General Penis Anatomy
Understanding erectile dysfunction requires a basic knowledge of penis anatomy and the complex process of creating and sustaining an erection. An erection doesn’t just happen: it requires nerve impulses, muscles, and blood vessels to all work together. Interrupting the process at any stage can cause impotence. Penis anatomy is remarkably complex: the information on this page provides definitions for the most important parts.
The Corpora Cavernosa
The corpora cavernosa are two chambers that fill most of the penis. The chambers are filled with a spongy tissue that includes muscles, open spaces, veins and arteries. An erection occurs when the corpora cavernosa become engorged with blood and expand.
The Tunica Albuginea
A membrane called the tunica albuginea surrounds the corpora cavenosa. This membrane helps keep blood in the penis during an erection.
Urethra
The urethra is the tube through which urine travels. Ejaculate also travels through the urethra. It runs down the underside of the penis, beneath the corpora cavernosa and widens at its opening, called the meatus. The meatus is located at the glans (the head of the penis).
Corpus Spongiosum
The corpus spongiosum is a chamber that surrounds the urethra. It becomes engorged with blood during an erection.
The Prostate
The prostate is a small gland located in the pelvis. It surrounds the urethra and plays an important role in ejaculation. Sperm, which is produced in the testicles and stored in the seminal vesicles, is mixed with prostatic fluid and secretions from the bulbourethral gland to form semen. During ejaculation, semen is expelled through the urethra from the ejaculatory ducts.
The Mechanics of an Erection.
An erection begins with the nervous system. Messages from the brain travel to nerves within the penis and cause the penile muscles to relax. This relaxation allows blood to flow into the chambers of the corpora cavernosa. The pressure from the blood causes the chambers to expand, increasing the size and firmness of the penis. When the muscles contract, the blood flows out of the chambers, signaling the end of the erection.
Many factors are at work here: the nervous system, blood flow, and the action of muscles. Problems at any point in the process can shorten the duration of an erection or even prevent one from occurring. Many of those problems are physical, and are listed on the Medical Causes page.
Physical Erectile Dysfunction Causes
Erectile dysfunction causes are most often physical in nature. Over seventy percent of all cases of erectile dysfunction are physical. Surgery, hypercholesterolemia, diabetes, hypertension and a wide range of other diseases can cause it. Risk factors are cumulative: a man who has had prostate surgery and suffers from hypertension is at greater risk of erectile dysfunction than he would be if he only experienced one of the conditions.
Age and Erectile Dysfunction
Age has long been associated with sexual problems, and many men think that erectile dysfunction is simply a natural part of growing older. While the risk of impotence does increase with age, there’s no reason you can’t enjoy a healthy sex life well into old age. Risk factors that can cause impotence increase as we age, but you shouldn’t assume that you’re “just getting old” if you experience erection problems. Treating the underlying cause can help you regain your sexual health.
Trauma, Surgery and the Prostate
The process of developing and maintaining an erection is a complex interplay of nerve impulses and blood flow. Damage to the nerve endings, muscles and arteries of the penis can disrupt the process. Prostate surgery or any surgery in the pelvic area may cause damage that leads to erectile dysfunction. Spinal cord injuries can also disrupt nerve impulses.
Neurological Erectile Dysfunction Causes
In addition to surgery and trauma, certain neurological disorders can affect nerves associated with erections. Multiple sclerosis and strokes, for instance, may cause nerve damage, as can chronic alcoholism. Diabetes can also damage nerves: between thirty to fifty percent of men with diabetes suffer some degree of erectile dysfunction.
Vascular Diseases
Blood flow is another important factor: if the penis cannot trap and store blood, an erection is simply not possible. Vascular diseases, including hypertension and heart disease, can alter blood flow enough to cause erection problems. Diabetes presents a double threat: the disease affects both blood flow and the nervous system.
Hypercholesterolemia is a condition of increased blood cholesterol, which greatly increases the chances of heart disease at an early age. The condition also increases the risk of erectile dysfunction. The excess cholesterol associated with hypercholesterolemia causes hardening of the arteries, which in turn affects blood flow.
