digestive system

Topics: Digestion, Stomach, Digestive system Pages: 12 (3138 words) Published: December 9, 2013
Digestive System
 
Digestive system includes the stomach, liver, pancreas, duodenum, ileum and colon.  
What is a Digestive system?
 
Digestion is a breakdown and transportation of the solid and liquid food into microscopic substances therefore theses substances are then transported into different areas of the body  
The digestive system is a set of organs which transforms whatever we eat into substances that can be used in the body for energy, growth and repair.  
Once the food has been broken down by the various chemical processes, and nutrients removed, the rest is excreted as waste.  
The whole process involves many different organs and sometimes takes several hours.  
There are four stages of digestion:-
 
        Mouth: ingestion (taking in of food or liquid into the body), chewing and swallowing this is the starch of digestion.  
        Stomach: mixing and protein digestion
 
        Small Intestines: carbohydrates and fat digestion abortion  
        Large intestine: waste and excretion
 
Reference:
http://en.wikipedia.org/wiki/Digestive_system
Website viewed on 28 / 5 / 08
 

Reference:
http://training.seer.cancer.gov/module_anatomy/unit10_3_dige_regions.html Class notes hand out 26 / 2 / 2008
Web sight viewed on 27 / 2 2008
 
Where Does Digestion Start?
 
The digestion starts within the mouth where the action of the teeth and saliva combined in the first stage of breakdown which is chewing and partially digesting the food so that it can pass threw more easily along the oesophagus therefore the ball of the food that leaves the mouth is known as bolus.  

Saliva
 
        The salvia is a liquid secreted by three pairs of  
        The parotid gland placed below the ear
 
        The submandibular gland and the sublingual gland both of these are placed below the tongue.  
        It contains water, mucus and enzyme salivary amylase.  
The Three Functions of the Saliva
 
        To lubricate the food with mucus, making it easier to swallow         To start digestion: it contains the enzymes salivary amylase, these acts on cooked starch turning it into shorter polysaccharides.         To keep the mouth and teeth clean.

 
Reference:
http://en.wikipedia.org/wiki/Digestive_system
Website viewed 29 / 5 / 08
 
 
Tongue
 
 
The Structure of the Tongue
 
The tongue is a muscular organ that is covered with a membrane.  
It is held in place by attachments to the mandible (lower jaw) and the hyoid bone.  
Tiny projections known as papillae cover the top, increasing its surface area and producing a rough texture.  
At the side and the base of the tongue, as well as the palate and at the back of the throat there are special areas known as taste buds.  
The Function of the Tongue
 
        The tongue has tree digestive functions: - taste, chewing and swallowing  
        Taste: the tongue is covered with thousands of taste buds which are sensitive to salt, sweet, sour and bitter chemicals within the food and drinks.         They help us enjoy what we eat and drink and also acts as a first line of defense, warning us when food and drinks are foreign matter are off or unfit for human consumption.  

        Chewing: the tongue aid is by moving food around the mouth, pushing it between the teeth and covering it with saliva, which contains enzymes that starts the digestion process.         The food is turned into a partially digested mass known as a bolus.  

        Swallowing: when the food is ready to travel to the stomach, the tongue pushes it to the back of the mouth.  
Reference:
http://family.innocentdrinks.co.uk/newsletters/2007/august/  http://www.eatatease.com/themouth.html
Website viewed on 30 / 5 / 08
 
How does food travel from the mouth to the stomach?
 
        The action of swallowing and through the tube is known as the oesophagus.  
        The tongue pushes the bolus to the back of the mouth, towards the pharynx, muscular tube behind...
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