Correct answer:

Continence is partly a function of the anal sphincters, and partly a consequence of the anal cushions. The anal cushions comprise highly vascular tissue lining the anal canal, with a rich blood supply from the rectal arteries, which anastomose with the draining veins both through capillaries and through direct arteriovenous shunts. The draining veins form saccules, commonly just below the dentate line, which then drain via the superior rectal vein. The venous saccules are supported by smooth muscle to form the cushions. Apposition of these subepithelial vascular cushions is important for continence of gas and fluid.