Download THE RESPIRATORY SYSTEM

THE GAS EXCHANGE
SYSTEM
THE VARIOUS PARTS OF THE
RESPIRATORY SYSTEM ARE:•TRACHEA
•EPIGLOTTIS
•LARYNX
•BRONCHUS
•BRONCHIOLES
•ALVEOLI
•DIAPHRAGM
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.
Trachea
Bronchus
Bronchioles
Alveolus
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.
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
The diaphragm relaxes when we breathe out,
moving upwards back to a dome shape.
SUMMARY OF BREATHING - VENTILATION
GASEOUS EXCHANGE
The ALVEOLI are in very close contact with
the blood capillaries, which contain red blood
cells and haemoglobin
Diffusion occurs through the squamous
epithelial cells of the alveoli
Haemoglobin in the red blood cells carries
oxygen and at this point in the CIRCULATORY
SYSTEM it picks up oxygen from the
ALVEOLI. It drops off carbon dioxide.
So the RESPIRATORY SYSTEM has 2 main
jobs:
1. To get oxygen into the body
2.To get carbon dioxide out of the body.
AIR COMPOSITION
- 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.
AIR COMPOSITION
This is why we can give the “kiss of life”
OXYGEN DEBT- You will develop oxygen debt
after intense physical exercise.
This is the point when the exercise becomes
ANAEROBIC (without the use of oxygen) and
which has to be paid back later- OXYGEN
DEBT.
The oxygen debt is the volume of oxygen
needed to completely oxidise (break down) the
lactic acid that builds up in the body during
anaerobic respiration.
If the exercise is just AEROBIC (with oxygen)
there will be no oxygen debt.