Respiratory Function, Breathing,
Respiration
BI 233
Exercise 40
Introduction
• Pulmonary Ventilation is
the movement of air into
and out of the lungs and
the exchange of gases
across the respiratory
membrane
• The ventilation rate is the
number of breaths per
minute
• The pulmonary volume is
the amount of air inhaled
and exhaled with each
breath
Clinical Application
• Adequate pulmonary
ventilation is critical
• Reduction in pulmonary
ventilation can cause
increased C02 (hypercapnia)
producing acidosis
• Increased pulmonary
ventilation can lead to a
reduction in C02 (hypocapnia)
producing alkalosis.
• Changes in C02 concentrations
can alter breathing rates
Mechanics of Breathing
• Air moves from regions of higher
pressure to regions of lower
pressure.
• The lungs fill with air or deflate
due to changes in air pressure.
• During inspiration the diaphragm
contracts (with external
intercostals) increasing the
volume in thoracic cavity causing
a decrease in pressure in the
lungs which causes air to move
into the lungs.
• When the diaphragm relaxes the
size of thoracic cavity decreases
causing increase in pressure and
therefore causing expiration.
Measurement of Relaxed Breathing
Rate
• Calculate your lab partner’s
relaxed breathing rate
• Have partner read lab
exercise while you count
the number of breaths for 2
minutes.
• Divide by 2
• Record your results
• Do this again but have lab
partner do strenuous
exercise for 2 minutes and
then count the number of
breaths.
Pulmonary Volumes
• Pulmonary volumes are
the amount of air that
flows into or out of the
lungs during a particular
event.
• Tidal Volume(TV):
amount of air inhaled or
exhaled with each
breath under resting
conditions (300-500ml)
*The numbers given for volumes and
capacities are averages and vary
greatly between individuals
Pulmonary Volumes
• Inspiratory Reserve Volume
(IRV): Amount of air that
can be forcefully inhaled
after a normal tidal volume
inhalation (3100ml)
• Expiratory reserve volume
(ERV): amount of air that
can be forcefully exhaled
after a normal tidal volume
exhalation (1200ml)
• Residual Volume: Air left in
lungs (1000ml)
Capacities
• Lung capacities are
calculated by summation
of volumes
• Vital Capacity (VC):
Maximum amount of air
that can be exhaled after
a maximal inspiration
(4800ml)
• Calculate your volumes
and capacities including
the percent of expected
VC
Other Exercises
• Calculate your minute
ventilation
• Do flow and resistance
exercise and be able to
describe the
relationship between
these.
• Listen to your lab
partners respiratory
sounds with the
stethoscope
Cardiopulmonary Resuscitation
• CPR: typically used for
people suffering from a
heart attack (myocardial
infarct), drug overdoses,
drowning or trauma
and obstruction of
airways. Uses chest
compressions of 100
times per minute on the
body of the sternum.
Physiology of Exercise and
Pulmonary Health
Exercise 41
Exercise
• Aerobic exercises
increase heart rate and
breathing rates at
moderate levels for
extended periods of time.
• Anaerobic exercises
result in the consumption
of available oxygen faster
than it can be supplied to
the muscle tissue
Forced Expiratory Vital Capacity (FEV)
• Indications of health
can be roughly
correlated with the
amount of air expelled
from the lungs in 1
second.
• Expressed as a percent
when compared to a
person’s vital capacity.
• Should be approx 75%
Pulmonary Obstruction
• Occurs when the respiratory
passages are narrowed.
• Can be caused by excess
mucus (such as asthma) or
inflammation (such as
bronchitis.
• Most COPD is caused by
smoking.
• VC is normal but FEV1/VC%
is low.
• It takes longer to exhale
Pulmonary Restriction
• Occurs when the lungs
cannot fully inspire or
expire the full volume of air.
• Vital Capacity is reduced
• Caused by fibrosis of the
lungs (cystic fibrosis or from
asbestos) or adhesions of
the lung to the chest
(emphysema)
• FEV1/VC% is normal
Harvard Step Test
• Was developed to
determine a person’s
physical fitness.
• We do not have the steps
recommended in lab
manual but you can go
outside and walk up and
down stairs for 3-5 minutes.
• Subject then rests for 30
seconds
• Then partner takes pulses
every 30 seconds
• Calculate PFI:
Body Mass Index
• BMI is a general guide
to fitness
BMI= Weight in
pounds/(height in
inches)2 X 703
Or
BMI= Mass(kg)/ Height
(M)2
Waist/Hip Ratio
• WHR: According to the
American Heart
Association, people
who carry more weight
in their waist region are
more at risk for health
problems.
• WHR= Circumference of
waist/Circumference of
hips