This powerpoint presentation will make you explore about the Perfusion and Ventilation in different zones of lungs with its co-relation with pulmonary tuberculosis.

1. Gandaki Medical College
By: Gyaltsen Gurung

2. To define and classify ventilation and perfusion
in lungs.
To describe zone of perfusion in lungs
To describe ventilation perfusion ratio in lungs
To correlate VENTILATION and PERFUSION
ratio with PULMONARY TUBERCULOSIS
OBJECTIVES

3. 
VENTILATION
The rate at which air enters or leaves the lungs.
 Types : i) Pulmonary Ventilation
ii) Alveolar Ventilation
1)Pulmonary Ventilation (minute ventilation or
respiratory minute volume): Is the volume of air
moving in and out of respiratory tract in a given unit of
time during quiet breathing.
INTRODUCTION

4. 
 Pulmonary Ventilation= Tidal volume X Respiratory Rate
= 500 ml x 12/minute
= 6000 ml/minute
2) Alveolar ventilation: It is the amount of air utilized for
gaseous exchange every minute.
Alveolar ventilation
= (Tidal volume – Dead space) X Respiratory Rate
= ( 500 – 150 ) ml x 12/minute
= 4200ml/minute
TYPES OF VENTILATION.....

5. 
 PERFUSION: The movement of blood into
the lungs through pulmonary capillaries.
 VENTILATION/PERFUSION RATIO :
It is the ratio of alveolar ventilation and
the amount of blood that perfuse the alveoli.
Mathematically, V/Q = 0.84
VENTILATION AND PERFUSION

6. 
ZONES OF LUNGS

7. 
Zone 1: No blood flow
Reason: More negative intrapleural pressure alveoli
size↑ & lower arterial pressure due to gravity →
decrease diameter of vessels
 Zone 2: Intermittent blood flow
Reason: arterial pressure is greater than alveolar and
venous pressure. Whereas, venules pressure are
less than alveolar pressure  venules are collapsed
Zone 3: Continuous blood flow
Reason: Due to gravity, there is high pressure →
vasodilation → more blood flow
ZONE OF PERFUSION

8. 
Ventilation and Perfusion
(5ml/minute)
(0.56ml/minute)
(10.3ml/minute)

9. Zone 1: 1.92 L/minute
Reason: Increase size of alveoli
Zone 2: 4 L/minute
Reason: intermittent size of alveoli
Zone 3: 6.5 L/minute
Reason: Decrease size of alveoli
ZONE OF VENTILATION

10. 
It is the ratio of alveolar ventilation and the
amount of blood that perfuse the alveoli.
Calculation:
V/Q= alveolar ventilation ÷ pulmonary blood flow
Alveolar ventilation= 4200ml/minute
Pulmonary blood flow=5000ml/minute
So, V/Q= 0.84
Ventilation/Perfusion (V/Q)
Ratio

11. 
V/Q RATIO IN LUNGS

12. 
Zone 1: Ventilation(V) >>> Perfusion(Q)
V/Q= 3.4 (high)
Zone 2: Ventilation(V) = Perfusion(Q)
V/Q= 0.8 (average)
Zone 3: Perfusion(Q) >>> Ventilation(V)
V/Q=0.63(low)
V/Q IN DIFFERENT
ZONES OF LUNGS

13. Apical Zone of lungs : It is more infected by
Pulmonary Tuberculosis
Reasons: i) There is low perfusion.
ii) There is higher V/Q , higher PO2 and lower
PCO2
(M.tubercle is strict aerobes)
iii) Less of the oxygen is carried away by the
blood in apex of lungs. ( Highest O2 available)
V/Q and PULMONARY
TUBERCULOSIS

14. Zone 1: Ventilation(V) >>> Perfusion(Q)
V/Q= 3.4 (high)
Zone 2: Ventilation(V) = Perfusion(Q)
V/Q= 0.8 (average)
Zone 3: Perfusion(Q) >>> Ventilation(V)
V/Q=0.63(low)
Apex: It is more infected by Pulmonary Tuberculosis
because
SUMMARY

15. 
 Guyton and Hall ( 13th edition) Text Book of Medical
Physiology
 K Sembulingam and Prema Sembulingam(6th
edition) Essentials of Medical Physiology
 Ananthanarayan and Paniker’s( 9th edition)
Text Book of Microbiology
REFERENCES

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