Bowel how long

When the rectum is full, the nerves sense this fullness and then inform the brain whether this is due to gas or stool. When we need to go to the toilet, the brain tells the anal sphincter muscles, via the nerves, to relax. As the muscles relax, the anus opens and the rectum empties. In some neurological and spinal conditions the brain cannot tell whether the bowel is full of waste faeces or just wind. This can lead to accidental leakage.

The anal canal is about 3 — 4cm long in women and sometimes slightly longer in men. The internal and external sphincters form 2 concentric rings which run along the length of the anal canal. The internal anal sphincter IAS is made of smooth muscle and we do not have voluntary control of this muscle. It works automatically to keep the anus closed until we are ready to have a bowel movement. The external anal sphincter EAS is made of striated muscle the same as the pelvic floor muscles ; we do have voluntary control over the EAS — allowing us to hold on if we are aware of wind or diarrhoea.

The pelvic floor muscles are layers of muscle stretched like a sheet from the pubic bone in the front, to the bottom of the backbone coccyx. There are 3 openings through the pelvic floor in women and 2 in men -the anus back passage , the vagina in women birth canal and the urethra bladder outlet. The muscles support these 3 openings, but if they are weakened or not in good condition they cannot support the openings effectively. One of the muscle groups within levator ani is the puborectalis.

This muscle forms a supportive strap around the junction between the rectum and the anal canal and helps to keep us in control of our bowels by forming a flap like valve, which prevents stool passing too easily into the anal canal. The brain tells the bowel what to do by sending electrical signals to the muscles in the pelvic floor, the sphincters and the urethra.

The commands from the brain to the bowel colon are sent as electrical impulses and are carried by a system of special fibres called nerves. It is located toward the bottom of the abdomen and connects the stomach to the large intestine. The small intestine makes digestive juice to complete the breakdown of food. It also absorbs water and nutrients.

If the small intestine is unable to absorb enough water, a person may get diarrhea. The small intestine consists of three distinct parts :. It is difficult to measure the length of the small intestine in a healthy living person, but researchers estimate that it ranges from about 9. The three sections of the small intestine differ significantly in length:. Older research found that the total length of the intestines correlates with weight, such that people who weigh more have longer intestines.

Younger people and males also have, on average, longer intestines. The small intestine is long enough that a person can undergo small bowel resection surgery to remove part of it if an underlying disease or condition causes it to stop functioning. The large intestine , which doctors also call the colon, has a larger diameter than the small intestine.

The primary function of the large intestine is to reabsorb fluids, electrolytes, and vitamins and then form and propel feces toward the rectum for elimination.

It contains four distinct parts:. As with the small intestine, the total length of the large intestine varies from person to person. Heavier people, younger people, and males generally have longer intestines. In most people, it is about 5 ft long. The colon is the longest part of the large intestine, while the cecum measures about 2. The rectum is about 7. Some people with certain health conditions may need to undergo a colon resection , or colectomy, to remove part of or the whole large intestine.

Answer From Elizabeth Rajan, M. Thank you for Subscribing Our Housecall e-newsletter will keep you up-to-date on the latest health information. Please try again. Something went wrong on our side, please try again. Show references Goldman L, et al. Disorders of gastrointestinal motility. In: Goldman-Cecil Medicine. Elsevier; Accessed Nov.

Normal function. International Foundation for Gastrointestinal Disorders. Naish J, et al. The alimentary system. In: Medical Sciences. See also How digestion works Swallowing gum: Is it harmful?