Erection - Anatomy & Physiology
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Introduction
- When sexual receptivity of the female is established and sufficient arousal is accomplished in the male, erection and protrusion of the penis ensue.
- Successful penile erection requires a complex series of neural and vasomotor reactions.
- Erection of the penis is necessary for copulation and deposition of semen in the female reproductive tract.
- Erection is characterized by a marked increase in rigidity of the penis.
- Increased rigidity is the result of increase in arterial inflow of blood compared to venous outflow.
- Erection requires that blood be trapped within the cavernous sinus of the penis.
- Increased blood flow to the penis is brought about by vasodilation of the arterioles supplying it.
Erection of the Fibroelastic Penis
- Bull,Ram and Boar
- Involves increased blood flow with subsequent increase in pressure and simultaneous relaxation of the retractor penis muscles.
- Erection and protrusion involve straightening of the penis to eliminate the sigmoid flexure.
- Does not increase significantly in diameter during erection.
Erection of the Musculovascular Penis
- Stallion
- Increases in diameter during erection.
- Retractor penis muscle still relaxes during erection, but no sigmoid flexure.
- Engorgement with blood plays a significant role in the highly vascular penis.