Transcript Preliminary PDHPE Core 2: The Body in Motion The Respiratory

Preliminary PDHPE Core 2:
The Body in Motion
The Respiratory System
• Respiratory System
- Structure and function
In order to function, all body cells
require oxygen which is delivered via
the blood. It is the role of the respiratory
system to supply oxygen to the blood
and to remove carbon dioxide and
waste products from the blood.
KEY TERMS:
Nose
Mouth
Pharynx
Lungs
Bronchus
Bronchiole
Larynx
Alveoli
Trachea
Structure
Function
Nose
The nose has a sticky surface and is covered with tiny
hairs called cilia which trap dust particles. These will be
moved towards the nose entrance to be sneezed out.
Mouth
Air moves into the mouth and the nose where it is
warmed, filtered and humidified.
Pharynx
The pharynx is the throat. It carries food as well as air.
Food continues down to the oesophagus. Air continues
down to the trachea. The epiglottis is a flap which stops
any food going down the trachea.
Larynx
The larynx is the voice box. It plays a large role in the
production of human speech. As the air expelled from
the lungs moves past, the vocal cords vibrate which
produces sound.
Trachea
The trachea is also called the windpipe. It is the major
airway to the lungs and is strengthened by cartilage rings.
It moves down into the chest where it divides into the two
bronchi.
Structure
Function
Lungs
There are two lungs which are cone-shaped and made
of elastic tissue. They are protected by the sternum, ribs
and spine. Along with the circulatory system, they play a
role in gas exchange and the transport system
Bronchus
Bronchiole
Alveoli
Two bronchus extend from the trachea. One bronchus
goes to each lung.
Once in the lungs, the bronchus divide into smaller
branches called bronchioles
Bronchioles continue to divide until they end in tiny sacs
called alveoli. They are elastic, thin-walled structures
which are covered densely in capillaries containing
blood. They play a major role in gaseous exchange.
Respiration is the process by which the body takes in
oxygen and removes carbon dioxide. Respiration uses
oxygen as a vital ingredient to free energy from food and
can be characterised by the following equation:
Glucose
(from food)
Oxygen (O2
breathed in)
Carbon
Dioxide (CO2
Breathed out)
Energy
Water
When humans breathe in (inhale), oxygen enters the respiratory system
through the mouth and the nose. The inhaled breath then passes through
the larynx (where speech sounds are produced) and the trachea, which is
the main tube entering the chest cavity.
In the chest cavity , the trachea splits into two smaller tubes called the
bronchi. Each bronchus then divides again forming the bronchial tubes.
The bronchial tubes further divide into many smaller tubes (bronchioles) ,
which connect to tiny air sacs called alveoli.
There are over 600 million of these
sponge like alveoli in a healthy human
lung. Oxygen inhaled into the lung
passes through the thin wall of the
alveoli and into the blood stream. At
the same time, poisonous carbon
dioxide passes back into the lung
through the wall of the alveoli.
Respiratory System
- Lung Function (inspiration, expiration)
Inspiration is breathing in. The diaphragm contracts, the ribs
move up and out a little which enlarges the chest cavity.
Because the chest is bigger, the pressure within the lungs
decreases. The air moves from an area of high pressure to
low pressure so the air is drawn into the lungs.
Expiration is breathing out. The diaphragm and ribs return to
their at-rest state which decreases the size of the chest
cavity. Thus the pressure inside the lungs is now high, so air is
forced out of the lungs.
‘Control of the breathing action is done by the muscular
diaphragm, which lies across the bottom of the chest cavity. The
diaphragm’s job is to help pump the carbon dioxide out of the
lungs and create a space to allow oxygen to flow into the lungs.
The ability to make use of atmospheric oxygen and remove
poisonous carbon dioxide from the body is one that not only keeps
human beings alive, but it can have a significant impact on the
body’s ability to move efficiently.’
Question: What impact does respiratory efficiency have upon
athletic performance?
Respiratory System
- Exchange of gases (internal, external)
‘Gas exchange occurs between the alveoli of the lungs and the
blood in the capillaries. As mentioned before, a substance moves
from an area of high concentration to an area of low
concentration.
The alveoli in the lungs have a high level of oxygen whilst the blood
in the capillaries have a low level of oxygen. Thus the oxygen in the
alveoli moves across into the blood in the capillaries. It is then
delivered back to the heart to undergo systemic circulation.
The blood in the capillaries has a high level of carbon dioxide whilst
there is a low level of carbon dioxide in the alveoli. Thus the carbon
dioxide in the blood moves across into the alveoli. It is then moved
back through the respiratory system to be exhaled.’
Lung function
Respiration is the exchange of gases between the cells, blood and
atmosphere. It involves four processes:
• pulmonary ventilation (breathing)—movement of air from the atmosphere
into the alveoli
• pulmonary diffusion—exchange of oxygen and carbon dioxide between
the lungs and the blood
• transport of respiratory gases—transportation of oxygen and carbon
dioxide between the lungs and the tissue cells of the body via the blood
• internal respiration—exchange of gases between the blood capillaries
and the tissue cells.
practical application
Heart rate test
As a class, participate in approximately 15 minutes of continuous aerobic
exercise, such as bicycle riding, jogging or swimming.
Tasks
1 Describe the changes in heart rate and respiratory rate that you observed from
the start of the activity until you reached a comfortable pace.
2 Compare how you felt just after starting the activity with how you felt after 10
minutes.
3 Explain what happened to your heart rate and respiration rate when you
sprinted or went up a hill.
4 Explain how you felt immediately after ceasing activity.
5 Calculate how long it took for your heart rate and respiration rate to return to
normal.