Veterinary Andrology and Reproductive Techniques

ERECTION

• The penile erection requires a series of neural and vasomotor reactions.
• Erection is characterized by the marked increase in rigidity of the penis.
• The rigidity is due to elevated arterial blood flow, dilatation of corporal sinusoids, restricted venous outflow, elevated intra penile pressure and relaxation of the retractor penis muscle.
• The penis of the bull, ram and boar is fibroelastic in nature and is having sigmoid flexure.
• Therefore during erection in these species the diameter will not increase much.
• In stallions, the penis is vascular in nature and it is not having sigmoid flexure.
• So there is significant enlargement in size of the penis occurs in this species.
• The erection is predominantly under the control of parasympathetic nervous system.
• The reflex stimulation of the testis, urethra, prostate and glanspenis cause erection.