CHAPTER 1 : RESPIRATION
1.1 : The Human Breathing
Mechanism
1.2 : Transport of Oxygen
1.3 : Cell Respiration
1.4 : Importance of a
Healthy
Respiratory
System
1.1 : Human Breathing Mechanism
Structure of the Human Respiratory System
1.1 : Human Breathing Mechanism
Structure of the Human Respiratory System
Bronchioles :
Nose :
• Fine air tubes;
• Always moist with
• Ends in cluster of
fine hairs to filter the
air sacs (alveoli)
air
Alveoli :
Trachea :
• Surrounded by
• Strong muscular
blood capillaries
tube; has rings of
cartilage
Bronchi :
• Each bronchus
branches into
bronchioles
1.1 : Human Breathing Mechanism
Structure of the Human Respiratory System
Rib muscles :
• Called intercostal
muscles – contract /
relax and caused
the ribs move
upwards /
downwards
• Causes thoracic
cavity (chest cavity)
to expand or
contract allowing
breathing in & out
Ribs :
• Works together with
breastbone
(sternum) to protect
the lungs
Diaphragms :
• Large sheet of
muscle that can
contract and or
relax
1.1 : Human Breathing Mechanism
Breathing and Respiration
Breathing :
• Mechanical process
which alternately
draws & expels air
into & out of the lungs
Respiration :
• Chemical process that
takes place in the
cells of the body
• Aka internal or cell
respiration
Normally we breathe
from 15 – 20 times
per minute
Rate of breathing
increases during
active work / exercise
1.1 : Human Breathing Mechanism
The Breathing Mechanism
Inhalation :
• Breathing in air
Exhalation :
• Breathing out air
Pathway of inhalation
:
• Nose – trachea –
bronchi –
bronchioles –
alveoli
Passing through the
nose, the air is :
• filtered;
• Warmed to body
temperature
• Moistened by mucus
1.1 : Human Breathing Mechanism
The Breathing Mechanism
Inhalation :
 External intercostal
muscles contract
 Ribs are raised &
the chest moves
forwards
 Diaphragm muscles
contract, is lowered
& flattened
 Thoracic cavity
expands
 Air pressure in the
thoracic cavity
decreases
 Air is rushed into the
lungs
1.1 : Human Breathing Mechanism
The Breathing Mechanism
Exhalation :
 External intercostal
muscles relax
 Ribs are lowered &
the chest moves
inwards
 Diaphragm muscles
relax & curves
upwards
 Thoracic cavity
becomes smaller
 Air is forced out
from the lungs.
1.1 : Human Breathing Mechanism
Model to show
the Action of
the Diaphragm
1.1 : Human Breathing Mechanism
Model to show the Action of the Diaphram
INHALATION
 When the sheet of
rubber (diaphragm) is
pulled down, the
volume in the bell jar
(thoracic cavity)
increases
 Air pressure in the bell
jar (thoracic cavity)
decreases
 Air from outside rushes
into the balloons
(lungs) via the Y-tube
(trachea & bronchi)
 Balloons expand as
filled with fresh air
EXHALATION
 When the sheet of
rubber (diaphragm) is
pushed upwards, the
volume in the bell jar
(thoracic cavity)
decreases
 Air pressure in the bell
jar (thoracic cavity) &
in the balloons (lungs)
increases
 Air is forced out
through the Y-tube
(bronchi & trachea)