Erection: The process by which the penis becomes firm and enlarged due to blood filling the corpus cavernosum.
Erectile Dysfunction: A condition where there is difficulty in achieving or maintaining an erection due to various factors affecting the flow of blood into the corpus cavernosum.
Spongiosum: Another spongy structure in the penis that surrounds the urethra and helps keep it open during ejaculation; it does not contribute as directly to erections as the corpus cavernosum