Branislav Trebatický, Ján Breza ml., Ján Breza st.
Penile erection is a complex phenomenon mediated through the coordinated interaction of the nervous, arterial, venous
and sinusoidal system. The relaxation of the smooth muscles and the dilatation of the sinusoids leads to filling of
the cavernous tissue with the arterial blood, its expansion and to the compression of venous plexuses, which leads to
venous occlusion. The condition of the tension of penile smooth muscles determines haemodynamic processes, which
keep the penis flaccid or they induce erection. The tonus of the smooth muscles of the flaccid penis is increased, vice
versa the erection requires lowering of the smooth muscle tension. The ability to contract of the arterial and trabecular
penile muscle is regulated by many factors: adequate amount of neurotransmitters, hormones and endothelium of
produced systems, calcium homeostasis, the interaction between contractile proteins and effective intercellular communication
between particular cells of the penile smooth muscles. The balance and interaction between the factors of
relaxation and contraction determines the resulting tonus of the smooth penile muscles. So the normal mechanism of
the penile erection depends on fine balance between the contraction and relaxation of the smooth muscles in corpus
cevernosum.