Physical Factors Involved in penile erections
May 28th, 2007 by 
Eric
Physical, tactile, stimulation of the penis arouses and activates the sensory nerve fibres on the surface of the penis. Specialised nerve fibres (called afferent fibres) carry this sensory information from the touch receptors on the penis to the spinal cord. This information is then passed along the spinal cord to the brain. The brain processes this stimulatory information and sends out pro-erection signals (signals that trigger erections) back down to the penis via efferent fibres. These efferent signals form the brain stimulate the dilation (widening) of the Pudendal artery (shown in figure 2). This leads to a net increase in blood flow to the penis and produces an erection. This type of erection is referred to as a reflexogenic erection.
There can be various problems in this route from the Penis to brain and Brain to Penis, problems in this pathway can result in impotence due to a physical cause. One such example is in males who haven’t undergone circumcision . In these men the foreskin of the erect penis may be very tight and immobile on the shaft. This can interfere with the normal erection process and result in poor erectile functioning. This condition is known as Phimosis.
