Download SP_scuba_shortened_respiratory_lesson

What does this…
Diffusion
have to do with this?
Human Body
Respiratory
system:


Our lungs work by
diffusion!
Circulatory system
transports oxygen
and carbon dioxide
Examining your system..
Write your hypotheses....
 How do you think physical activity
will change your breathing rate
and the amount of time you can
hold your breath?
Who cares anyway?

What types of
professions or
people do you think
would have a
particular interest in
understanding
these body
systems?




Doctors
Athletes
Emergency
responders
Scuba Divers
Scuba divers? What is going on
here?!?
That water sure is heavy!
What happens to the air in a scuba tank?
20 feet
50 feet
?
80 feet
?
?
How does pressure change the
way we breathe?

Scientific case study –
Scuba Steve & friends....
Lab Investigation
Depth
Time


How does depth affect
the diffusion of scuba
tank “gas” into scuba
divers “blood”
How does time under water
change the amount of “gas”
dissolved into a scuba divers
“blood”
20 feet
20 min
40 feet
60 feet
80 feet
40 min
60 min
Results??
300
Time under water
The effect of depth on the
dissolving time of a gas into a
scuba divers blood
The effect of time under water on the
volume of gas in a scuba divers blood
250
Volume of air (ml)
Time in to dissolve (seconds)
Depth of Diver
200
150
100
50
0
20
40
60
80
10
Scuba diver depth (feet)

Gas dissolves into the blood faster as
the diver goes deeper
 The diver will accumulate more gas
into his/her circulatory system on
deeper dives
20
18
16
14
12
10
8
6
4
2
0
20
30
40
50
60
70
Time under water (min)

The volume of air dissolved in the blood
stream increase with time under water
 This gas can bubble out of solution if
pressure is rapidly reduced
What is “the bends”?

Bends =
decompression
sickness (DCS)
 DCS describes a
condition arising from
dissolved gasses
coming out of solution
and forming bubbles
inside the body when
pressure decreases.
 This

 It



happens when…
Too much change (in pressure) too quickly
is more likely to happen if...
A diver spends a long time under water or
does multiple dives
The diver goes very deep
The diver rapidly returns to the surface from
depth
Prevention and Treatment