Fibre-rich foods include: Bran-rich breakfast cereals Brown bread, brown rice and brown pasta Fresh fruit and vegetables.
l l l
Processed and refined foods are not a good source of fibre. A diet high in these types of food can lead to constipation and other health problems like obesity.
Bacteria in the large intestine There are billions of bacteria living in the large intestine. They benefit us in many ways. For example: They break down undigested carbohydrates. They produce vitamins B and K. They prevent disease-causing bacteria from growing in the large intestine.
l l l
10.10 Interactions of the digestive system
The digestive system works with the circulatory system to provide food molecules to the body. The villi in the small intestine are very thin and have a dense network of capillaries, allowing simple food molecules to be absorbed through the walls of the small intestine into the blood. The circulatory system transports these simple molecules to the liver and to the rest of the body where they are used for energy, growth and repair. The circulatory system transports the water absorbed from undigested food in the large intestine around the body. The liver releases wastes into the blood for transport to the excretory system where they are removed from the body.
Nature of Science
In this chapter you constructed a simple model to explain peristalsis. You also researched the health problems associated with obesity, and designed a campaign to raise awareness about this problem. Question: Do you think model-making plays an important role in science? Give a reason for your answer.
