1. Human Respiration:
Ventilation
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2. Human Respiration
 Involves the process of:
a) cellular respiration:
Glucose + O2  H2O + CO2 + 36 ATP’s
b) gas exchange:
exchange of gases between the internal
and external environment with the use of
lungs
c. ventilation - breathing
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3. Ventilation System
why do we need it!?
 adequate lung ventilation is essential to
gas exchange
 ventilation provides a continual supply of
fresh air to the lungs needed to
maintain a large concentration gradient
for gas exchange >> surface of the
alveoli
 O2 must be delivered regularly
 CO2 must be quickly eliminated
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4. (I) Human Respiratory System
 Composed of a network of
passageways which permits
air to flow from the external
environment and into the
lungs
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5. The Upper Respiratory Tract
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6. Nasal Cavity
 The nose
 Lined with a ciliated
mucus membrane
 The cilia and mucus:
1. Filters air
2. Warms air
3. Moistens air
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7. Pharynx
 Known as the
throat region
 It is an area
in which both
air and food
pass through
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8. Larynx
 Humans
 use the larynx as a
voice box
 contains vocal cords
that vibrate and
produce sound as air
passes through
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9. Epiglottis
A cartilaginous
flap
 It “covers” the
trachea when
swallowing food
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10. Trachea
 Known as the windpipe
 Kept open by rings of
cartilage
 Lined with a ciliated
mucus membrane
 One cigarette
paralyzes the cilia for
20 minutes
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11. Lung
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12. Bronchi
 Bronchus = singular
 Trachea divides into two major
divisions known as bronchi
 The bronchi contain cartilage
rings as well
 The bronchi subdivide many times
forming smaller tubules known as
bronchioles
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13. Bronchioles
 Lack cartilage
rings
 Tiny bronchioles
subdivide and
terminate (end)
with structures
known as alveoli
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14. Alveoli
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15. Alveoli
 Are thin: single layer of cells – easy
diffusion
 Moist: helps gases to dissolve before
passing thru membranes/
 Alveoli increase surface area for gas
exchange
 Rich in blood vessels: O2 diffuses into
the blood from the alveoli and CO2
and water diffuse out of the blood
and into the alveoli
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16. (II) Breathing Process
 Inhaling – Inspiration
 Exhaling – Expiration
 Lungs are highly elastic (stretchable)
 Thoracic Cavity is sealed
 Atmospheric Pressure Constant
 Atmospheric Pressure forces air into the lungs:
 Volume Inc. / Pressure Dec. = Inhale
 Volume Dec. / Pressure Inc = Exhale
4 sets of MUSCLES that control breathing include:
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17. Diaphragm and Abdominal
Muscles
 Diaphragm contracts –
flattens dome – Inhale
 Abdominal muscles relax
 Diaphragm relaxes –
abdominal muscles
contract - Exhale
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18. Intercostal Muscles
 External Intercostals –
 Attached to rib cage
 Contracts to move rib cage up and out
 Inhale
 Internal Intercostal
 Attached to rib cage
 Contracts to move rib cage down and in
 Exhale
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20. II – Breathing Process
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21. III – Gas Exchange
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22. (III) Gas Exchange
• High Concentration gradient
needed.
• In the blood, hemoglobin binds
with oxygen from the alveoli to
form oxyhemoglobin (HbO2)
• Carbon dioxide is carried primarily
in the plasma of the blood in the
form of bicarbonate ions (HCO3)
Lung Attack – Gas Exchange
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23. THE END
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