<prompt> An arteriole with a damaged endothelial cell layer will not:Constrict when intravascular pressure is increasedDilate when adenosine is applied to the vessel wallConstrict in response to norepinephrineDilate in response to adenosine diphosphate ADP or acetylcholine  <response>: Ans. D. Dilate in response to adenosine diphosphate ADP or acetylcholineBoth adenosine diphosphate ADP and acetylcholine cause the release of NO from endothelial cells. The other choices involve mechanisms that function without endothelial cells. 