Special Circulations

Question 1

What are the adaptations of the pulmonary circulations to promote efficient gas exchange?

Answer 1

Very high density of capilleries in alveolar wall, causes a large capillary surface area, short diffusion distance, causes a large surface area and short diffusion distance, and the combined enodtheilum and epithelium distance is 0.3 um.

Question 2

What is the ventiliation/perfusion ratio?

Answer 2

Need to match the ventiilation of the alveoli with perfusion, maintaine this involves diverting blood from not well ventiliated alveloi.

Question 3

What is hypoxic pulmonary vasoconstriction?

Answer 3

It hleps to give the optimal diffusion/perfusion ratio, and causes avelor hypoxia, and the vasoconstriction of pulmonary vessels so that the poorly ventilated alveolo are less well perfused

Question 4

How are the low pressure pulmonary vessels influenced by gravity?

Answer 4

In the upright orthostatic position there is a greater hydrostatic pressure in vvessles in the lower prt of the lung, and in the apex the vessels collapse during diastole, the level of eart the vessels are continuously patent and the base, vessels distance is increased hydrostatic pressure.

Question 5

What are the effects of excericse on pulmonary blood flow?

Answer 5

Increased cardiac output causes a small increase in pulmnary and atrial pressure, opens the apical capilleries and causes increased O2 uptake by lungs.

Question 6

How is tissue fluid formed?

Answer 6

Hydrostatic pressure of blood within the capillary pushes fulid out, and ontoic pressure (colloid osmotic pressure draws the fluid back into the capillary.

Question 7

Which pressure has more of a impact on the formation of tissue fluid?

Answer 7

The venous pressure

Question 8

What are the two different blood supplies to the lungs?

Answer 8

The Brachial circulation nd the pulmonary circulation