Oesophagus+&+Stomach

Oesophagus & Stomach:
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 * Anatomical structure & location
 * Function
 * Links to other useful information (E.g. video footage or websites)
 * Revision questions

The Oesophagus
Anatomical structure & location:

The oesophagus is located between the pharynx and the stomach. It is a muscular tube about 8 inches long and is lined by mucosa; a moist pink tissue. The oesophagus can be broken into two parts: the upper oesophageal sphincter (UES) and the lower oesophageal sphincter (LES). The UES is a bundle of muscles at the top of the oesophagus while the LES is a bundle of muscles at the low end of the oesophagus.

Function:

The UES muscles are under conscious control and are used when breathing, eating and vomiting. The LES muscles keep foods and liquids from going down the windpipe (trachea). The function of the Oesophagus as a whole is to prevent acid and stomach content travelling back up. These muscles are involuntary. When food is swallowed a movement of muscles in a wave pattern occurs in the oesophagus that is known as peristalsis. The UES and LES muscles are made of a combination of striated muscle, smooth muscle and connective tissue.

Diagrams:

The Stomach

Anatomical structure & location:

The stomach is inferior to the oesophagus and superior to the small intestine. The stomach is made up of epithelium tissue and a thin layer of smooth muscle and connective tissue. The stomach is a sack made of muscle and when empty, has a volume of 50ml only however it is able to expand to between 1.5 and 2 litres. The stomach is made up of three different layers which allows it to churn food around and make sure it is mixed with acidic digestive juices.

Function:

Hydrochloric acid is present in the stomach and its fucntion is to kill any foreign bacteria in the food. The stomach also produces an enzyme called pepsin which has a specific function of breaking down proteins; the stomach uses both mechanical and chemical digestion. Food can stay in the stomach for anywhere between a few minutes to many hours in the gastric phase, where many enzymes, acids and a hormone called gastrin has churned the food up enough to make a creamy mixture also known as chyme.



Links:

The Stomach: [] The Oesophagus: []

[|http://kidshealth.org/kid/htbw/digestive_system.html#] [] []