A 19-year-old woman presents with cold hands and

feet. She says that when her hands or feet are exposed to cold, the fingers or

toes become first white and then blue. The fingers return to normal color upon

warming of the hands. The patient is diagnosed with Raynaud´s phenomenon, which

is characterized by an inappropriate vascular response to cold. The affected

vessels are small arteries and arterioles that are responsible for regulating

blood flow to the tissues. The patient would like to know more about her

disease, so she decides to read more about it. Unfortunately, she turns to

untrustworthy internet sources. Which of the following statements that the

patient has read about arterioles on the internet is correct?