Male Anatomy and Behavior
We have already covered male anatomy but lets review some points before going further. The stallion penis has a musculo-vascular structure. In this type of penis, erection occurs as the arteries dilate and the veins constrict. In other words, the inflow is increased and the outflow is decreased. The large cavities within the corpus cavernosum then become filled with blood. This process occurs rather slowly over the course of 2 - 3 minutes. To maintain the erection then requires continual sexual stimuli from visual, olfactory and auditory input.
The initial stimulation that causes erection also triggers emission. This is the process of sperm moving up to the colliculus seminalis and mixing with accessory gland fluid. The process of ejaculation then occurs as a reflex response to continued sexual stimulation. This stimulation is a combination of friction and heat (body heat) stimulation of the glans penis. Importantly psychic stimulation from the brain is also critical. Once ejaculation is triggered, contractions of the epididymis, vas deferens, penile urethral muscle and bulbocavernosus muscle propel the sperm out of the penis into the female. It is the contractions of this last muscle that is responsible for the flagging action of the tail when ejaculation is occurring. The continued contractions of accessory glands mixes more fluid with the sperm as ejaculation progresses.
A question is often raised as to if the male learns the sexual behavior or if it is innate? It appears that it must be innate as males raised in complete isolation learn to mate normally when introduced to the correct environment.
Effects of