Compare the organisation of the tunica media of this helicine artery with a "normal" muscular artery
The tunica media of this helicine artery contains an inner longitudinal layer of smooth muscle and an outer circular layer of smooth muscle
When the tunica media contracts (its usual state) the lumen of the artery is occluded and no blood will pass through
These arteries supply sinusoids (spaces) in the erectile tissue which causes the organ to become erect (penis/clitoris)
The supply of oxygen and nutrients to these tissues is provided by "normal" arteries
This micrograph shows a helicine artery supplying the erectile tissue of the penis, similar arteries supply the erectile tissue of the clitoris (L = lumen of artery)