The Breathing System

Question 0

Respiration

Answer 0

Respiration is a chemical process which releases energy from glucose. It occurs in all living cells and requires oxygen while it produces carbon dioxide and water.

Question 1

The breathing system

Answer 1

RESPIRATION AND BREATHING

  Breathing is the way in which animals take in oxygen and release carbon dioxide and water. Breathing takes place using the breathing system.

The breathing system
When we breathe in, oxygen passes from our lungs into our bloodstream. The blood then carries oxygen to all the cells of our body. Oxygen is used in each cell to carry out respiration.
Carbon dioxide and water vapour are produced by respiration in each body cell. They enter the bloodstream and are carried by the blood to the lungs.
Carbon dioxide and water vapour pass from the blood into the lungs and are then breathed out.
In this way the breathing system supplies oxygen for respiration and gets rid of the waste products of respiration. As a result the breathing system is also called the respiratory system.

Question 2

Functions

Answer 2

Nose
We are supposed to breathe in (inhale) through our nose. The reasons for doing this are:
Hairs and mucous in the nose trap dirt particles and bacteria.
Air is warmed and made moister as it passes through the nose. This later helps oxygen to pass from the lungs into the bloodstream.

Trachea or windpipe
The trachea or windpipe carries air to and from the lungs.

Question 3

Functions

Answer 3

Bronchus and bronchioles
Each bronchus carries air between the windpipe and a lung.
The two bronchi subdivide many times to form tiny tubes called bronchioles. Bronchioles carry air to and from the air sacs or alveoli.

Alveolus
Each lung contains millions of tiny air sacs called alveoli. Each alveolus has a thin lining and is surrounded by many tiny blood vessels called capillaries. The function of the alveoli is gas exchange.
Oxygen passes from the air in the alveolus into the blood vessels. At the same time carbon dioxide and water pass from the blood vessels into each alveolus. The gases pass in each direction by a process called diffusion.
As a result of gas exchange in the alveoli, the contents of inhaled air are different to the contents of exhaled air. The approximate figures are given in Figure 5.8.