All of the following increase the partial pressure of oxygen in the pulmonary capillaries except?

Question

a. increase partial pressure of oxygen in the alveoli

b. increase pulmonary capillary blood flow

c. increase respiratory membrane surface area

d. increase altitude

one other quick question...

What drug is used to dilate the bronchioles?

a. epinephrine

b. acetylcholine

c. norepinephrine

d. dopamine

Answer 1

ppO2 increases w/ increasing pp in the alveoli, capillary blood flow, and surface area. Altitude has an inverse relationship with  ppO2, since it decreases the higher up you are. Eg, Denver is a mile above sea level, and the O2 level is much lower there, and requires acclimation which occurs over a period of several days.

The biochemical pathway is dopamine --> norepi --> epinephrine.

Acetylcholine is a cholinergic while the others (the catecholamines) are adrenergic. Dopamine's effects are dose dependent. At the lowest doses, it acts as a vaso-constrictor, to increase renal pressure, or in shock, cardiac output and bp.

Epinephrine is the drug used for bronchodilation. Eg, peanut allergy results in bronchoconstriction, and use of an Epipen dispenses enough drug to dilate the vessels.

http://en.wikipedia.org/wiki/EpiPen

Answer 2

Altitude does not increase the partial pressure of oxygen in the pulmonary capillaries, because there is less partial pressure of O2 in the atmosphere, so less is absorbed in the lungs.  

the answer your teacher is probably looking for is epinephrine, but  Dopamine also induces bronchial dilation in people with asthma, but not in normal subjects.

Answer 3

d,a