Constriction of the trabecular smooth muscle and helicine arteries induced by sympathetic innervation makes the penis flaccid, with blood pressure in the cavernosal sinuses of the penis near venous pressure. Acetylcholine is thought to decrease sympathetic tone. This may be important in a permissive sense for adequate trabecular smooth muscle relaxation and consequent effective action of other mediators in achieving sufficient inflow of blood into the lacunar spaces. When the trabecular smooth muscle relaxes and helicine arteries dilate in response to parasympathetic stimulation and decreased sympathetic tone, increased blood flow fills the cavernous spaces, increasing the pressure within these spaces so that the penis becomes erect. As the venules are compressed against the tunica albuginea, penile pressure approaches arterial pressure, causing rigidity. Once this state is achieved, arterial inflow is reduced to a level that matches venous outflow.
For example, many men with diabetes mellitus may develop erectile dysfunction during their young and middle adult years. Physicians, diabetes educators, and patients and their families are sometimes unaware of this potential complication. Whatever the causal factors, discomfort of patients and health care providers in discussing sexual issues becomes a barrier to pursuing treatment.
Men who wear tight underwear may also experience the same problems. Because of the constriction, feeling may be lost, and even if unnoticed actively, the brain will notice. This is part of the complication with erectile dysfunction between the brain and the body. While you may be in the mood, if the proper electrical signals are not sent back and forth, nothing will happen.
I’m going to share a secret with you. I understand that for men it’s a big (well, perhaps flaccid and at least momentarily small) deal when you can’t get hard. However, in most instances, women don’t give a fuck. We’re understanding creatures who (ahem) know a thing or two about not being able to get off every time. To ease the awkwardness, here are a few go-to phrases to drop when you just can’t get it up.
Having erection trouble from time to time isn't necessarily a cause for concern. If erectile dysfunction is an ongoing issue, however, it can cause stress, affect your self-confidence and contribute to relationship problems. Problems getting or keeping an erection can also be a sign of an underlying health condition that needs treatment and a risk factor for heart disease.