Erections and how they work
The penis has two chambers inside it called the corpora cavernosa. These chambers extend from the head of your penis deep into the pelvis. The insides of these chambers are made of spongy tissue and have the ability to gain blood volume and grow in size.
During your daily activities, the arteries that supply blood to the penis are only partially open, to allow enough blood flow to keep your tissue healthy.
When you experience sexual stimulation, the brain sends signals to trigger a hormonal response that allows those same arteries to open completely.
Those open arteries allow more blood to enter the corpora cavernosa faster than the blood can leave through the veins. As the corpora cavernosa fill and grow in size, the veins get compressed, trapping blood in the penis, causing it to get stiff. This chain reaction continues until you achieve and maintain an erection.
When your brain stops sending signals, the hormones diminish and your arteries go back to their normal state.
E.D. problems begin when our brain doesn’t send enough or any signals, when the blood flow is inadequate, or when erectile tissue is damaged.
3) As the chambers rapidly fill with blood, they expand, and the penis becomes firm and elongated. The result is an erection.