The idea of ​​the anatomical structures described above allows us to understand the processes that occur during sexual intercourse and its disorders: • Against the background of hormone-dependent libido, psychic (exogenous and endogenous) factors contribute to the generation of impulses that reach the sacral center of erection from the hypothalamic center through the spinal cord (psychogenic erection) . • The latter can occur independently of central stimuli, through segmental afferent influences from the genital area (reflex erection).  

• Parasympathetic efferent impulses from the sacral center of erection, which are part of the roots S2 – S4, lead to an erection by regulating the flow of blood into the cavernous bodies.  

• Ejaculation is regulated with the participation of: – sympathetic impulses, which contribute to the secretion of the prostate and seminal vesicles, cause its progression by rhythmic contractions of the smooth muscles of the seminal vesicles and the ejaculatory duct, and prevent backflow of the seed by reducing the internal sphincter of the bladder; – somatosensory efferent effects, which during orgasm cause an intense contraction of the striated muscles of the pelvic floor (bulbocavernous and sciatic-cavernous), which leads to ejaculation and helps to reduce other muscles of the pelvis and hips.  

• Subsequent lowering of the penis is a consequence of, on the one hand, a decrease in parasympathetic influence, on the other hand, a decrease in the flow of arterial blood regulated by the sympathetic system to the cavernous bodies.  

Erectile dysfunction.

The most common psychogenic disorders of potency . To establish this diagnosis, it is necessary: • the absence of changes in the local examination of the genitals; • normal results of a general examination, especially endocrine and autonomic functions (diabetes mellitus); • lack of changes during examination of blood vessels, especially lower legs and lower abdomen; • lack of neurological symptoms. 

In addition, in favor of the psychogenic nature of potency disorders indicate: • the presence of night or morning erections; • the presence of an erection in other special circumstances; • signs of neurotic development, mental conflict, depression, problems with a partner, etc.  

Potency impairment in endocrine diseases sooner or later is accompanied by other signs of endocrine insufficiency. In this case, you should pay attention to the skin condition, beard growth, body hair growth, secondary hypothyroidism. With a pituitary tumor, impotence can be several years ahead of visual field disturbances. It is also necessary to consider the possibility of endocrine psycho-organic syndrome with a decrease in emotional background and motivation. 

Potency disorder with damage to the hypothalamus (or other structures of the brain), as a rule, is accompanied by other signs of a dysfunction of the central nervous system (for example, impaired water balance, hunger, regulation of blood pressure, sleep). For damage to the temporal lobes, erectile dysfunction is also characteristic. 

Many toxic substances and drugs affect the central nervous system . Potency disorders are caused by blood pressure lowering drugs, anticholinergics, alpha methyldopa, barbiturates, phenothiazines, tricyclic antidepressants, monoamine oxidase inhibitors , amphetamine, heroin, cocaine and alcohol. 

Vascular diseases of the arteries of the pelvis and penis can cause a violation of the filling mechanism of the cavernous bodies and lead to impotence. This can be thrombosis of the aortic bifurcation region (Lerish syndrome), thrombosis of the distal pelvic arteries (in particular, after pelvic fractures) or occlusion of the penile arteries in patients with diabetes mellitus or arteriosclerosis (history data, results of palpation and auscultation of vessels, risk factors, if necessary, carry out hyperselective arteriography).