digestive system is the system which helps in digestion and absorption of food particles. Digestion is the process of breakdown of food into small molecules, which are then absorbed into the body.
NEED OF DIGESTIVE SYSTEM ?
The food that we consume cannot be directly absorbed by the body so the process of digestion occurs which helps in breaking down of large food particles into soluble absorbable for.
THE DIGESTIVE SYSTEM
The digestive system consists of the alimentary canal and the digestive glands.
a) alimentary canal: the alimentary canal starts from the mouth and ends at the anus which is around 9 meters long or 29 feet long.
the mouth
the mouth or the oral cavity consists of the lips, the tongue and the teeth. It is the place where the food is chewed and mixed with the saliva. lets discuss about them and know some interesting fun facts about them.
- lips: the upper and the lower limits of the mouth is called the lips. Functions of lips are i) closing the mouth ii)sucking and sipping the liquids iii) it helps in speaking.
- tongue: it is the strongest muscle of our body i) it helps in manipulating the food and mixing it with the saliva. ii) it helps in tasting the food as it contains different taste buds which helps in detecting tastes like sweet, sour, bitter and salty. iii) it also helps in speaking (try this act catch your tongue with your hand and try to speak ).
- teeth: it helps in cutting, biting, grinding food and breaking it into smaller particles. An adult human contains around 32 teeth. There are 4 types of teeth they are i) Incisors ii) Canines iii) Premolars iv) Molars Each of them are being discussed down briefly.
- i) Incisors: there are 4 incisors in each jaw (upper jaw and lower jaw). the front four tooth are called the incisors. functions of incisors are: it helps in cutting and biting.
ii) canines: there are 2 canines in each jaw they are located just beside the incisors. They help in tearing and holding food.
iii) premolars: there are two after each canines on either side of a jaw. Grinding and crushing are the important functions of premolars.
iv) molars: the last three teeth of a human body is known as molars. They are principal grinders and crushers. There are two tooth present in a teenagers however the last tooth that is wisdom tooth grow during 17-24 years of age.
STRUCTURE OF A TOOTH :
* part above the gum is called crown.
* part below the gum is called root.
* a slight construction between crown and root is called neck.
PARTS OF A TOOTH :
* Enamel: i) hardest substance of the body. ii) It protects the inner teeth from breaking while eatingany hard food.
*Dentine : i) it is located just below the enamel.
*Cement : i) fixes the tooth in the root . it is a bone like structure.
* Pulp : i) present in the pulp cavity. ii) contains nerves and blood vessels.
study den 