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Your bowel and spinal cord injury Tools

Your digestive system - the facts

Your body receives its nutrients through your digestive system, and your bowel is responsible for getting rid of waste products. Spinal cord injuries commonly cause alterations in bowel function, but good management can minimise and prevent many of these.

When you damage your spinal cord other body functions are also affected. You will still maintain feelings of hunger or fullness in your stomach; however, messages of when your bowel is full or needs to be emptied will not be the same. This means that the voluntary control of your bowel is affected and you will not recognise when you need to go to the toilet or will not be able to consciously control the muscles and sphincters to empty your bowel.

Bowel care is one of the most difficult and embarrassing subjects for you to deal with. A nurse will work with you in hospital to set up a reliable bowel routine that fits your lifestyle in the community and avoids complications.

Digestion is the way your body receives the nutrients it requires for healing and manufacturing hormones and enzymes, as well as the energy for your physical activities.

Your digestive system has a number of different sections:

  • mouth
  • oesophagus
  • stomach
  • small intestine
  • large intestine

All of these are connected via your gastrointestinal tract. This is a tube-like structure with a smooth muscle wall. It is lined by mucous membrane.

 

After food is chewed in the mouth it passes down your oesophagus and through your gastrointestinal tract, where it is broken down into small enough parts to be absorbed into your body through your tract walls. This occurs through both mechanical and chemical means.

  • Mechanical digestion occurs through your teeth (chewing), the churning of food in your stomach and peristalsis, a series of contractions in your gastrointestinal tract that move food along.
  • Chemical digestion occurs with acid in your stomach and digestive enzymes produced in your tract, pancreas and gallbladder.

Stomach

The stomach is a J-shaped section of your gastrointestinal tract. Your oesophagus connects your mouth to your stomach. Partly digested food travels down your oesophagus to your stomach. The muscles of your stomach contract, churning the food, continuing its mechanical digestion.

Your stomach holds and churns food for many hours as hydrochloric acid and stomach enzymes chemically break the food down. The food is slowly converted into a liquid known as chyme. This passes from your stomach into your small intestine for further digestion.

 

Small intestine

Your small intestine is approximately 3.5 metres long and is divided into three sections:

  • duodenum
  • jejunum
  • ileum

Chyme passes from your stomach into your duodenum. Your gall bladder and pancreas release large amounts of fluid into your duodenum, consisting of bile and pancreatic juices. This fluid assists with the breakdown of carbohydrates, proteins and fats.

This is where the absorption of nutrients, vitamins and minerals from your digested food takes place. This process takes many hours, and then the remaining chyme is delivered by peristalsis into your large intestine.

Large intestine

Your large intestine is the last section of your gastrointestinal tract. It is about 1.5 metres in length and 6.5 centimetres in diameter, and is divided into four parts:

  • caecum
  • colon
  • rectum
  • anal canal

Between your small and large intestine is the ileocaecal valve. This opens and closes to allow chyme to pass through into your caecum. Chyme then passes through the length of your colon, where it is further processed until only waste remains. This remaining waste is faeces and is stored in your colon.

Colon

Your colon is the major storage area of the bowel. It has four distinct areas:

  • ascending colon
  • transverse colon
  • descending colon
  • sigmoid colon

Rectum

Your rectum, the last part of your gastrointestinal tract, is at the end of your sigmoid colon. It is about 20cm long.

Your anal canal is at the end of your rectum. It is a narrow section, about 2-3cm long. The anal canal has both an internal anal sphincter, and an external anal sphincter. The external opening is called the anus.

Reflexes

The gastrocolic reflex helps chyme to move from the transverse colon into the descending colon, pushing waste from the sigmoid colon into the rectum.

Peristalsis helps to move chyme through your colon and other reflexes (such as the gastrocolic reflex) become active when you eat. These reflexes assist chyme to pass through your digestive system, eventually assisting in evacuation of the large intestine through the defecation reflex.

The presence of waste (faeces) in your rectum stimulates stretch receptors (sensors) which set off the defecation reflex. This assists in the evacuation of faeces from your large intestine. This is called defecation, which is called a bowel action or movement.