Question

1) Pulmonary arterioles respond to different factors than systemic arterioles because in the lungs, the blood supply is receiving oxygen and delivering carbon dioxide, while in the systemic circulation, it is delivering oxygen, and receiving carbon dioxide. In the pulmonary circuit, arterioles will dilate in well-ventilated areas of the lungs to increase the rate of exchange between capillaries and well-ventilated alveoli. However, in poorly ventilated areas of the lungs, arterioles will constrict in order to re-route blood to well-ventilated areas. Now consider our case of pulmonary oedema, and how that will impact circulation in the pulmonary circuit. (Select two answers).

a) Pulmonary arterioles will dilate

b) Pulmonary arterioles will constrict

c) Pulmonary vascular resistance will increase

d) Pulmonary vascular resistance will decrease

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2) Why would baroreceptors reflex not compensate for these changes?

Answer 1

1) Correct answer - (b) and (c)

Explanation - The pulmonary edema is mainly due to Congestive heart failure due to which the systemic circulation dilates and hypoxia is regulated by pulmonary vasoconstriction.

The vasoconstriction of pulmonary arterioles causes blood to divert from area of less ventilation to area of more ventilation . This pulmonary vasoconstriction Increases the pulmonary vascular resistance this resistance would cause blood to flow in those areas which are more ventilated (i.e. less pulmonary vascular resistance ).

2) Due to systemic system being monitored by baroreceptor the pulmonary system alterations can't be controlled by baroreflex hence it could be the reason of non - compensation by baroreceptor reflex.