Where is bowel in human body

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Login Skip Forgotten your password? Forgotten password Hi supporter , do you want to send a password reminder?. Send Password Reminder. JustGiving Login Hi supporter , please enter your JustGiving login details below and we'll handle the rest. After food has travelled along the gut, it has become digested and the nutrients and fluids absorbed; the waste is then expelled through the rectum and anus.

The rectum and the upper portion of the anal canal are richly supplied with nerves. 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. Diagram of the digestive system. See also Bowel cancer. The small bowel The small bowel is part of the digestive system. The small bowel is made up of three main parts: the duodenum — the top section that is joined to the stomach the jejunum — the middle section the ileum — the lower section that is joined to the large bowel.

Diagram of the position and sections of the small bowel. The colon The colon is divided into 4 sections. Ascending colon The first part of the colon is joined to the small bowel and goes up the right side of the abdomen tummy. Transverse colon The second section goes across the abdomen from your right to your left side.

Descending colon The third section goes down the left-hand side of your abdomen. The rectum The rectum links the colon to the anus. It is about 15cm 6 inches long. To help describe where a cancer is, doctors divide the rectum into three: the upper, middle and lower third. The upper third is the section directly after the sigmoid colon. The lower third is where the large bowel joins the anus. The middle third is in between.

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Our Sites. Intestine Transplant. What Is the Small Intestine? The small intestine is made up of three segments, which form a passage from your stomach the opening between your stomach and small intestine is called the pylorus to your large intestine: Duodenum: This short section is the part of the small intestine that takes in semi-digested food from your stomach through the pylorus, and continues the digestion process.

The duodenum also uses bile from your gallbladder, liver, and pancreas to help digest food. Jejunum: The middle section of the small intestine carries food through rapidly, with wave-like muscle contractions, towards the ileum. Ileum: This last section is the longest part of your small intestine. The ileum is where most of the nutrients from your food are absorbed before emptying into the large intestine.

How can the small intestine digest so much? The small intestine has three features which allow it to have such a huge absorptive surface area packed into a relatively small space: Mucosal folds: The inner surface of the small intestine is not flat, but thrown into circular folds. This not only increases the surface area, but helps regulate the flow of digested food through your intestine. Villi: The folds form numerous tiny projections which stick out into the open space inside your small intestine or lumen , and are covered with cells that help absorb nutrients from the food that passes through.

Microvilli: The cells on the villi are packed full of tiny hairlike structures called microvilli. This helps increase the surface of each individual cell, meaning that each cell can absorb more nutrients.