 |  From another forum NBME 2 S 1
|
 
|
| Author | 7 Posts |
fox
Forum Guru
Topics: 70
Posts: 727
|
15. The graph shows an isovolumetric pressure-flow curve obtained at 25% of total lung capacity. An increase in which of the following is most likely to increase the plateau value of the expiratory flow rate?
curve showing experatory flow rate on Y-axis and pleural pressure on X-axis. curve shows increase in expiratiory folw rate which platues at 5 L/sec speed at around 20 cm H2O plural pressure and continues to be the same for further rise in pleural pressure.
A) Airway resistance
B) Amount of surfactant in the alveolar space
C) Ciliary beating frequency
D) Expiratory effort
E) Lung volume
F) Parasympathetic activity of fibers innervating the airways
I picked expiratory effort over Lung volume because of the fact that it mentioned 'isovolumetric' -- but i don't know..
Reason i picked is because it increase pressure -- and by increasing pressure i would assume flow rate to increase --- flow=pressure/resistance..
what do you think?
___________________
Aim High
|
| laura81
Forum Elite
Topics: 32
Posts: 175
|
where is the graph?
|
| MRMAVERICK
Forum Guru
Topics: 40
Posts: 713
|
yup where is the graph??????????
|
| fox
Forum Guru
Topics: 70
Posts: 727
|
The graph has been "described" !!!
___________________
Aim High
|
| Leopard
Forum Guru
Topics: 30
Posts: 401
|
Answer is E
Best of luck
___________________
FA is just a good revision book.It is not a "real" learning tool.
|
| fox
Forum Guru
Topics: 70
Posts: 727
|
leopard...could u explain in ur lucid style pls
___________________
Aim High
|
| Leopard
Forum Guru
Topics: 30
Posts: 401
|
Dear
Actually answer is in your stem question
Flow = Pressure gradient /Resisitance
So flow can be increased by
- Either by increasing pressure gradient
- or by Decreasing resistance
At peak epiratory flow (at which plateau has occur).you cannot increase flow by increasing pressure gradient in the lungs (it is a different point of discussion) , so only factor which can be changed is Resistance
Resistance of any tube is inversly proportional to four power of radius of the tube.
In other words greater diameter of air ways less resistance
This diameter is of airways is directly proportional to Lung volume
More lung volum e---------> Less resistance of airways -------------> more peak flow
Best of luck
___________________
FA is just a good revision book.It is not a "real" learning tool.
|
|
| |
| | | | | | | |
You don't have permission to post.
|
