The oesophagus receives the food pushed by the swallowing action of the mouth.

What are the systems that come into play for swallowing food?

The following schematic representation shows some functional and stuctural attributes of oesophagus. Observe it and answer the following questions.

What does the schematic diagram tell us about the oesophagus?

What kind of the tube is oesophagus?

How does mucus help in passage of food?

Activity-9

Take a pice e of waste cycle tube. Lubricate the inner side of the tube with oil. Insert one or two oil coated potatoes in the tube. Now try to push the potatos by squeezing the tube.

How do you squeeze the tube to make the potatoes pass through?

How did the oil work?

Do you think that the muscles in the wall of the oesophagus have to do something like this?

How did oil help you in pushing the potatoes through the pipe?

Look at the fig-6, which shows wave like movement of wall of oesophagus and observe the position of the food bolus.