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biology 0610printed 145 · PDF 145
328 pagesrevision 46933
printed 145 · PDF 145
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containing water and mucus.Cilia,tiny hair like projection in nose sweep the mucus
(which has bacteria trapped in it) and sweep it back up so that the lungs are not
blocked.
After the nose air passes to the trachea or windpipe. The trachea has a ring of
cartilage around it which prevents it from collapsing at times when air pressure inside
is lower than air pressure outside
Trachea goes into thorax(upper part of body from neck to the diaphragm).Trachea
divides in 2 in thorax. The 2 branches are known as bronchi.One bronchus goes to
the left lung and the other to the right lung.
Bronchus then divides further into bronchioles in the lungs
There are tiny air sacs at the end of each bronchiole which are known as Alveoli. This
is a gas exchange surface.
Inhale and exhaled air comparison
Component
Percentage in inhaled
air
Percentage in exhaled
air
Oxygen
21
16
Carbon Dioxide
0.04
4
Water Vapour
variable
Usually very high
Breathing Movements
There are several muscles involved to help you breath in and out.
One of them is intercostal muscles
The other is diaphragm which is a large sheet of muscle and elastic tissue which
stretches across your body underneath the lungs and heart.
Difference in the body while breathing in and out
Breathing in
Breathing Out
Diaphragm contracts
Diaphragm relaxes
Volume of thorax increases
Volume of thorax decreases