Nutrition in Human beings:
The
soft food mixed with saliva passes through oesophagus or food pipe by wave like
movements called peristaltic movement to the stomach. At the stomach, food gets
churned with gastric juice and HCI. Now the food is in semisolid condition. The
digestion of food goes on as mo proteins are broken down into smaller molecules
with the help of enzyme pepsin acting on
them.
Digestive Enzymes:
Flow chart of human digestive system
What
do you think is the process of digestion?
What
are its major steps?
In
single celled organisms the food may be taken in by the entire surface but as
the complexity of the organism increases different parts becomes specialized to
perform different functions.
The
large complex food molecules such as carbohydrates, proteins, lipids, etc., are
broken down into simple molecules before they are absorbed and utilized by the
animals. This process of breaking down of complex molecules into simple
molecule is called digestion.
In
human beings the food eaten is broken do in various steps with the help of
enzymes secreted by digestive glands which are associated with the alimentary
canal and the digested food is absorbed in small intestine to be sent to all
cells in the body.
The
digestive system includes the alimentary tract and several associated organs
and digestive glands. The functions of system are as follows:
a)
Ingestion: Taking of food into the
body
b) Digestion: Breaking up of complex
food substances into the simple substances by specific enzymes. So that they
can be used by the body.
c)
Absorption: The passage of digested
food through the walls of alimentary tract (particularly in small intestine)
into circulatory system
d) Defecation:
The passage of undigested material from the body by the way of anus.