Organ Systems Pt 2 - Digestive

Organs in the digestive system : functions , structure , cells and tissues

Introduction

Digestion is a very important daily function in human beings and indeed all animals . The Bioengineering Institute (2008 ) divides the organs in the digestive system into two groups , namely those of the gastrointestinal tract and the accessory organs . The organs of the gastrointestinal tract are : mouth pharynx oesophagus stomach small intestine and large intestine while the accessory organs are : teeth tongue , salivary glands , gallbladder , liver and pancreas

Functions of the digestive system

The functions of the digestive system are

as follows

Mastication

Breaking down the food that is taken into the mouth in the mechanical and chemical process through mastication . This way the food is ready for the next stage in digestion

Contraction and swallowing

The oropharynx and laryngopharynx is responsible for swallowing when the muscles in these organs contract and relax , they create a peristaltic valve

Conveying found to the stomach

The oesophagus conveys the food to the stomach

Chemical digestion and absorption into the blood

Chemical digestion takes place in the stomach which is a temporary storage for food . In the stomach , food is converted into chyme ' and it is absorbed into the blood stream via the walls of the stomach

Digestion

Digestion and final absorption into the blood stream occurs in the small intestine (which is said to be the body 's main digestive organ

Secretion of enzyme

Enzymes which facilitate digestion are secreted in the stomach and small intestine . These enzymes come from ducts in the bile , gall bladder and pancreas

Absorption of water and excretion

Water is absorbed from the undigested residue in the large intestine and finally excreted via the anus

Structure of the digestive system

The Cleveland Clinic (2005 ) writes that the digestive system is structured to turn food into energy and waste product which is passed out through the anus . Food enters the mouth and is passed via the oesophagus to the stomach where it is broken down . Further more secretions from the bile , pancreas and gall bladder further digest the food and aid absorption into the blood stream . Vibrant Life (2003 ) adds that digested food is emulsified by bile . Then the food passes into the colon and large intestine where water is removed from undigested food and it is passed out as excreta through the anus

Cells and tissues of the digestive system

The tissues in the digestive system are : the mucosa , submucosa muscularis externa and the serosa . The mucosa (which is made up of three layers- lining epithelium , lamina propria , and muscularis mucosae ) is a moist membrane that lines the walls (lumen ) of the gastrointestinal tract . It secretes enzymes and hormones that absorb digested products into the blood stream

The submucosa is elastic and enables the stomach maintain its shape after a large amount of food has been digested away from the stomach The muscularis externa propel the food along the gastro-intestinal tract . The serosa forms a protective layer in the gastrointestinal tract

In the digestive tract there are...