Unit Three
Respiratory System
Lisa Michelek
Human Respiration
• The transport system delivers nutrients obtained in the
digestive system to the body’s cells where
the nutrients combine with oxygen to release energy
needed to carry out the life processes of the organism.
• The life process responsible for releasing energy from
nutrients is respiration.
• In organisms, respiration involves an exchange of
gasses between the organism and its environment.
Human Respiration
• Respiration in humans is external, internal, and
cellular.
• External respiration occurs outside the cells and
involves the exchange of gases between the lungs
and the blood.
• Internal respiration takes place when gases are
exchanged between the blood and body’s cells.
• Cellular respiration is the energy releasing process
that takes place inside the cells.
Human Respiratory System
• The respiratory system
transports gases between
the external environment
and the internal surfaces
where gas exchange
occurs.
• In humans, air from the
environment moves
through a series of
passageways to the
lungs, where gas
exchange occurs.
Human Respiratory System
• Air first enters the respiratory system through the
nostrils and mouth.
• From the nostrils, air moves through hollow cavities,
called nasal passages, to the throat.
• The nasal passage is lined with mucous membranes
and hair-like structures called cilia.
• Air is filtered by cilia
where it is moistened &
warmed by the mucous
membranes before
it enters pharynx (back of throat).
Human Respiratory System
• The back of the throat is called
the pharynx.
• Located in the pharynx is the
glottis, which is the opening to
the windpipe.
• A flap of tissue called the
epiglottis covers the
glottis during swallowing.
• This prevents food from
entering the glottis and
trachea.
• If food enters the windpipe,
choking occurs.
Human Respiratory System
• The trachea (windpipe) transports
air to the bronchial tubes. It is kept
open by rings of cartilage.
• The trachea is lined with cilia that
beat constantly in one direction.
• The cilia move foreign material,
such as dust, pollen, and smoke, out
of the trachea and back to the nasal
passages.
• The cilia can be damaged by
smoking or air pollution.
Human Respiratory System
• At the upper end of the
trachea is the larynx (voice
box).
• The larynx contains the
vocal cords.
• Different sounds can be
produced in the larynx by
vibration of the cords.
• The pitch of a sound is
determined by the amount of
tension in the cords.
Human Respiratory System
• The trachea divides into two bronchial tubes called
bronchi.
• The bronchi branch into the lungs.
– Bronchial tubes are also lined with cilia.
• The bronchi further divide into smaller
tubes called bronchioles.
– The bronchioles are lined
with a mucous membrane.
• The bronchioles continue to
divide, ending in air sacs in
the lungs called the alveoli.
Human Respiratory System
• Gas exchange takes
place at the alveoli.
• The alveoli are also
called air sacs.
• They are moist and
thin, and are
surrounded by a
network of blood
capillaries.
Breathing
• Breathing is the movement of gases between
the atmosphere and the lungs.
• Air is moved into the lungs by inhalation and
moved out of the lungs by exhalation.
• The oxygen present in air is brought into the
body and carbon dioxide is given off into the air.
• Air moves into and out of the lungs because of
the differences in air pressure between the
chest cavity and the outside environment.
Breathing
• The lungs have no muscle tissue to help in
inhalation or exhalation.
• Air enters and leaves the lungs because of air
pressure changes in the chest cavity.
• The pressure
changes are
caused by the
contraction and
relaxation of the
diaphragm and
rib muscles during
inhalation and exhalation.
Breathing
• The diaphragm is a dome-shaped muscle located at the
bottom of the chest cavity.
• When you inhale, the diaphragm moves down and the rib
muscles move upward and outward.
– This movement enlarges your chest cavity, and air is forced into your
lungs.
• When you exhale,
the diaphragm moves
up to its original curved
position and the ribs
move in, making your
chest cavity smaller
and forcing air out of
the lungs.
Breathing Rate
• Breathing rate is affected by foreign particles
from smoking or air pollution, and the oxygen
(O2), carbon monoxide (CO), and carbon
dioxide (CO2) levels in the blood.
• The most important factor in controlling
breathing rate is the concentration of carbon
dioxide (CO2) in the blood.
• An increase in blood CO2 concentration
increases breathing rate.
• When the blood CO2 level decreases, breathing
rate decreases.
Cellular Respiration
• Cellular respiration is the energy-releasing process
that takes place inside living cells and involves the
exchange of gases between the blood and tissue
fluid and the cells.
• During cellular respiration,
oxygen combines
chemically with sugar
(glucose) to release energy
(ATP – adenosine triphosphate).
• Molecules of carbon dioxide
and water are waste
products of this process.
Aerobic Cellular Respiration
• In aerobic respiration,
oxygen is required.
• Glucose is broken down
completely to carbon
dioxide and water.
• The chemical energy of
the glucose molecule is
released and used to
make ATP.
Anaerobic Cellular
Respiration
• In anaerobic respiration, or
fermentation, oxygen is not required.
• Glucose is partially broken down into
lactic acid or alcohol and carbon
dioxide, by yeasts and bacteria.
• During prolonged exercise, muscle
cells are using oxygen faster than the
circulatory system can supply it.
• In this case, lactic acid may build up in
the muscle tissue and is associated
with muscle fatigue.
Respiratory System
Disorders
• Bronchitis
– An inflammation of the lining of
the bronchial tubes.
– The bronchioles secrete too
much mucus and become
small and irritated.
– Respiratory cilia cannot clear
the passages of the mucus
and particles that clog them.
– Affected persons are short of
breath and often cough up
mucus.
Respiratory System Disorders
• Asthma may be caused by:
• Allergens: House dust, dust mites, mold spores, pollen and animal dander
• Bacterial and Viral Infections: The common cold, influenza, sinusitis and
bronchitis
• Irritants: Air pollution, smoke, car fumes, perfume, paint odors and cold air
• Other: Weather changes, exercise, GE reflex, stress and emotions.
– During an asthma attack, the bronchial tubes narrow, which
prevents oxygen from entering the lungs.
The person may begin to have a dry
cough and chest tightness followed
by wheezing.
– Treatments include oral and inhaled
steroids, albuterol, and other medications
to prevent and control an asthma attack.
Respiratory System Disorders
• Emphysema
– A lung disease in which the alveoli
become large and break down.
– The lungs become less elastic and the
amount of air they can hold decreases.
– A person with emphysema experiences
shortness of breath with the slightest
activity.
– There is no cure for emphysema, but life
can be prolonged with proper treatment.
– Smoking is one cause of emphysema.
Respiratory System Disorders
• Lung Cancer
– Is an uncontrollable
growth of tumors in
the lungs.
– There is a proven
relationship between
lung cancer and
cigarette smoking.
Respiratory System Disorders
• Pneumonia
– Is an infection of the lungs
that is caused by a bacteria
or virus.
– The alveoli of the lungs fill
with fluid preventing proper
exchange of gases and
making breathing difficult.
– Some types of pneumonia
are treated with antibiotics.
Respiratory System Disorders
• Cystic Fibrosis
– Autosomal recessive disorder in which
defective gene/protein causes body to
produce unusually thick, sticky mucus
– Affects lungs most directly by clogging them
with mucus and resulting in bacterial
infections
– Also affects pancreas and it’s ability to
generate healthy enzymes to digest
food/nutrients
Overview of Respiratory System
• http://www.youtube.com/watch?v=zRv5tN
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• http://www.youtube.com/watch?v=AJpur6
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• http://www.youtube.com/watch?v=AyUtdqi
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• http://www.youtube.com/watch?v=00jbG_c
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