Editing Normal Erectile Physiology (section)

==== '''<span style="color:#ff0000">Transition to erection/tumescence</span>''' ====
*'''<span style="color:#ff0000">Sexual stimulation triggers release of neurotransmitters from the parasympathetic cavernous nerve terminals.</span>''' 
*'''This release of neurotransmitters (see above) results in relaxation of these smooth muscles and the following events:'''
*# '''Dilation of the arterioles and arteries''' by increasing blood flow in the diastolic and systolic phases
*# Trapping of the incoming blood by the expanding sinusoids
*# '''Compression of the subtunical venous plexuses''' between the tunica albuginea and the peripheral sinusoids, '''decreasing venous outflow'''
*# Stretching of the tunica to its capacity, which '''occludes the emissary veins''' between the inner circular and outer longitudinal layers and further decreases venous outflow
*# '''Increase in PO2 (≈90 mm Hg) and intracavernous pressure (≈100 mm Hg),''' which raises the penis from the dependent position to the erect state (the full erection phase).
* '''Erection involves sinusoidal relaxation, arterial dilation (increased inflow), and venous compression (decreased outflow)'''
*See [[commons:File:Erection_Development.jpg|Figure demonstrating the development of an erection]]
[[File:Figure 28 01 06.jpg|alt=Anatomic representation of changes to penis during erection.|thumb|582x582px|Anatomic representation of changes to penis during erection. Source: [[commons:File:Figure_28_01_06.jpg|Wikipedia]]|center]]