Question about passage V in BS section of AAMC 4

[MedGrl@2022]

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Hi SDNers,

I just wanted to make sure that I understood Passage V in the Biological Section of AAMC 4. There are two rabbit aorta’s right. One with the endothelium in tack and the other has been removed. The scientists are comparing the two aorta’s. First the scientists expose both to norepinephrine (a neurotransmitter released by the efferent motor neurons of the sympathetic nervous system) which constrict both aortas. Is this when the tension starts rising due to constriction? Then they expose both aortas to increasing concentrations of acetylcholine (a neurotransmitter released by the efferent motor neurons of the parasympathetic nervous system). The increasing concentrations of acetylcholine seem to either both increase the tension in grams of both aorta’s at first or have little effect until 10^-7M in the aorta with the endothelium.

When they are talking about tension in grams are they referring to the partial pressure of gasses the aorta? When I was first taking the exam, I thought that they meant tension of the actual aorta, being more tense versus dilated. Why is the tension measured in grams (is it partial pressure, and if so which gases)?


Thank you for all your help!

 

[MedGrl@2022]

Hi SDNers,

I just wanted to make sure that I understood Passage V in the Biological Section of AAMC 4. There are two rabbit aorta’s right. One with the endothelium in tack and the other has been removed. The scientists are comparing the two aorta’s. First the scientists expose both to norepinephrine (a neurotransmitter released by the efferent motor neurons of the sympathetic nervous system) which constrict both aortas. Is this when the tension starts rising due to constriction? Then they expose both aortas to increasing concentrations of acetylcholine (a neurotransmitter released by the efferent motor neurons of the parasympathetic nervous system). The increasing concentrations of acetylcholine seem to either both increase the tension in grams of both aorta’s at first or have little effect until 10^-7M in the aorta with the endothelium.

When they are talking about tension in grams are they referring to the partial pressure of gasses the aorta? When I was first taking the exam, I thought that they meant tension of the actual aorta, being more tense versus dilated. Why is the tension measured in grams (is it partial pressure, and if so which gases)?


Thank you for all your help!

So was I right about tension and partial pressure?