THE PHYSIOLOGY of RESPIRATION
Efficient gas exchange can only occur if the alveoli
are regularly ______________________ with fresh air.
During ___________________, the thoracic cavity
_______________ because the diaphragm under the
lungs ___________________ and moves down.
As this space enlarges, air _________________.
During ______________________, the diaphragm
______________ and assumes its _________________ and
_______________ position and pushes up,
causing air to go ___________ of the lungs.
The __________________ separates the chest cavity from
the _____________________ cavity.
There are other muscles that can help you breathe
if you are short of breath and need to breathe more
deeply.
The movement of breathing is controlled by the
__________________ ______________________ in the brain.
Breathing is _______________________ and no matter how
long you try to hold your breath, your __________________
will soon take over.
The body will always try to continuously maintain
a steady state (__________________________).
The mechanism of breathing is controlled by the brain
detecting changes in the __________ of the
_____________.
As blood CO2 levels __________, pH falls (CO2 and water make
carbonic acid). Normal blood has a pH of about __________ but
if it gets lower than this (more acid), it indicates that blood
is _______________ in CO2.
The brain then makes you breathe more to
_______________ CO2 by diffusion in the lungs.