1. Pulmonary circulation High pressure low flow circulation: Bronchial vessels. Empties into pulmonary veins and enter left heart. Left atrium input, and left ventricle output are about 1-2% grater than that of right ventricular output. Low pressure high flow circulation: Rt. Ventricle-  Pulmonary artery  arterial branches  alv. capill.  Veins  Lt. atrium Lymphatics: From supportive tissue spaces coursing to hilium of lungs and into right thoracic lymph. Duct. Helping to prevent pulmonary edema

3. 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

4. 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 blow out air hard  if the person has left heart failure or mitral valve stenosis or regurgitation the volume can reach 900 ml

6. 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)

7. Regional pulmonary blood flow : 1-Zone 1: No blood flow (capill. pr. < alveol, pr.) - Pts. Breathing against positive pr. - Sever blood loss. 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.

10. Regional pulmonary blood flow :  arterial pressure in pulmonary artery is 25-8 mmHg  at apex systolic 25-15= 10 mmHg  during diastole 8-15 mmHg= -7?  if the person is lying down or exercising only zone 3 can be seen.

11. The effect of increasing C.O on pulmonary blood flow during exercise:  blood flow increases by 4-7 folds through: 1- increasing the # of open capillaries 2- distending all the capillaries to increase the flow rate in each one of them. 3- increasing pulm. Arterial pressure  normally 1 & 2 are enough to cause significant decrease in resistance  3 is not significant to conserve the energy of the right heart & to prevent edema

12. 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= 7+14+8 = 29 mmHg  inward forces = 28 mmHg  mean filtration pr. = 1 mmHg “handled by lymph” lungsSystemic cir. Capillary pressure 7 mmHg17 mmHg Interst. Osm. Pr. 14 mmHg8 mmHg Interst. Neg. pr.-8 mmHg-3 mmHg

14. 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 oxide gas. Safety factors  21 mmHg in acute states  35 mmHg in chronic cases