Learning about Blood Flow

Let's learn about blood flow!

No matter how new you are to all of this, you have a basic understanding that blood is the foundation of male sexual health and erectile health (or dysfunction). There are other factors at play; hormones and signaling molecules that send the blood in and keep it there - but let's just focus on the the blood flow in this article.

Blood Flow: Where It Comes In

Arterial Inflow:

• Blood enters the penis through the internal pudendal artery (#1), which branches into:
  • Cavernous arteries: Supply the corpora cavernosa.
  • Bulbourethral artery (#2): Supplies the corpus spongiosum and urethra.
• These arteries bring oxygen-rich blood directly to the erectile tissues.

.. and Goes Out

Venous Outflow:

• Blood exits the penis via the dorsal vein and venous plexuses, which drain into larger veins connected to the systemic venous circulation.

4. Post-Erection (Returning to Flaccid State)

• The sympathetic nervous system is activated after ejaculation or as arousal decreases, releasing norepinephrine.
• Smooth muscle in the erectile tissue contracts, reducing arterial inflow.
• Venous outflow resumes, allowing blood to leave the penis and return to its flaccid state.

Summary

1. The penis consists of spongy erectile tissue (not bone) designed to fill with blood during arousal.
2. Blood flows in through the internal pudendal artery and its branches (cavernous and bulbourethral arteries).
3. Blood leaves through the dorsal vein and related venous pathways.
4. The process is controlled by nerve signals (nitric oxide for relaxation and norepinephrine for contraction), enabling or halting blood flow.