Ambient temperature is the term used to identify the surrounding or environmental temperature. It is the nature and tendency of all things to approach ambient temperature. If you are in a room, then the ambient temperature is the room temperature.
An arteriole is a small-diameter blood vessel in the microcirculation that extends and branches out from an artery and leads to capillaries. Arterioles have muscular walls and are the primary site of vascular resistance. The greatest change in blood pressure and velocity of blood flow occurs at the transition of arterioles to capillaries.
The arteries branch into smaller and smaller vessels, eventually becoming very small vessels called arterioles. Arteries and arterioles have muscular walls that can adjust their diameter to increase or decrease blood flow to a particular part of the body.