Gas Exchange
Rebekah Kim
Pranathi Rao
AP Biology
Period 0-1
Well...
did you think that gas exchange involved
burping and farting?
In case you didn't know
what farting sounds likes...
• http://www.youtube.com/watch?v=ZoDnu0i
xI-U
What is gas exchange?
That's what we thought too... BUT gas exchange
is ACTUALLY the uptake of molecular oxygen
from the environment and the discharge of
carbon dioxide to the environment.
Evolutionary Aspect
•
•
When earth was first created oxygen didn't
exist. In fact, oxygen came to existence 2.7
billion years ago. Therefore, gas exchange
emerged with the arrival of oxygen.
Since there was a scarcity of oxygen, natural
selection favored organisms which were able
to utilize the oxygen the most efficiently.
Evolutionary Aspect
•
•
Primitive invertebrates such as sponges,
cnidarians, flatworms, and roundworms
exchange gases with diffusion.
Segmented worms are too large to be
sustained by diffusion alone.
o
Uses their skin as an initial gas exchange surface, but
then uses blood to deliver the gases to and from their
body cells.
Why is gas exchange
necessary?
• http://www.youtube.com/watch?v=1Fh_ZIy
oUhU
Gas exchange is important
because...
• It allows for the transfer of oxygen from the
surroundings to individual cells in the body
needed for respiration.
o
•
•
This process produces energy that is essential for the
organism to survive.
If carbon dioxide wasn't removed from the
body by gas change, it would be harmful.
Ultimately, without the gas exchange we
would die from lack of oxygen.
Major Structures...
Respiratory
Surface
Diffusion...
•
Gas exchange is fast when the area of
diffusion is large and the path for diffusion is
short so the structure of a respiratory surface
is usually large and thin.
Major structures...
Larynx
Major Structures...
Trachea
Major Structures...
Lungs
Major Structures...
Alveoli
Gills
Major Structures...
The effect of having gills...
• http://www.youtube.com/watch?v=H4BNbH
BcnDI
The interdependence of the
gas exchange...
• Gas exchange depends on the functioning of
•
•
the respiratory as well as the circulatory
system.
The respiratory system helps exchange the
intake of oxygen with carbon dioxide
The circulatory system allows the
oxygenated blood to travel throughout the
body.
Major Structures...
Heart
Breathing Mechanisms...
How a mammal breathes:
•
•
Mammals employ negative pressure breathing.
Mammals lower air pressure in their lung below that
of the air outside their body.
How an amphibian breathes:
•
•
An amphibian employs positive pressure breathing.
The air goes through the nostrils and is forced down
the trachea and is released by the lungs and muscular
body wall.
Diseases/Disorders
•
Asthma
o
o
o
o
A chronic lung disease that inflames and narrows the
airways.
 The airways become swollen and the muscles
tighten, which triggers the symptoms.
It causes recurring periods of wheezing, chest
tightness, shortness of breath, and coughing.
Asthma can start at any age, but usually develop
when people are young.
Asthma is caused by genetics, allergies, respiratory
infections, and the environment.
Diseases/Disorders
•
Emphysema
o
o
o
A lung disease that makes it hard to breathe.
It occurs when the air sacs in the lungs are gradually
destroyed, which leaves the person more short of
breath.
As it worsens, emphysema reduces the surface area
of the lungs and the amount of oxygen that reaches
the bloodstream.
 Smoking is the major cause of emphysema.
Diseases/Disorders
•
Pneumonia
o
o
A common lung infection caused by bacteria, a virus
or fungi.
The alveolar spaces fill with mucus, inflammatory
cells, and fibrin.
 Causes: viruses, adenoviruses, rhinovirus,
influenza virus (flu), respiratory syncytial virus,
and parainfluenza virus.
 Symptoms: fever, chills, cough, chest pain, rapid
breathing, nasal congestion, wheezing, etc.
Diseases/ Disorders
•
Hypoventilation
This is the result of an insufficient exchange of gases.
o This leads to increased levels of carbon dioxide in
the blood.
o It can be caused by natural barriers in the airway as
well as through resistances to adequate airflow.
o Symptoms can include: headaches, heart problems,
stomach problems and faintness.
 It can also lead to poor sleep due to constant
awakeness and result in daytime sleepiness.
o
Diseases/Disorders
•
Hyperventilation
o
o
o
A respiratory disorder, which is associated with
rapid or deep breathing that can occur with anxiety
or panic.
This causes an excessive release of carbon dioxide.
It reduces the CO2 concentration of blood to below
its normal level and raises the blood's pH level.
 Common causes: stress and anxiety
 Symptoms: numbness or tingling in the hands,
feet and lips; lightheadedness, dizziness,
headache, chest pain, spasm, slurred speech,
nervous laughter, and sometimes fainting.
So...
What is the difference between HYPERventilation
and HYPOventilation?
- HYPERventilation is a state in which there is excessive
breathing that causes CO2 blood levels to become too low.
- HYPOventilation is a result of inadequate gas exchange
where not enough oxygen is taken in and not enough
carbon dioxide is exhaled, leading to CO2 buildup in the
blood.
TO: Mrs. Said
•
(from: the class)
Hyperventilation is a respiratory disorder
caused by stress and this project has given
all of us so much stress so please Mrs. Said
for the sake of our lungs please give us
an A.
Gas Exchange Questions
1.
The rate of diffusion is _________________ proportional to the surface
area of the respiratory surface and ___________________ proportional to
the square of the distance.
a. directly, directly
b. inversely, directly
c. directly, inversely
d. inversely, inversely
e. None of the above
More Gas Exchange
Questions
2. How much oxygen is found in the air?
a. 15%
b. 21%
c. 47%
d. 65%
e. 74%
Gas Exchange FRQ
Describe how the circulatory and the
respiratory systems allow gas exchange to
occur.
WebSites
•
•
•
•
http://www.scientificamerican.com/article.c
fm?id=origin-of-oxygen-in-atmosphere
http://www.ncbi.nlm.nih.gov/pmc/articles/PM
C1570919/
http://www.enotes.com/gas-exchangereference/gas-exchange
http://cwx.prenhall.com/bookbind/pubboo
ks/martini10/chapter24/custom2/deluxecontent.html
WebSites continued...
•
•
•
http://www.cliffsnotes.com/study_guide/M
echanisms-for-Gas-Exchange.topicArticleId8741,articleId-8707.html
http://georgiahealth.edu/itss/edtoolbox/Ge
orgiaLabs/AcidBase/hyper_hypoventilate/H
yperHypoventilation.html
http://www.sleepassociation.org/index.php?
p=hypoventilation