage of cancer and whether more therapy is required.

What are the different parts of the colon?

The colon is divided into seven parts:

  1. The cecum is the beginning of the colon. It’s on the bottom right side of the abdomen.
  2. The ascending colon is referred to as the right colon and is the first section of the colon.
  3. The transverse colon is the colon’s central section.
  4. The third section of the colon is the descending colon, which is referred to as the left colon.
  5. The sigmoid colon is the colon’s last section.
  6. Stool passes through the rectum, which terminates at the anus.
  7. The anus is the orifice at the end of the colon. The stool is expelled from the body through the anus. Bowel movements are controlled by the muscles and nerves in the rectum and anus.

What are the functions of the colon?

  1. Removal of solid waste:
    • The large intestine’s role is to eliminate food (that has been left over after the nutrients have been extracted), bacteria, and other waste. This procedure is known as peristalsis and can take up to 36 hours.
    • First, as the waste moves through the colon, moisture and salt are removed from it. The waste is then transported to the sigmoid, where it is stored. When the body is ready for a bowel movement, waste is released into the rectum one or two times every day.
  2. Gut immunity:
    • The large intestine (colon) is the reservoir of numerous commensal microorganisms that help with your immunity.
    • The colonic immune system involves the production of a thick mucus layer, generation of immunoglobin A type of antibodies, and presence of a large number of regulatory T cells that recognize these potential hazards and regulate your overall health and wellness.


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What are the possible diseases to the colon?

There are multiple factors and disorders that affect the colon, which include:

What are the symptoms of colon diseases?

Symptoms of colon disorders include:

What are the treatment options for colon diseases?

The treatment of colon diseases depends on the type of the disease.

Lifestyle modifications can be done such as:

Surgery may be done for certain conditions such as:

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How to diagnose colon diseases

To determine the type of colon disease and know the extent of the severity of the disorder, the doctor will first perform a thorough medical history and physical examination.

The doctor may use diagnostic tests to help build a treatment strategy for your condition.

  • Abdominal ultrasound: Ultrasound waves are used to detect the presence of any mass in the intestine. The mass may be caused by an underlying tumor or impaction of stools. 
  • Barium enema: Enema is performed by injecting barium solution into the colon. Once the radioactive element settles, X-rays are taken. This procedure is also known as the lower gastrointestinal series.
  • Colonoscopy: A colonoscope is a thin, flexible tube that is used to examine the inner lining of the large intestine. This test can detect ulcers, polyps, tumors, and areas of inflammation or bleeding. Biopsies (tissue samples) can be gathered, and abnormal growths can be removed. This test can be used to check for colon or rectum cancer or precancerous growths (polyps).
  • Sigmoidoscopy: Doctors use special tools to look inside the rectum and portion of the large intestine closest to the rectum.
  • Capsule endoscopy: This provides an enhanced view of the lower digestive tract that a standard colonoscopy may not provide.
  • Radiological tests: Other radiological tests such as computerized tomography, magnetic resonance imaging, positron emission tomography, and X-ray scans are done to study the colon.


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Medically Reviewed on 1/21/2022


Image Source: iStock Images

The Colon: What it is, What it Does and Why it is Important: https://fascrs.org/patients/diseases-and-conditions/a-z/the-colon-what-it-is,-what-it-does

Colon: https://www.sciencedirect.com/topics/medicine-and-dentistry/colon