Transcript Respiratory System Red

RESPIRATORY SYSTEM
by Harry Carter, Ian Cooper,
Kazuki Moriguchi, and John Su
The Structure of the Respiratory System
The respiratory system consists of the mouth, epiglottis, larynx
and trachea leading to the lungs.
The lungs contain the bronchial tubes, the alveoli, bronchioles,
and capillaries.
The diaphragm lies beneath the
lungs.
The Diaphragm
The diaphragm is an involuntary muscle directly below the
lungs. It contracts and pulls down, essentially creating a
vacuum inside your chest. This vacuum is quickly filled with
your lungs which themselves are filled with air. This is how air
gets into our lungs to keep us alive.
The Bronchi and Bronchioles
After air leaves the trachea it goes down through two branches
called bronchi, which goes deeper into the lungs and keeps
splitting like a tree. This continues and at this point they are
smaller branches called bronchioles, which contain alveoli.
The Alveoli
The cup-shaped alveoli (where the most amount of gas
exchange takes place), clustered in alveolar sacs, are located
at the end of the bronchioles. They offer a tremendous surface
area for oxygen and carbon dioxide to be exchanged.
Fun Fact: If all the alveolar sacs were stretched out in one
layer, they would cover the floor of a racquetball court (800 sq
ft).
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From Mouth to Lungs: The movement
of air.
• When we breathe in from either our mouth or nose, the air
travels into the pharynx (located at back of nose and mouth)
• The pharynx leads to two passageways, one for food and the
other, the trachea (covered by the epiglottis), for air.
• The trachea is lined with cilia that sweep fluids and foreign
particles out of the airways and away from lungs.
• Path of air: nasal cavities (or oral cavity) → pharynx →
trachea → primary bronchi (right & left) → secondary bronchi
→ tertiary bronchi → bronchioles → alveoli (site of gas
exchange)
Gas Exchange
The exchange of gases (O2 & CO2) between the alveoli & the blood occurs by simple
diffusion: O2 diffusing from the alveoli into the blood & CO2 from the blood into the alveoli.
Diffusion requires a concentration gradient. So, the concentration (or pressure) of O 2 in
the alveoli must be kept at a higher level than in the blood & the concentration (or
pressure) of CO2 in the alveoli must be kept at a lower lever than in the blood. We do this,
of course, by breathing - continuously bringing fresh air (with lots of O2 & little CO2) into
the lungs & the alveoli.
Breathing Video
Reference
Izenberg, Neil. Lungs and Respiratory System. Teens Health, n.d. Web. 23 Oct.
2011. <http://kidshealth.org/teen/kh_misc/about.html>.
"Respiration." Human Physiology. Eastern Kentucky University, n.d. Web. 23 Oct.
2011. <http://people.eku.edu/ritchisong/301notes6.htm>.
Starr, Cecie, and Ralph Taggart. BIOLOGY The Unity and Diversity of Life.
Pacific Grove: Brooks/Cole, 2001. Print.
"The Respiratory System." National Heart and Lung Institute. N.p., 1 June 2010.
Web. 23 Oct. 2011. <http://www.nhlbi.nih.gov/health/health-topics/topics/
hlw/system.html>.