Download THE RESPIRATORY SYSTEM

THE RESPIRATORY
SYSTEM
THE VARIOUS PARTS OF THE
RESPIRATORY SYSTEM ARE:•TRACHEA
•EPIGLOTTIS
•LARYNX
•BRONCHUS
•BRONCHIOLES
•ALVEOLI
•DIAPHRAGM
The air passes into the lungs down a tube
called the TRACHEA. This is made up of rings
of cartilage.
There are plates of cartilage at the top of the
TRACHEA which widen at the point commonly
called the “Adam’s Apple”.
This is actually the LARYNX or “Voice Box”.
This is protected by a flap of skin called the
EPIGLOTTIS which closes when we swallow in
order to prevent food from going down the
TRACHEA.
Occasionally this doesn’t happen and we have
all experienced feeling “choking” when food
goes down the wrong way.
At the bottom of the TRACHEA are 2
branches called the BRONCHI, through which
air passes into either lung.
Smaller and smaller branches, called
BRONCHIOLES, extend out from the
BRONCHI and at the very ends of these they
form tiny sacs called ALVEOLI.
ALVEOLI
It is these that give the lungs their spongy
texture.
The linings of the ALVEOLI are very thin and
only work well when they are moist and clean.
When air is breathed in through the nose, it is:
1. FILTERED by the hairs at the entrance to
the nose and by mucus.
2.WARMED by blood vessels passing close to
the lining of the nose.
3.MOISTENED by water vapour.
Summary of the various parts of the
RESPIRATORY SYSTEM.
BREATHING IN
When we breathe in, the cycle starts with the
ribs lifting upwards and outwards.
This is caused by the contraction of the
intercostal muscles which are situated
between the ribs.
There is also movement in the body as the
DIAPHRAGM contracts, changing from a
dome shape to a flatter sheet.
BREATHING OUT
It relaxes when we breathe out, moving
upwards back to a dome shape.
SUMMARY
GASEOUS EXCHANGE
The ALVEOLI are in very close contact with
the blood capillaries, which contain red blood
cells and Haemoglobin
We have already seen that Haemoglobin
carries oxygen and at this point in the
CIRCULATORY SYSTEM it attracts the
oxygen in the ALVEOLI.
Whilst the oxygen is taken in, carbon dioxide
is given out, into the Alveoli and is then
breathed out.
So the RESPIRATORY SYSTEM has 2 main
jobs:
1. To get oxygen into the body
2.To get carbon dioxide out of the body.
WHAT WE BREATHE
As well as breathing in oxygen, we also breathe
out a lot of oxygen.
This is most important when we give mouth to
mouth resuscitation.
1. The air we INHALE contains 20% oxygen and
0.4% carbon dioxide.
2. The air we EXHALE contains 16% oxygen
and 4% carbon dioxide.
This is why we can give the “kiss of life”
BREATHING DEFINITIONS
1. TIDAL VOLUME- The amount of air inspired
and expired with each normal breath at rest
or during exercise.
2.VITAL CAPACITY- The largest amount of air
that can be made to pass into and out of the
lungs by the most forceful inspiration and
expiration.
3. OXYGEN DEBT- You will develop oxygen
debt after about 5 minutes or more of
constant exercise. This is the point when the
exercise becomes ANAEROBIC (without the
use of oxygen) and which has to be paid back
later- hence OXYGEN DEBT. If the exercise
is just AEROBIC (with oxygen) there will be no
oxygen debt.
REVISION