Final answer:
Erectile dysfunction (ED) is a chronic disease causing progressive erectile failure. It is associated with various physical and emotional conditions, including aging and certain disorders, which interrupt the vasodilation pathway and prevent erections.
Step-by-step explanation:
Erectile dysfunction (ED) is a condition in which a person has difficulty either initiating or maintaining an erection. It is a chronic disease that causes progressive erectile failure. The prevalence of ED increases with age, reaching nearly 70 percent by 70 years of age. There are various causes of ED, including aging, diabetes, vascular disease, psychiatric disorders, certain drugs, and problems with the testes resulting in low testosterone concentrations. These physical and emotional conditions can lead to interruptions in the vasodilation pathway and result in an inability to achieve an erection.