1. Pulmonary circulation
Physiological anatomy:
the Artery is 5cm thin (1/3 of aorta diameter) , while the branches are short and have more diameter so it will have a large compliance (7 ml/mmHg).
pulmonary veins are thin & short.
bronchial arteries originate from the systemic circulation (carry 1-2% of C.O -oxygenated blood-) then empty into pulmonary veins then to the left atrium so the left ventricle pumps 1-2% more than the right ventricle.
rich lymphatic drainage to the right thoracic duct to prevent edema

2. Pressures in the pulmonary system:
1- right ventricle: 25-1 mmHg
2- pulm. Artery: 25-8 mmHg
3- pulm. cap. : 8 mmHg
4- left atrium & major veins: 2 mmHg
Blood volume of the lungs: :
 450 ml ( 9% of total blood volume)
 70 ml are found in the capillaries

5. Blood volume of the lungs
if the person is bleeding or blowing air out hardly the volume can reach 200 ml. if the person has left heart failure or mitral valve stenosis or regurgitation the volume can reach 900 ml

6. MEASUREMENT OF PULMONARY BLOOD FLOW
Fick Principle
VO2=Q(CaO2-CvO2)
VO2 = Oxygen Consumption
CaO2 = Arterial Content
Q = Blood flow
CvO2 = Venous Content

7. MEASUREMENT OF PULMONARY BLOOD FLOW
VO2=Q(CaO2-CvO2)
CaO2 = 20 ml O2/100 ml blood
VO2 = 250 ml/min
CvO2 = 15 ml O2/100 ml blood
Q = ml O2/min = ml O2 * 100 ml blood
(20-15) ml O2/100 ml blood min ml O2
Q = ml blood /min

8. Blood flow Effect of alveolar [O2]:
 when [O2] decreases below 70% of normal  alveolar epithelial cells secrete vasoconstrictors  adjacent blood vessels constrict  blood flows to better aerated alveoli (extreme low [O2]  5x resistance)
Effect of hydrostatic pressure:
 in normal upright adult there’s a difference between the lowest and highest points of the lung
the gradient is 23 mmHg (15 mmHg above the heart & 8 mmHg below it)

12. Regional pulmonary blood flow :
1-Zone 1: No blood flow
(capill. pr. < alveol, pr.)
2-Zone 2: Intermittent blood flow
3-Zone 3: Continuous blood flow.
(capill. pr. > alveol. pr.)
in normal lungs zone 1 cannot be found, zone 2 is in the apex of the lung and zone 3 represents the base.

15. Regional pulmonary blood flow :
 arterial pressure in pulmonary artery is 25-8 mmHg at apex systolic = 10 mmHg
during diastole 8-15 mmHg= -7?
(Hydrostatic pressure difference is 15 mmHg between the level of the heart and the lung apex)
 if the person is lying down or exercising only zone 3 can be seen.

16. Pulmonary capillary dynamics:  7 mmHg cap. Pressure.
 blood passes through the capillary in 0.8sec
 increasing the C.O lowers the time to 0.3sec
Capillary fluid exchange dynamics:
 outward forces= = 29 mmHg
 inward forces = 28 mmHg
 mean filtration pr. = 1 mmHg “handled by lymph”
lungs
Systemic cir.
Capillary pressure
7 mmHg
17 mmHg
Interst. Osm. Pr.
14 mmHg
8 mmHg
Interst. Neg. pr.
-8 mmHg
-3 mmHg

18. Pulmonary Capillary Dynamics
Outward Forces
Pulmonary capillary pressure 7 mmHg
Interstitial osmotic pressure 14 mmHg
Negative interstitial pressure 8 mmHg
Total mmHg
Inward Forces
Plasma osmotic pressure mmHg
Net filtration pressure mmHg
Negative interstitial pressure keeps alveoli dry

19. Pulmonary Capillary Dynamics
Hydrostatic +7 -8 -8
surface tension
hydrostatic pressure
Osmotic 28 14
Net +1 -5
Lymphatic pump

21. Pulmonary edema
Alveoli are always dry except for a small amount of fluid secreted by alveolar cells on the alveolar surface.
When interstitial pressure becomes (+) water will fill the alveoli
Causes:
1- Left-sided heart failure ↑ venous+cap. pr
2-Damage to the pulmonary capillary membrane caused by :
a- infections
b- breathing chlorine gas or sulfur dioxide gas.
Safety factors 21 mmHg in acute states
35 mmHg in chronic cases

22. Heart Failure and Pulmonary Edema
Edema Formation 25
Left Atrial Pressure

23. Pulmonary Edema Causes of pulmonary edema Safety factor
left heart failure
damage to pulmonary blood cap membrane, as
In pneumonia or breathing chlorine gas or sulfur dioxide gas
Safety factor
negative interstitial pressure
lymphatic pumping
decreased interstitial osmotic pressure

24. Pleural effusion (edema) : Collection of large free fluid in the pleural space
1-Blockage of lymphatic drainage from pleural space
2- Cardiac failure (increase cap pressure)
3- Decrease plasma colloid osmotic pressure
4- Infection or inflammation of the surface of pleural
cavity