Grade 9 Quarter 1

1. RESPIRATOR
Y VOLUMES
AND
CAPACITIES

2.  Air in the lungs is measured in
terms of lung volumes and lung
capacities.
a. Volume measures the amount
of air for one function (such as
inhalation or exhalation)
b. Capacity is any two or more
volumes (for example, how much
can be inhaled from the end of a
maximal exhalation).

3.  An average of 500 mL of air moves
in and out of the lungs during each
normal breath. This amount of air is
called tidal volume.
 But if a person forcibly inhales a
volume of air that is much higher
than the normal then he/she
acquires an inspiratory reserve
volume (IRV).

4.  The normal IRV ranges from 2100
ML to 3200 mL.
 In contrast, the expiratory
reserve volume (ERV) is the
amount of air that can be forcibly
exhaled after an expiration, is about
1200 mL.

5. Residual Volume is the amount of
air that remains inside the lungs after
ERV is exhaled. It cannot be
voluntarily released.
 Allows continuous gas exchange
and inflates the alveoli. The amount
of air does not reach the alveoli and
remains in the conducting
passageways is called dead-space
volume which is around 150 mL.

6. Functional volume, which is
approximately 350 mL reaches
the alveoli and contributes to
the exchange of gases.

7. Vital capacity, is the total amount
of exchangeable air and is usually
around 4800 mL. It is expressed as:
VC = TV + IRV + ERV

8. What is Spirometer?

9. A spirometer is an apparatus for
measuring the volume of air inspired
and expired by the lungs. A spirometer
measures ventilation, the movement of
air into and out of the lungs.
 Spirometry is a simple test used to
help diagnose and monitor certain lung
conditions by measuring how much air
you can breathe out in one forced
breath.

10. Conditions that can be picked up and
monitored using spirometry include:
Asthma – a long-term condition in which the
airways become periodically inflamed
(swollen) and narrowed.
Chronic Obstructive Pulmonary Disease
(COPD) – a group of lung conditions where the
airways become narrowed
Cystic fibrosis – a genetic condition in which
the lungs and digestive system become clogged
with thick, sticky mucus.
Pulmonary fibrosis – scarring of the lungs.

11. You'll be seated during the test and a
soft clip will be placed on your nose to
stop air escaping from it.
When you're ready for the test, you'll be
asked to:
1. Inhale fully, so your lungs are
completely filled with air.

12. WHAT HAPPENS DURING
SPIROMETRY TEST?

13. What happens during a spirometry
test?
2. Close your lips tightly around the mouthpiece.
3. Exhale as quickly and forcefully as you can,
making sure you empty your lungs fully.
 Spirometry will normally need to be repeated
at least 3 times to ensure a reliable result.
 These measurements will be compared with a
normal result for someone of your age, height
and sex, which will help show if your lungs
aren't working properly.

14. FOLLOW UP!
Q1: What is the difference
between IRV and ERV?
Q2: What is the importance
of spirometry?