Final answer:
In males, the corpora cavernosa and corpus spongiosum are the structures considered erectile tissue, filling with blood and causing erection during sexual arousal.
Step-by-step explanation:
The structures that are considered erectile tissue in males are the corpora cavernosa and corpus spongiosum. These columns of erectile tissue are responsible for the erection during sexual arousal. When sexual arousal induces vasodilation, these tissues fill with blood, causing to become erect. The corpora cavernosa consist of two larger lateral chambers running along the top of the shaft, while the corpus spongiosum is a smaller chamber that surrounds the spongy, or penile, urethra and can be felt as a raised ridge on the erect. These erectile tissues not only play a vital role in male sexual function but also contribute to the rigidity necessary for sexual intercourse.