Which of the following mechanisms are used to regulate blood pressure in the closed circulatory system of vertebrates?
I.changing the force of heart contraction
II.constricting and relaxing smooth muscle in the walls of arterioles
III.opening or closing precapillary sphincters
A) only I and II
B) only I and III
C) only II and III
D) I, II, and III

Question

Quizplus · Accepted Answer

All three mechanisms are used to regulate blood pressure in vertebrates' closed circulatory system. Changing the force of heart contraction adjusts the volume of blood pumped out of the heart, while constricting or relaxing smooth muscles in the arterioles can alter the diameter of blood vessels and subsequently the blood flow to organs. Opening or closing precapillary sphincters acts as a gatekeeper for the exchange of nutrients and gases between blood and tissues. Thus, all these mechanisms work in collaboration to maintain proper blood pressure levels.

Which of the Following Mechanisms Are Used to Regulate Blood