Which of the following factors is not part of the control of blood pressure?

The control of blood pressure is a complex process that involves several physiological factors. Heart rate plays a crucial role as it directly influences the volume of blood being pumped into circulation per minute, thereby affecting blood pressure. Blood volume is also a significant factor; an increase in blood volume typically results in higher blood pressure due to more fluid in the circulatory system. The condition of blood vessels, such as their diameter and elasticity, impacts peripheral resistance, which is a key determinant of blood pressure.

On the other hand, environmental temperature does not directly influence the regulation of blood pressure. While extreme temperatures can cause changes in blood flow (for example, vasodilation in heat), it is not considered a primary factor that the body uses to control blood pressure. Instead, the body utilizes mechanisms like hormonal regulation, nervous system responses, and changes in heart function and blood vessel characteristics to maintain blood pressure homeostasis. Therefore, environmental temperature stands out as the factor not directly involved in the regulation of blood pressure.