1. By: Hira Khan

2. A sphincter is usually a circular muscle, that normally maintains constriction of a natural body passage and which relaxes as required by normal physiological functioning.

3. There are about 5 sphincters in the gastrointestinal tract. They include:  Upper Esophageal Sphincter (UES)  Cardia/Lower Esophageal Sphincter (LES)  Pyloric Sphincter  Ileocaecal valve  Anal Sphincter - Internal - External

4.  The upper esophageal sphincter (UES) refers to the superior portion of the esophagus.  Unlike the lower esophageal sphincter, it consists of striated muscle.  It is under conscious control.

5.  Location: junction where the esophagus joins the top of the stomach  LES prevents food and stomach acid from backing up in to the esophagus and ultimately in to the trachea or “windpipe”  Involuntary

6. How the esophagus works :

7.  The pylorus is the region of the stomach that connects to the duodenum. It is divided in to two parts: The pyloric antrum: which connects to the body of the stomach The pyloric canal: which connects to the duodenum  Function:  Guards the entrance of the small intestine  The pyloric sphincter located at the end of the pyloric canal opens to allow chyme to pass through and enter the first section of the small intestine (duodenum). This is where majority of the digestion and some absorption takes place.

8.  The ileocecal valve is a sphincter muscle situated at the junction of the small intestine (ileum) and the large intestine.  Its critical function is to limit the reflux of colonic contents into the ileum.  Roughly two litres of fluid enters the colon daily through the ileocaecal valve.

9.  These sphincters keep the anal canal closed  Two types:  Internal  External

10.  This sphincter is involuntary and surrounds 2/3 of anal canal.  It is about 5 mm thick, and is formed by an aggregation of the involuntary circular fibers of the intestine. Its lower border is about 6 mm from the orifice of the anus.  The internal sphincter always contracts, the only time of relaxation, is a response to the distension of the rectal ampulla by feces or gas.

11.  Large voluntary sphincter  A flat plane of muscular fibers, elliptical in shape and intimately adherent to the integument surrounding the margin of the anus.  It measures about 8 to 10 cm in length, from its anterior to its posterior extremity.

12.  Stomach acid and enzymes flow backward from the stomach into the esophagus, causing inflammation and pain in the esophagus.  Most typical symptom is heartburn.  Treatment is avoiding trigger substances which include weight gain, fatty foods, chocolate, caffeinated and carbonated beverages, alcohol, tobacco smoking, and certain drugs  Types of drugs that interfere with lower esophageal sphincter function include those that have anticholinergic effects (such as many antihistamines and some antidepressants), calcium channel blockers, progesterone, and nitrates. Alcohol and coffee also contribute by stimulating acid production.

13.  Esophagitis – slight to heavy bleeding; blood can be vomited or may pass through digestive tract resulting in dark tarry stool (melena).  Esophageal ulcers - open sores on the lining of the esophagus, resulting from repeated reflux. They can cause pain that is usually located behind the breastbone or just below it, similar to the location of heartburn.  Dysphagia - Narrowing of the esophagus from reflux makes swallowing solid foods difficult. Narrowing of the airways can cause shortness of breath and wheezing. Other symptoms of gastroesophageal reflux include chest pain, sore throat, hoarseness, excessive salivation (water brash), a sensation of a lump in the throat (globus sensation), and inflammation of the sinuses (sinusitis).

14.  Ileocaecal valve is stuck open causing waste products to back up in to the small intestine.  Symptoms:  Nausea, Headache, Bad breath, Dizziness, Bowel disturbances (diarrhea/constipation), Dark circles, Flu symptoms etc.  Causes:  Dehydration, emotional upsets, How you eat (overeating, eating too frequently, not chewing properly), Foods you eat (carbonated drinks, alcohol, caffeine, chocolate, raw food, hot spicy food)  Treatments:  Homeopathy, Temporary elimination of certain foods from diet eg. Roughage foods, raw fruits and vegetables, spicy food and stimulants.

15.  Severe vomiting in the first few months of life. Narrowed opening between stomach and intestines due to enlargement (hypertrophy) of the muscle surrounding the pylorus which spasms when the stomach empties.  Symptoms:  Projectile Vomiting, weight loss, dehydration  Causes:  Gender of the baby (occurs 5x more in boys than girls), family history of condition, genetic abnormalities etc  Treatment:  Pyloromyotomy (divides the muscle of the pylorus to open up the gastric outlet)

16.  http://www.merck.com/mmhe/sec09/ch120/ch120a.html  http://www.merck.com/mmhe/sec09/ch121/ch121d.html  http://www.bodyandhealth.canada.com  http://www.aboutgimotility.org/site/about-gi-motility/disorders-of-the- pelvic-floor/