Ascending Colon

The ascending colon constitutes one of the 4 main sections of the colon which in turn is a component of the large intestine. It takes feces superiorly from the cecum across the right section of the abdomen into the transverse colon. Bacteria present in the ascending colon help digest the fecal matter which is passing through as well as produce vitamins. The wall of the intestine absorbs nutrients, water, and vitamins from the fecal matter and later deposits such substances into the bloodstream.

The anatomy, structure, and function of ascending colon

  • The ascending colon is a tubular hollow structure which measures around 8 inches in length and about 2 ½ inches diametrically. The surface area along its length is increased via the occurrence of several tiny pouches. The lower end of the ascending colon attaches to the large intestine’s cecum in the abdominal cavity’s right iliac area. The ascending colon then superiorly moves upwards from the cecum towards the liver’s right lower rim. Just prior to arriving next to the liver, it take an almost 90 degree turn at the hepatic flexure, to the left. From here, the ascending colon runs forward as the transverse colon.
    • The ascending colon’s innermost layer consists of the mucosa, which in turn consists of epithelial tissue. Mucosa secretes mucus via the goblet cells so as to offer lubrication for the fecal matter going across the lumen. The mucosa cells absorb water and vitamins from feces and pass them to the nearby capillaries filled with blood.
    • The sub-mucosa layer is located deeper to the mucosa; it is made up of nerves, blood vessels and connective tissues that offer support to the mucosa. The sub-mucosa layer is enclosed in the muscularis layer which offers many smooth muscle tissue layers that help pass food across the colon by way of peristalsis. Contraction of the muscularis smooth muscle is what forms the pouches present in the colon.
    • The ascending colon’s outermost layer is enclosed on the anterior side by the peritoneum, while the areolar connective tissue covers the back section. These tissues help ensure that the colon stays in its place. They also offer protection for the colon from friction arising due to movement of the body as well as blood vessels for the colon.
  • By the time digested food arrives at the large intestine, nearly 90 percent of its nutrients are already absorbed. The food then combines with bacteria present in the cecum to become feces. The feces is then slowly moves forward across the ascending colon’s length by waves of peristalsis. During this process of feces passage across the ascending colon, the waste material which cannot be digested by the body gets digested by the bacteria and release vitamins B1, K, B12, and B2. Along with the water content in the feces, the colon walls absorb the vitamins thus liberated. In healthy individuals, the waste materials will pass into the colon as chunky liquefied water and get out of it as solid condensed waste. Water absorption by the colon is instrumental in maintaining the body’s water homeostasis, thereby avoiding dehydration.

Disorders of the ascending colon

The ascending colon may suffer from a variety of conditions. The most common ones are listed below:

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  • Crohn’s Disease: It is a chronic illness marked by digestive tract inflammation, particularly inflammation of the large and small intestines. All the layers of the ascending colon can get affected by Crohn’s disease. Normal and healthy colon tissue may be seen to occur between sections of diseased colon tissue/areas.
    • Patients may experience symptoms such as pain in abdomen, diarrhea, blood stool, abdominal cramping, lack of appetite, and ulcers. Severe instances may also be accompanied by fatigue, fever, ocular inflammation, arthritis, and skin conditions.
  • Ascending colon polyps: Polyps are fleshy growths which may jut out from the colonic wall. If left untreated, they can become bigger, become malignant, and cause colon cancer. It is recommended for all individuals over 50 years of age to get regularly tested for presence of polyps.
  • Diverticulitis: It is a condition marked by inflammation of the diverticula which are the pouches that form on the lining of the ascending colon and other sections of the intestines. The pouches can develop on any section of the digestive tract, but most commonly forms in the colon. Diverticula can also occur without any inflammation or other adverse symptoms.
    • Diverticulitis is marked by symptoms like fever, extreme pain in abdomen, marked changes in bowel movements and functions, and nausea. Mild cases can be treated with medication and diet and lifestyle changes, while severe cases may require surgical treatment.
  • Colon cancer: The ascending colon may sometimes form a mass or tumor; in most cases such tumors are colon cancer. Affected persons may experience the symptoms of the malignancy only after the cancer has reached the advanced stages, often because the fecal matter in this section of the colon is mostly in liquid form, thereby not causing any adverse colonic obstructions.
    • Nearly 30 percent of all growths, whether benign or malignant, that affect the rectum or the colon occur in the ascending colon. The wider diameter of the ascending colon also means that tumors affecting the area tend to grow very large before being finally diagnosed. Surgical removal of the tumor and the affected section of the colon, along with radiation therapy and/or chemotherapy are the treatment options for non-cancerous or malignant ascending colon tumors.
  • Ulcerative colitis: This condition of the ascending colon is marked by development of ulcers, sores, or inflammation of the inner lining of the colon and the large bowel. Inflammatory damage of the cells lining the colon wall can trigger the formation of ulcers which then bleed and release pus. This may then cause frequent and sometimes painful bowel movements.
    • The condition can occur at any age, but is often seen in the 15 to 30 years age group. It is common in both gender. Caucasians and people of Jewish ancestry are more prone to developing the condition.
    • Patients may suffer from symptoms such as fatigue, anemia, low appetite, loss of weight, rectal bleeding, pain in joints, and lesions on the skin.
  • Drinking lots of water, eating a healthy and balanced diet containing vegetables and fruits, and regular exercising can help maintain the overall health of the digestive system and prevent the onset of disorders of the ascending colon.


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