Vasoconstriction in arteries occurs when smooth muscle contracts in which layer?

1. Vessel walls are built in named layers. 2. Vasoconstriction involves smooth muscle in the vessel wall. 3. That smooth muscle sits in a specific layer. 4. It is the smooth muscle in the walls of the tunica media that contracts. 5. Contraction narrows the lumen and raises pressure. _Source: OpenStax Anatomy and Physiology 2e (CC BY 4.0), Ch 20 'The Cardiovascular System: Blood Vessels and Circulation', sections 20.1-20.5_