Download the respiratory system

THE RESPIRATORY
SYSTEM
Learning Objectives
 To state the function of the Respiratory
System.
 To describe the structure and workings of
the Respiratory system.
 To name the major parts of the
Respiratory System.
 To describe the effects of physical activity
on the Respiratory System.
What are the functions of the
Respiratory System?
 Inspiration or breathing of air into the
lungs.
 Exchanging oxygen for Carbon Dioxide
with the Circulatory system in the lungs.
 Expiration or breathing out of air from the
lungs.
What makes up the Respiratory
System?




The nasal Cavity
Air passages
The lungs
The diaphragm.
Structure of the Human
Respiratory System
The respiratory system in human beings can
be divided into the upper respiratory tract
that consists of the nasal passages, pharynx
and the larynx and the lower respiratory tract
that is composed of the trachea, the primary
bronchi and the lungs.
The Upper Respiratory Tract
 Nose (nostrils) - It is the entrance of the
respiratory tract.
 Pharynx - It is situated behind the mouth and is
the passage to the stomach and the lungs.
 Larynx - It is present at the top of trachea and
contains vocal cords. It is also known as the
voice box.
 Trachea (windpipe) - It is a tube like structure
that helps in passage of air from larynx to the
bronchi.
The Lower Respiratory Tract
 Bronchi (bronchioles) - These are the
branches of the bronchi that conduct air
into the lungs.
 Alveoli (air sacs) - The sacs in the lungs
where gas exchange occurs.
 Lungs - The two inverted-cone shaped
organs present in the chest of human
beings.
How do you breathe?
 The diaphragm is a sheet of muscle under
the lungs which controls breathing.
 When the diaphragm contracts, the lungs
expand and air flows into the lungs.
 When the diaphragm relaxes, the lungs
relax and air is forced out of the lungs
Inhalation and Exhalation
How does the Respiratory System
work?
 When you breathe in, air enters through
the nose or mouth and goes down the
trachea.
 At the end of the trachea are 2 branches
called bronchi, which carry air into each
lung.
 Inside the lungs the air passes from the
bronchi to the bronchioles and then to air
sacs. (Alveoli)
 Each alveolus is surrounded by capillaries.
These are very small blood vessels.
How does the Respiratory
System work? Cont’d
 The walls of the air sacs and capillaries
are very thin and they are close together.
 Oxygen passes through the walls to the
blood in the capillaries and carbon dioxide
passes to the air sacs.
 When you breath out carbon dioxide is
removed from the body.
Gas exchange
 We need to get oxygen from the air into
the blood, and we need to remove waste
carbon dioxide from the blood into the air.
 Moving gases like this is called gas
exchange. The alveoli are adapted to
make gas exchange in lungs happen
easily and efficiently.
Here are some features of the alveoli that allow
this:
• They give the lungs a really big surface area
• They have moist, thin walls (just one cell thick)
• They have a lot of tiny blood vessels called capillaries.
The gases move by diffusion from where they have a
high concentration to where they have a low
concentration:
Oxygen diffuses from the air in the alveoli into the blood.
Carbon dioxide diffuses from the blood into the air in the
alveoli.
Some water vapour is also lost from the surface of the
alveoli into the lungs - we can see this condensing when
we breathe out on cold days.
The effects of Physical Activity on
the Respiratory System.
 Increasing the amount of air taken in with
each breath.
 Reducing the rate of breathing
 Reducing the time it takes to recover your
normal breathing rate after strenuous
exercise.
 Strengthening the muscles that are
involved in the breathing process.