breathing - ambition, respect, care and...
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Breathing
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Aerobic respiration
Glucose is an important
substance that contains
stored chemical energy.
When glucose reacts
with oxygen, energy is
released. This is called
aerobic respiration.
All living organisms need a constant supply of energy. This
is because life processes, such as growing, use energy.
Most living things, including some micro-organisms, therefore
need a constant supply of oxygen to gain energy from food.
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The exchange of gases
Aerobic respiration is the process of releasing energy
through the oxidation of glucose molecules:
Oxygen is breathed
into the lungs and is
transported in blood.
oxygencarbon
dioxideglucose + + water ( energy)+
Carbon dioxide and water are formed
as waste products in cells. They can
be excreted when we breathe out.
The respiratory system carries out gas exchange. It is made
up of the lungs, intercostal muscles, diaphragm and airways.
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Parts of the respiratory system
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Label the respiratory system
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Why do we breathe?
Fish do this by keeping
a continuous stream of
oxygenated water
moving over their gills.
Animals need to ensure that a constant supply of oxygen is
able to diffuse into the blood and that any waste carbon
dioxide can diffuse out quickly.
In mammals and birds,
the process of ventilation
allows the stream of gases
to move to and from the
site of gas exchange.
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Model of ventilation
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The mechanism of ventilation
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Explain the terms
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The bell jar and the lung
In humans, the volume and pressure can be changed by the
movement of both the diaphragm and the ribcage.
lung
pleural membranes
The bell jar model of the lungs is limited because the
rubber sheet (representing the diaphragm) is the only way
to alter the volume and pressure of the chest cavity.
This occurs because of
the pleural fluid. This
fluid adheres the outer
walls of the lungs to the
chest cavity by water
cohesion, so that the
lungs expand with the
chest while breathing.
chest
cavity
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Gases moving in and out of the blood
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Spirometry
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Spirometric terms
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Exercise, respiration and ventilation
Energy is used up by the active
muscles during exercise.
The rate of respiration must
therefore increase to supply
enough energy to the muscles.
This means that more oxygen
must be breathed in and more
carbon dioxide breathed out.
the arteries supplying the muscles dilate?
During exercise, why does:
the heart rate increase
the rate and depth of breathing increase
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Running and breathing rates
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Carbon dioxide
One way the brain deals with
a build up of carbon dioxide
during exercise is by increasing
the rate of breathing.
The brain can detect the level of carbon dioxide in cells.
This increases the rate of gas
exchange and the removal of
carbon dioxide from the lungs.
When the level of carbon dioxide
increases during exercise, the brain
must coordinate ways to prevent the
levels reaching toxic levels.
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Keeping the airways clear
The walls of the trachea and bronchus contain goblet cells,
which secrete mucus made of mucin. This traps micro-
organisms and debris, helping to keep the airways clear.
The walls also contain
ciliated epithelial cells,
which are covered on
one surface with cilia.
These beat regularly to
move micro-organisms
and dust particles along
with the mucus.
The epithelial cells contain many mitochondria to provide
energy for the beating cilia.
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Why are respiratory diseases common?
Do you know anyone who has asthma?
Respiratory diseases are very common.
One reason for this is because the lungs are essentially a ‘dead end’. Any particles that are not removed by the mucus and cilia remain in the alveoli and damage the thin walls of these delicate structures.
This is evident from the lungs of a
smoker, which turn black from the
accumulation of trapped particles.
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Diseases have different causes
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Lung cancer and smoking
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Replacing body parts
Doctors and scientists have developed ways to replace body
parts when they stop functioning due to disease or trauma.
Sometimes, replacement
body parts can be
transplanted from a donor.
Lungs, hearts, kidneys,
livers and corneas are
examples of biological
replacement parts.
Mechanical replacement parts are also used. These might
be put inside the body, for example heart pacemakers.
Larger mechanical parts, such as lung machines and
artificial ventilators, must be used outside the body.
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External artificial aids
Artificial ventilators, and machines to maintain heart and kidney function, are used outside the body.
This can limit patient mobility:
Some are used intermittently,
such as dialysis machines.
Patients are able to move
around normally between
treatment sessions.
Others must be continuously
attached to the patient. For
example, artificial ventilators are
needed until patients regain the
ability to breathe for themselves.
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Asthma
Asthma is a chronic condition in which the airways narrow
and become inflamed, limiting airflow. It can be triggered by
allergens, dust, exercise, stress, infections etc.
Asthma causes difficulty
breathing, wheezing and
chest tightness, and can be
mild or life-threatening.
Inhalers are used treat asthma.
They contain bronchodilators,
such as salbutamol, to reduce
the narrowing of the airways.
Corticosteroids can also be
used to stop an asthma attack.
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Asthma attack
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Events during an asthma attack
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Glossary
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Multiple-choice quiz