1st Entry

Now that since my Biology Topic is 'Digestion',I will thus start with a very broad question.

What is Digestion?

Now since Digestion is a very HUGE Topic (Thats why Its one of the 4 topics given anyway,isn't it?lol),we will thus be splitting it into a couple of entries.

1st entry:

Before we actually go into the details,we first need to know how our digestive system is like.Therefore,introducing as the main thing for this entry...

The Human Digestive System!

Another name for it is the Gastrointestinal tract,or Digestive tract.

Here is a very basic picture to show you how it looks like:


We will be touching on...

The Mouth
Picture courtesy of maniac world.


The mouth plays a few roles in our lives,and that is to:

1.Help express feelings.I can't imagine somebody getting angry and there is no mouth to emphasize "I AM VERY ANGRY AT YOU" by giving a grimace or a frown

2.For speech

3.For eating

Now for a more detailed picture of the mouth:

Incisors: These are teeth which you use to chew and rip your food into bits,so that they can enter the esophagus easier.This also helps allow digestion to be faster as smaller food bits have larger surface areas.

Soft palete: These close off the nasal passages when you swallow.

Uvula: It plays a key role in the articulation of your voice to form sounds of speech.

Tonsil: They are part of the immune system to help protect against infections.

Tongue: It helps you in speech,and in digestion it is to secrete enzymes found in saliva to break down the food.The saliva makes the food moist to make swallowing easier and the food can go down the gullet easier as well.It also has taste buds to help you choose which food to eat-I doubt most poisons taste sweet,do they?

Video:



Can't catch a word?Never mind!

The mouth is the beginning of the digestive system. It is here that the first stages of food breakdown begin. When food enters the mouth, saliva, a fluid containing the digestive enzyme ptyalin and mucus, is secreted by the salivary glands. Saliva not only lubricates the food and begins its chemical digestion, but it also helps to keep the mouth cavity moist and clean. The teeth function mechanically to break up the food into smaller, more readily swallowed and digestible pieces. The tongue and the muscular walls of the mouth shape the food into a moist ball, the bolus, which is pushed to the back of the mouth and into the pharynx to be swallowed.

Word FOR Word. =)


Extra information on how your mouth actually chews the food:



Links:
http://www.enchantedlearning.com/subjects/anatomy/digestive/
http://en.wikipedia.org/wiki/Gastrointestinal_tract
http://en.wikipedia.org/wiki/Mouth
http://en.wikipedia.org/wiki/Soft_palate
http://en.wikipedia.org/wiki/Palatine_uvula
http://en.wikipedia.org/wiki/Tonsil
http://en.wikipedia.org/wiki/Incisor
http://www.maniacworld.com/Scary.html
http://wiki.answers.com/Q/The_role_of_tongue_in_digestion
http://www.youtube.com/watch?v=YiXW8jn71gE&eurl=http%3A%2F%2Fbiochembloggie.blogspot.com%2F&feature=player_embedded
http://www.youtube.com/watch?v=tvpLj5Tcnig&eurl=http%3A%2F%2Fbiochembloggie.blogspot.com%2F&feature=player_embedded