SEXUAL AROUSAL AND ERECTION IN THE MALE: THAT THREE REFLEX MECHANISMS
Carlos Beyer of the Metropolitian University in Mexico, speaking at a symposium on 'Reproduction Endocrinology', stated that three reflex mechanisms are involved in copulatory behaviour. They are the Arousal Mechanism (AM) which turns us on, a separate mechanism for having intercourse called the Copulatory Mechanism (CM), and a Modulatory or Regulating Mechanism (MM) which is responsible for the control of sexual behaviour in man.
The Arousal Mechanism is stimulated in males by the female hormones and is located in the hypothalamus and preoptic area of the brain. It has been found that lesions in this area suppress male sexual behaviour. The Arousal Mechanism arouses you sexually, gets you in the mood for mating and directs the Copulatory Mechanism, 'On your mark, get set, go!' It fires the shot that sets the pace for the Olympic race (intercourse), of which the erect penis is the torch-bearer.
Copulation is a complex process involving the brain, the spinal cord and the motor pathways in the nervous system. Its headquarters are probably situated in the brain near the Arousal Mechanism. It is responsible for co-ordinating the complicated act of intercourse, involving the erection of the penis and all the muscular and vascular changes in the body, preparatory to and during intercourse. The Arousal Mechanism, as I have stated before, stimulates the Copulatory Mechanism. No arousal, no erection, no copulation.
Erection and ejaculation are reflex phenomena—not under the direct control of the brain—and can take place even in the 'spinal' man. During the Second World War there were cases of wounded men whose spinal cords were injured by a fracture of the spinal column or cut due to gunshot injuries. The individual became completely paralysed below the level of the cord injury (spinal man). After some time when the reflexes returned, stimulation of the glans penis or the inner part of the thighs produced a reflex erection of the penis as the erection centre in the cord can act on its own without the intervention of the brain. But the feeling of pleasure is absent, as the wiring from the spinal cord to the centre is severed.
Men's Health-Erectile Dysfunction