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Physiology

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Respiration

Question
16 out of 33
 

True about pulmonary circulation: (LQ)



A Hypoxia causes vasoconstriction

B Blood volume in lung is 450 ml

C It has low resistance

D All of the above

Ans. D Hypoxia causes vasoconstriction, Blood volume in lung is 450 ml, It has low resistance

Pulmonary circulation:

I. The blood flow through the lungs is essentially equal to cardiac out

II. The blood volume of the lungs is about 450 ml. about 9% of the total blood volume of –the circulation. Approximately 70 ml of this is in the pulmonary capillaries, and the remainder is divided about equally between the arteries and the veins.

III. The pulmonary veins are an important blood reservoir because of their distensibility. When a normal individual lies down, the pulmonary blood volume increases by up to 400 mi, and when the person stands up this blood is discharged into general circulation. This shift is the cause of the les in vital capacity in the supine position and is responsible for the occurance of orthopnea in heart failure.

IV. The entire pulmonary vascular system is a distensible low pressure system.

a. Pul. arterial pressure 24/9 Hg and mean pressure is about 15 mm Hg

b. Pul. capillary pressure 10 mm Hg.

V. Hypoxia ( O2 tension) pH, and CO2 conc. causes Vasoconstriction in lungs.

Respiration Flashcard List

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