BREATHING IN HUMANS
VENTILATION
INHALING
EXHALING
Diaphragm contracts to become flatter and
pushes digestive organs down
External intercostal muscles contract to
raise ribs
Diaphragm relaxes and is pushed up by
displaced organs underneath
External intercostal muscles relax and ribs
fall
Volume of chest cavity decreases
Pressure in L{JNGS increases and rises "ABOVE ATMOSPHERIC pressure
Air moves out of the lungs
Volume of chest cavity increases
Pressure in CHEST CA'VITY drops
BELOW ATMOSPHERIC pressure
Air moves into lungs
MEASURING LUNG VOLUME
Tidal volume
Vital capacity
volume of air moved in and out with each
breath normally measured at rest e.g.
around 0.5 dm3
the maximum volume of air that can be
move by lungs in one breath by taking a
deep breath and expiring all the air possible
e.g. 2.5 - 5.0 dm3 according to height, age
sex and fitness levels
Residual volume
the air that remains in the airways and
alveoli even after forced expiration approx.
1.5dm3
Inspiratory volume
how much more air you can breathe in over
and above tidal volume
how much more air you can breathe out
over and above tidal volume
air in bronchioles, bronchi and trachea
where no gas exchange takes place
Expiratory volume
Dead space
BREATHING IN HUMANS
MEASURING LUNG VOLUME
Fill the gaps
…………….. volume
Vital ……………………
Residual …………………..
………………. …………………..
………………. …………………..
Dead space
volume of air moved in and out with each
breath normally measured at rest e.g.
around 0.5 dm3
the maximum volume of air that can be
move by lungs in one breath by taking a
deep breath and expiring all the air possible
e.g. 2.5 - 5.0 dm3 according to height, age
sex and fitness levels
the air that remains in the airways and
alveoli even after forced expiration approx.
1.5dm3
how much more air you can breathe in over
and above tidal volume
how much more air you can breathe out
over and above tidal volume
air in bronchioles, bronchi and trachea
where no gas exchange takes place
VENTILATION re-sort the sequence in each column. The first event is correct.
INHALING
EXHALING
Diaphragm contracts to become flatter and
pushes digestive organs down
Pressure in LUNGS increases and rises
ABOVE ATMOSPHERIC pressure
Pressure in CHEST CAVITY drops
BELOW ATMOSPHERIC pressure
Volume of chest cavity decreases
Volume of chest cavity increases
Air moves out of the lungs
Air moves into lungs
External intercostal muscles relax and ribs
fall
External intercostal muscles contract to
raise ribs
Diaphragm relaxes and is pushed up by
displaced organs underneath