The document discusses the mechanisms of respiration and breathing. It describes that respiration involves two main steps - breathing and gas exchange. Breathing has two phases, inhalation and exhalation. Inhalation occurs when the diaphragm contracts, decreasing air pressure and causing air to rush into the lungs. Exhalation occurs when the diaphragm relaxes, increasing air pressure and pushing air out of the lungs. Gas exchange happens via diffusion in the alveoli, where oxygen moves into the blood and carbon dioxide moves out.

1. Breathing Mechanisms

2. explain the mechanism
of respiration.
1
At the end
of the
lesson, you
should be
able to:

3. • Respiration that involves gas exchange in the respiratory
system can be divided two major steps:
Respiration
Breathing
● Inhalation
● Exhalation
Gas Exchange
● In the lungs

4. Inhalation
• It is when the
diaphragm contracts
and induces the
decrease in air
pressure within the
lungs.
Two Phases of Breathing
Breathing process

5. Inhalation
• This difference in
air pressure
between the lungs
and the atmosphere
causes air to rush
into the lungs.
Two Phases of Breathing
Breathing process

6. Exhalation
• As a person breathes
out, the diaphragm
relaxes which decreases
the size of the chest
leading to the increase
in air pressure in the
lungs.
Two Phases of Breathing
Breathing process

7. Exhalation
• The higher pressure in
the lungs compared to
the atmosphere pushes
air to rush out of the
lungs.
Two Phases of Breathing
Breathing process

8. • The site of gas exchange
between air and the
blood is the alveoli.
• The mechanism behind
gas exchange is
diffusion
Gas Exchange
Site of gas exchange

9. • Lung capacity is the volume of air associated with the
inhalation and exhalation process.
• The adult human male has a total lung capacity of 6 liters of
air.
• The average human respiratory rate is 30–60 breaths per
minute at birth, decreasing to 12–20 breaths per minute in
adults.
Lung Capacity

10. In measuring the lung capacity, the following variables are
considered:
• Vital capacity (VC) is the volume of air exhaled out after
the deepest inhalation.
• Residual volume (RV) is the volume of air remaining in the
lungs after a maximal exhalation.
Lung Capacity

11. In measuring the lung capacity, the following variables are
considered:
• Total lung capacity (TLC) is the volume in the lungs at
maximal inflation, the sum of VC and RV.
• Tidal volume is the volume of air moved into or out of the
lungs.
Lung Capacity

12. Respiration has two major steps: breathing and gas
exchange.
1
2
Breathing has two phases: inhalation and
exhalation.
2
Gas exchange is governed by diffusion. Diffusion is
the movement of gases from a higher concentration
to a lower concentration.
3

13. Inhalation
___ alveoli
___ trachea
___ larynx
___ pharynx
___ bronchi
___ bronchioles
___ nostrils
Trace the pathway of air during inhalation and
exhalation where 1 is the entry and 7 is the exit.
Exhalation
___ alveoli
___ trachea
___ larynx
___ pharynx
___ bronchi
___ bronchioles
___ nostrils

14. Oxygen is vital for our
cells to function. It is one
of the main reasons why
we breathe. What will
happen if our breathing
was cut?