In both cases, an intact neural system is required for a successful and complete erection. Stimulation of the penile shaft by the nervous system leads to the secretion of nitric oxide (NO), which causes the relaxation of the smooth muscles of the corpora cavernosa (the main erectile tissue of the penis), and subsequently penile erection. Additionally, adequate levels of testosterone (produced by the testes) and an intact pituitary gland are required for the development of a healthy erectile system. As can be understood from the mechanisms of a normal erection, impotence may develop due to hormonal deficiency, disorders of the neural system, lack of adequate penile blood supply or psychological problems. Spinal cord injury causes sexual dysfunction, including ED. Restriction of blood flow can arise from impaired endothelial function due to the usual causes associated with coronary artery disease, but can also be caused by prolonged exposure to bright light. Diagnosis
In many cases, the diagnosis can be made based on the persons history of symptoms. In other cases, a physical examination and laboratory investigations are done to rule out more serious causes such as hypogonadism or prolactinoma.One of the first steps is to distinguish between physiological and psychological ED. Determining whether involuntary erections are present is important in eliminating the possibility of psychogenic causes for ED. Obtaining full erections occasionally, such as nocturnal penile tumescence when asleep (that is, when the mind and psychological issues, if any, are less present), tends to suggest that the physical structures are functionally working.
Her relatives received prison terms, the parents dying in jail. In 1988, members of the Carr family from Alturas, Polk County, Florida, fell ill from what appeared to be thallium poisoning. Peggy Carr, the mother, died slowly and painfully from the poison. Her son and stepson were critically ill but eventually recovered. The Carrs neighbor, chemist George J. Trepal, was convicted of murdering Mrs. Carr and attempting to murder her family, and sentenced to death. The thallium was slipped into bottles of Coca-Cola at the Carr and Trepal homes. Thallium was the poison of choice for Saddam Hussein to use on dissidents, which even allowed for them to emigrate before dying. In 1995, Zhu Ling was the victim of an unsolved attempted thallium poisoning in Beijing, China. In 1994, Zhu Ling was a sophomore studying physical chemistry at Tsinghua University in Beijing. She began to show strange and debilitating symptoms at the end of 1994, when she reported experiencing acute stomach pain and extensive hair loss. Ultimately she was diagnosed on Usenet with poisoning by thallium. To this day, there is still speculation among Chinese expatriates overseas as to the poisoners identity. The only suspect of the police investigation, Sun Wei, is a member of a family with high-level political connections, which may have been used to halt and suppress the results of the investigation. Sun Wei was Zhu Lings classmate and roommate in Tsinghua University from 1992–1997. Tsinghua University also said she was the only student who had access to thallium compounds at the school.