Human Digestive systems
: Digestion & Absorption :Food is one of the basic requirements of all living organisms. (Food gives Energy to our body)
*The major components of our food are
carbohydrates,
proteins
and fats.
Vitamins
and minerals are also required in small quantities.
They have to be broken down and converted into simple substances in the digestive system.
Order of presentage-Carbohydrates >proteins >Fat >Vitamins.
*Digestion:
conversion of complex food substances to simple absorbable forms is called digestion .and is carried out by our digestive system by mechanical and biochemical methods.
(Digestion starts from Mouth and End at small intestine .There are two types of digestion, 1Mechanical Digestion, 2Chemical Digestion)
*Mechanical Digestion: Conversion of large piece of food into small part of food Called Mechanical Digestion.
* InMechanical Digestion only Conversion of large size of food in small part not at bond level break down.*Chemical Digestion: Digestion of food at bond level called as chemical Digestion.
Teeth:
A set of temporary milk or deciduous teeth replaced by a set of permanent or adult teeth.
This type of dentition is called Diphyodont.
Has 32 permanent teeth which are of four different types .
(Heterodontdentition), namely,
incisors (I),
canine (C),
premolars (PM) and
molars(M).
Arrangement of teeth in each half of the upper and lower jaw in the
order I, C, PM, M is represented by a dental formula which in human
is
2123
2123 .Adult dental formula
2122
2122 MILKEY DENTAL FORMULA
The hard chewing surface of the teeth, made up of enamel, helps in the mastication of food.
Tongue:
The tongue is a freely movable muscular organ
attached to the floor of the oral cavity by the frenulum.
The upper surface
of the tongue has small projections called papillae, some of which bear
taste buds.
The oral cavity leads into a short pharynx which serves as a common
passage for food and air.
The Oesophagus and the trachea (wind pipe)
open into the pharynx.
A cartilaginous flap called epiglottis prevents the
entry of food into the glottis – opening of the wind pipe – during swallowing.
The oesophagus/Food pipe is a thin, long tube which extends posteriorly passing
through the neck,