Here are the answers to questions 1-4 on page 288: 1. What is the normal adult respiration rate at rest? Around 12 breaths per minute. 2. What is the normal tidal volume at rest? Around 0.5 L per breath. 3. What is the normal minute ventilation at rest? Around 7.5 L per minute. 4. During high intensity exercise, what can the respiration rate reach? It can reach 35-40 breaths per minute during high intensity exercise.

1. Chapter 12, part 1
Cardio-Respiratory System

2. Functions of the Respiratory
System
• Bring air from the atmosphere to the lungs
• Transfers oxygen into the blood
• Removes carbon dioxide from the blood
• Expels heat and water vapour in the air
breathed out
• Allows the vocal cords to create speech
as air is breathed out

3. Respiratory Anatomy
• The major organ is the lung
• Air from the atmosphere enters the body through
the mouth/nose, then passes through the
pharynx and larynx (voice box) before entering
the trachea (windpipe). This divides into 2
bronchi (one to each lung) and they further
subdivide into bronchioles. These empty the air
into the alveoli (air sacs) where gas exchange
with the blood occurs.

4. The lungs
Nasal cavity
Trachea
Bronchus Lungs
Alveoli
Bronchioles
Diaphragm

5. Left Lung - Bronchiole - Alveolus

6. Mechanics of Breathing
• Breathing in is technically called inspiration while
breathing out is called expiration
• Breathing is caused by changing the size of the
chest cavity
• It takes effort to enlarge the chest cavity. The
diaphragm contracts (pulling downward) and the
intercostal (between the ribs) muscles help pull
the ribcage outward.

7. Mechanics of Breathing Cont.
• With the chest cavity enlarged the air
pressure inside the lungs decrease and
causes air to be sucked in.
• Breathing out happens when the
diaphragm and intercostal muscles relax.
The chest cavity gets smaller increasing
the air pressure and forcing air out of the
lungs.

8. Intercostal Muscles Diagram
Internal Intercostal
Muscles
External Intercostal
Muscles
Diaphragm

9. Lung Volumes
• Each minute a person breathes, they
move approximately 9 Litres of air in and
out of their lungs.
• The amount of air a person can inhale and
hold or exhale varies according to: body
size, state of health and activity level.

10. Vital capacity readings
for adolescent male and
female students
Boys (litres) Girls (litres)
Ranking 12 years 15 years 12 years 15 years
Top 10% 3.65 5.5 3.6 4.25
Mid- 3.0 4.5 2.9 3.6
range
Lowest 2.15 3.15 2.05 2.6

11. Definitions
• Respiration rate – number of breaths per minute
• Tidal volume – the amount of air breathed in and
out normally
• Minute ventilation – the amount breathed in and
out in one minute (ventilation = tidal volume x
respiratory rate
• Vital Capacity – the maximum amount of air you
can breathe out after breathing in

12. • Oxygen uptake (VO2) – the amount of oxygen
used by the body in one minute
• Maximal oxygen uptake (VO2max) – the
maximum amount of oxygen your body can use
in one minute. This is the best indicator of how
aerobically fit someone is
• Residual volume – the amount left in the lungs
after breathing out all you can
• Inspiratory reserve capacity – the amount you
can breathe in after a normal breathe in
• Expiratory reserve capacity – the amount you
can breathe out after a normal breathe out

13. What Happens During Exercise?
- Breathing rate (or respiration) increases
- under normal conditions, adult respiration rate is about 12 breaths/min.
– under high intensity exercise conditions, this can reach 35–40 breaths/min.
- Tidal volume (TV) increases
– at rest this is around 0.5 L/min.
– under high intensity exercise conditions, this can reach around 4–5 L/min.
- Ventilation increases
- at rest this is approximately 7.5 L/min
- under high intensity exercise conditions, this can reach around 150 L/min
- Vital capacity (VC) remains the same
– this lung volume remains the same during one acute exercise session.
– it can be reduced by asthma and other respiratory problems such as the common
cold, bronchitis or emphysema.
- Oxygen uptake increases
– at rest the average amount of oxygen that an individual can take into the body is
about 3-4 mL/kg/min.
– under sub-maximal exercise conditions this can increase to around 30–50
mL/kg/min.

14. Complete Checkpoint
Questions 1-4 on page 288