Physiology of penile erection

Blood engorgement results in penile rigidity.

“This blood engorgement finally results in penile rigidity [8].”

In the flaccid penis, smooth muscle cells of corpora cavernosa are contracted and penile blood inflow is low.

“In the flaccid penis, smooth muscle cells of corpora cavernosa are contracted and penile blood inflow is low.”

The tone of penile smooth muscle is a key determinant of the hemodynamic events that maintain penile flaccidity or allow erection.

“The tone of penile smooth muscle is a key determinant of the hemodynamic events that maintain penile flaccidity or allow erection.”

The expanded corpora cavernosa cause mechanical compression of the emissary veins, restricting venous outflow and facilitating entrapment of blood in the cavernosal sinusoids.

“The expanded corpora cavernosa cause mechanical compression of the emissary veins, restricting the venous outflow from the cavernosal spaces and facilitating an entrapment of blood in the cavernosal sinusoids.”

During erection, relaxation of trabecular smooth muscle results in increased blood flow and pressure in the corpora cavernosa and expansion of sinusoidal spaces.

“During erection, relaxation of trabecular smooth muscle results in an increased blood flow and pressure in the corpora cavernosa and an expansion of sinusoidal spaces (Fig. 1).”

Penile erection is a complex neurovascular event involving interaction between the nervous system and the penile smooth muscle system.

“Penile erection is a complex neurovascular event involving the interaction between different systems: The nervous system (central and peripheral) and the penile (arterial and trabecular) smooth muscle system.”