Pulmonary Pulmonary ventilationventilation

What you need to do:What you need to do:• Count the number of breaths in a

minute• 1 minute countdown!• Make a note, this is your ventilation

rate

•Ventilation Rate (Breathing Rate): The number of breaths taken in one minute. (This is usually 12-20 breaths in a healthy adult).

•Pulmonary Ventilation: The total volume of air that is moved into the lungs during one minute.

Pulmonary ventilation = tidal volume x ventilation rate

(dm3 min-1) (dm3) (min-1)

• A peak flow meter and a clean mouthpiece can be used to measure your tidal volume (this is usually between 0.45 – 0.5dm3).

• Tidal Volume: The volume of air breathed in (or breathed out) during a single breath when at rest.

• Today, do the calculation using 0.5dm3

as the tidal volume (Note: this is the same as 500cm3).

Other pulmonary measurementsOther pulmonary measurements• A spirometer is a machine that measures volumes of

air inhaled and exhaled, it produces a trace of these volumes on graph paper or recorded on a computer.

• The vital capacity is the maximum amount or air that can be breathed out of your lungs in one breath, following the deepest intake of air possible. (It is not the total volume of the lungs, as there is always a small volume of air that cannot be expelled - called the residual volume).

• Note the significant difference between the tidal volume and the vital capacity on the following trace:

Breathing VolumesBreathing Volumes

EXPIRATORY RESERVE

INSPIRATORY RESERVE

TIDAL VOLUME

Total Lung

capacity

breathing in

breathing out

INSPIRATORY RESERVE = Extra air breathed in on a deep inspiration.

EXPIRATORY RESERVE = Extra air expired, ie. Over the normal 0.5dm3

0

0.5

3.0

2.5

2.0

1.5

1.0

0.5

1.0

1.5

2.0Residual volume

Vital

capacity

Read ‘Deep Read ‘Deep Breathing’ and Breathing’ and do Q4 p68-69 do Q4 p68-69

(Bill Indge (Bill Indge textbook).textbook).

Spirometer traceSpirometer trace

Trace from a spirometer, measuring a person’s Trace from a spirometer, measuring a person’s lung volumes before and during exercise.lung volumes before and during exercise.

a) 0.5 dm3

b) 12 breaths per minutec) 12 X 0.5 = 6 dm3min-1

d) 2.6 dm3

e) From 0.5 to 2.6 = 2.1increase, so 2.1 divided by 0.5 x 100 = 420%

increasef) 3.8dm3

g) 5 dm3

% increase = difference X 100 original value

Do the 4 summary Qs on p77.

Do the 3 summary Qs on p75.

End.

Control of breathingControl of breathing

• After exercise