Impotence is often referred to as erectile dysfunction and is the inability of a man to either get or maintain an erection during penetration until ejaculation. It sometimes includes the lack of, or a reduced sense of sexual excitement, which in turn leads to a loss of an erection.
Erection in Love-Making
In order for a man to obtain an erection consciously, he must be sufficiently excited by one or more types of stimuli. The stimulus may be physical or psychological or both.
For example the stimulus can be what he sees or senses or even hears from his partner. It might be his imagination producing thoughts and images that are of a sexual nature. It can be and often is a combination of the two.
All men experience what might be termed "involuntary" erections. This is when the man is not consciously seeking to get an erection but he gets one none the less. The most common time for a man to experience an involuntary erection is when waking in the morning and before emptying the bladder. Overnight the bladder fills and puts pressure on the prostate gland. Stimulating the prostate gland often leads to an erection.
There may be other times during the day or night when a man can experience having an erection, which is not of his choosing. Sometimes a man will be sexually attracted to another person he meets, will not want to have an erection but because he is sexually stimulated will experience an erection.
How Does the Body Get An Erection?
Three chambers are contained in the penis. During an erection these chambers fill will blood making the penis stiff and erect. For most men the girth and the length of the penis increases during an erection.
During sexual stimulation (physical or imagined) or involuntary stimulation, the brain sends a signal to engorge the penis and the blood pressure in the body increases. The three chambers fill with blood and the penis stiffens.
As long the brain experiences or interprets what it perceives as sexual arousal, the penis stays enlarged and blood is prevented from escaping from the penis by local muscles.
Interestingly in the body either the parasympathetic or the sympathetic nervous system are in ascendancy in the body at any one moment in time. For a successful erection the two systems are in balance.
That is why if a man experiences anxiety during love-making it can tip the balance between the parasympathetic or the sympathetic nervous system and lead to impotence.
To summarise, impotence or erectile dysfunction is the loss or the lack of a lasting erection through to ejaculation. Often the erection is lost just before or during penetration.