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We take about 12-15 breaths per minute
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How many breaths per day?
How many breaths per lifetime?
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You take between 500 million to 750 million
breaths per lifetime
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We breath in a mixture of gases:
 78% Nitrogen
 21% Oxygen
 1% Argon
 0.04% Carbon Dioxide
 Other trace amounts of gases
But it’s the OXYGEN that our cells need!
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Think about why cells need oxygen and
discuss with you peers
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Cells use oxygen to obtain energy from food
through a process called aerobic cellular
respiration. Energy is released in a cell when
glucose (sugar molecule) reacts with oxygen
to form carbon dioxide and water.
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Aerobic Cellular Respiration: series of chemical
reactions that occur in the cell that provide energy
and consume oxygen.
C6H12O6 + 6O2
glucose + oxygen
6CO2 +
6H2O + energy
carbon dioxide +water +
energy
64% is released as thermal energy or energy
that helps animals maintain a constant body
temperature.
34% of the energy is stored in molecules called
ATP (adenosine triphosphate).
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Cells use ATP to power almost all of their
energy requiring processes:
 Growth
 Movement
 Building new molecules
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1 glucose yields, 36 molecules of ATP
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ATP is formed when energy from the
breakdown of glucose is used to add a
phosphate group to the ADP (adenosine
diphosphate) molecule in a process called
phosphorylation.
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In ‘simple’ organisms like jellyfish and
sponges, oxygen from the environment
diffuses directly into the cells through the cell
membrane and carbon dioxide diffuses out
into the environment
Gas Exchange: the processes whereby the body cells obtain
oxygen and get rid of carbon dioxide. (aka: diffusion of
gases)
Ventilation: the process in more complex organisms that ensures
a flow of oxygen-rich air to the lungs. (aka: breathing)
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In humans, fish and other large multi-cellular
organisms, gas exchange occurs in two
locations
 Lungs
 Body cells
The human respiratory system has four important
structural features that enable it to function
properly:
 A thin permeable respiratory membrane through
which diffusion can occur
 A large surface area for gas exchange
 A good supply of blood
 A breathing system for bringing oxygen-rich air to
the respiratory membrane
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The oil in the machine of our body
We make about 1 – 1.5 litres per day
When sick, consistency changes (or from
dehydration)
Allergies (and some infections) cause leakage
of mucus producing cells
Green colour can be from Neutrophils
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High Surface area
Air is 37oC and moist
Membrane is one cell thick
Passive Transport.
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Breathing is based on negative pressure
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Breathing is based on negative pressure
TOTAL LUNG CAPCITY:
TIDAL VOLUME:
The maximum volume of air that can be inhaled The volume of air inhaled or exhaled during a
during a single breath.
normal, involuntary breath. It's about 0.5L in
the average adult or 10% of the total lung
capacity.
INSPIRATORY RESERVE VOLUME:
EXPIRATORY RESERVE VOLUME:
The amount of additional air that can be
The volume of additional air that can be
inhaled after a normal inhalation.
exhaled after a normal exhalation.
RESIDUAL VOLUME:
The volume of air that remains in the lungs
after a forced exhalation. The residual volume
of air prevents the lungs from collapsing.
VITAL CAPACITY:
The maximum amount of air that can be
inhaled or exhaled. During periods of high
demand for oxygen the reserve volumes
decrease and tidal volume increases. The
maximum tidal volume is the vital capacity.
Vital capacity is about 4.4L to 4.8L in males
and 3.4L to 3.8L in females.
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Physical activity depends on the energy released during aerobic
cellular respiration which depends on the rate of oxygen delivary
a high maximum rate of oxygen usage indicates an efficient
respiratory system.
The rate of oxygen usage can be calculated using a spirometer.
VO2: It is an estimated or measured value representing the rate at which
oxygen is used in the body. It is measured in millilitres per kilogram
per minute (mL/kg/min)
VO2max: The maximum rate at which oxygen can be used in an
individual. It is the maximum amount of oxygen that an individual can
use during sustained, intense physical
activity. It is also
measured in mL/kg/min.
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EPO -- a hormone naturally produced by human
kidneys to stimulate red blood cell production