2. Function of the Respiratory System
• To provide a constant supply of
oxygen (O2) to keep your body cells
functioning
• To remove carbon dioxide (CO2) from
the body cells
3. Structure of the Respiratory
System are the Organs
• Nose
• Mouth
• Nasal cavity
• Pharynx
• Epiglottis
• Larynx
• Trachea
• Bronchus (bronchi)
• Bronchioles
• Alveoli
• Pleura
• Diaphragm
Lungs
5. Mouth & Nose
• Brings air (O2) into the body
• Carbon Dioxide leaves the body through the
mouth and nose
• Nasal hairs in nostrils filter and trap dust.
• Air is not filtered as much when it enters in
through your mouth.
6. Nasal cavity
• Warms & moistens air
• Glands that produce sticky mucus line
the nasal cavity
– traps dust, pollen, and other materials that
were not trapped by nasal hairs
– cilia sweep mucus and trapped material to
the back of the throat where it can be
swallowed
7. Pharynx (Throat)
• Tube-like passageway used by food,
liquid, and air
• At the lower end of the pharynx is a flap
of tissue called the epiglottis
– covers the trachea during swallowing so
that food does not
enter the lungs
epiglottis
8. Larynx
• “Voice box”
• The airway to which
two pairs of
horizontal folds of
tissue, called vocal
cords, are attached
9. Trachea (Windpipe)
• Air-conducting tube
• Connects the larynx with the bronchi
• Lined with mucous membranes and
cilia
• Contains strong cartilage rings which
hold the trachea open. Without these
rings your trachea might close off and
air would not be able to get to and from
your lungs.
10. Bronchi
• Two short tubes that branch off the
lower end of the trachea
• Carry air into the lungs.
• Singular - bronchus
11. Bronchioles
• bronchi tubes split up, like tree
branches, and get smaller and smaller
inside your lungs.
• The tiny branches of air tubes in the
lungs are bronchioles
• Connect bronchi to alveoli
12. Alveoli
• Tiny, thin-walled, grapelike clusters at
the end of each bronchiole
• Surrounded by capillaries
• Where carbon dioxide and oxygen
exchange take place
• Singular - alveolus
16. Diaphragm
• Muscle wall between the chest and the
abdomen that the body uses for breathing
• Lungs expand and contract in response to
changes in pressure inside the chest cavity.
• The diaphragm flattens to cause the chest to
expand and air is pulled into the lungs.
• When the diaphragm relaxes, the chest
collapses and the air in the lungs is forced out.
19. Inhalation
• Breathing in
• Body gets oxygen from the air
• Rib muscles contract to pull ribs up and
out
• Diaphragm muscle contracts to pull down
the lungs
• Tissue expands to force (pull) in air.
20. Exhalation
• Breathing out
• Get rid of carbon dioxide
• Rib muscles relax
• Diaphragm muscle relaxes
• Tissue returns to resting position and
forces (pushes) air out
24. Relationship to Digestive System
• Cellular respiration requires glucose
and oxygen to release energy to the
body
• C6H12O6 + 6O2 à 6CO2 + 6 H2O + Energy
• Oxygen is provided by the respiratory
system
• Glucose is provided by the digestive system
• (glucose is made during photosynthesis)
25. Relationship to Nervous System
• The respiratory system is under control of
the involuntary and voluntary nervous
system.
—We don’t think about breathing.
—The autonomic nervous system controls
breathing in response to the amount of
carbon dioxide in the blood.
26. Relationship to Nervous System
• The respiratory system is under control of
the involuntary and voluntary nervous
system.
—We don’t think about breathing.
—The autonomic nervous system controls
breathing in response to the amount of
carbon dioxide in the blood.
27. Relationship to Nervous System
—Humans can decide to hold their breath.
—The respiratory system is then controlled
by the somatic nervous system.
—If you pass out from holding your breath,
your autonomic nervous system will take
over and return the blood gasses to
normal.
28. Respiratory Information
Each lung is about the size of a football.
The lungs fill the area from the collarbone to
the bottom of the ribs.
Lungs are the only organ in the body light
enough to float.
There are 300-500 million alveoli having a
total surface area or about 75 m2 in adults
(about the size of three living rooms).
29. Respiratory Information
• If all the capillaries that surround the
alveoli were unwound and laid end to end
they would extend about 620 miles.
• At rest, the body takes in and breathes out
about 10 liters of air each minute.
• The right lung is slightly larger than the
left.
• The highest recorded "sneeze speed" is
165 km per hour.
30. Respiratory Information
• The surface area of the lungs is roughly
the same size as a tennis court.
• We lose half a liter of water a day through
breathing. This is the water vapor we see
when we breathe onto glass.
• A person at rest usually breathes between
12 and 15 times a minute.
• The breathing rate is faster in children
and women than in men.