Peyronie’s Disease
Many men have a slight curve to their erect penis. Men suffering from Peyronie’s disease develop a severe curve in the penis, which can make intercourse painful, or even impossible. The condition occurs when fibrous tissue or scar tissue builds up in the penis. Exactly how this tissue forms in unclear, although trauma of some sort is likely to blame. Peyronie’s disease occasionally causes erectile dysfunction, as the tissue interferes with the penis’ ability to retain blood. Surgical correction of Peyronie’s disease can cause damage to the penis, which can also lead to impotence.
Diagnosing Sexual Dysfunction
Sexual dysfunction and difficulty maintaining an erection require a doctor’s diagnosis before treatment can begin. Diagnosis of erectile dysfunction is a complex procedure: root causes may include inadequate testosterone levels, medical conditions, psychological factors or a lowered interest in intercourse. Both the cause and the nature of the sexual dysfunction must be identified.
Discussing erectile dysfunction is difficult for many men. Even some male doctors shy away from the topic. Maintaining an erection during intercourse is seen as an essential part of manhood and not being able to do so is not something most men want to admit to, even in the relatively safe confines of their doctor’s office. For this reason, only about ten percent of all men with erectile dysfunction seek medical help, and remain unaware of treatment options.
The Initial Examination
Besides undergoing a physical examination, you can expect to answer a lot of questions during your first doctor’s visit. Your doctor will develop medical, psychological, and sexual histories to help identify possible causes of your condition. Be as honest as you can: the more accurate your information, the more helpful it is to your doctor.
Erectile dysfunction was once considered primarily a psychological disorder, but recent research has revealed that physical disorders actually account for seventy percent of all cases. Report any existing medical condition. Both prescription and illegal drugs can prevent a man from maintaining an erection.
If your doctor suspects a physical cause, you will probably be sent for lab tests. Diagnosing erectile dysfunction often requires several tests, including measuring testosterone levels, blood tests and urine samples.
Specific Tests
A number of specific tests may be used during the diagnosis. During the physical exam, the doctor may test the penis for normal responses to touch. Failure to respond could indicate nerve damage.
Most men have involuntary erections while they sleep. You may be monitored for nocturnal erections. While not one hundred percent consistent as a diagnostic, an absence of erections while asleep often points to a physical cause. If you have erections while asleep but not while awake, a psychological cause could be the problem.
A penile injection is one of the many tests that may be administered during a diagnostic workup for sexual dysfunction. Medications that cause the penile arteries to dilate are administered during a penile injection. This allows blood to flow into the penis, resulting in an erection. A penile injection allows the doctor to evaluate your capacity to achieve and maintain an erection.
Blood flow problems are often linked to erectile dysfunction. Your doctor may order an ultrasound to examine the penile arteries. The test allows the doctor to check for blood obstructions or irregularities in blood flow. The penis’s ability to trap blood for an erection is also observed. A cavernosography test may also be ordered. A dye is injected into the bloodstream so the doctor can view any problems with penile blood flow on the ultrasound.
Other Conditions
Other forms of sexual dysfunction can easily be confused with erectile dysfunction. Erectile dysfunction has a very specific medical definition: the inability to maintain an erection long enough for intercourse, or the complete absence of an erection. Here are some conditions commonly mistaken for erectile dysfunction:
Premature ejaculation:Â This occurs when a man ejaculates before he intends to. Premature ejaculation rarely has a physical cause: anxiety and over-stimulation often cause the condition.
Delayed ejaculation:Â In this case, a man is either unable to ejaculate, or can only do so after prolonged intercourse. Like premature ejaculation, delayed ejaculation usually has psychological origins.
Prolonged refractory period:Â The refractory period is the time span after ejaculation when a second ejaculation is simply not possible. This period varies from one man to another. Age tends to lengthen the refractory period.
Lack of sexual desire:Â An absence of sexual desire may be physical or psychological in nature. Low testosterone levels may impair the level of arousal. Emotional problems may also lower sexual desire.
Physical Erectile Dysfunction Causes
Erectile dysfunction causes are most often physical in nature. Over seventy percent of all cases of erectile dysfunction are physical. Surgery, hypercholesterolemia, diabetes, hypertension and a wide range of other diseases can cause it. Risk factors are cumulative: a man who has had prostate surgery and suffers from hypertension is at greater risk of erectile dysfunction than he would be if he only experienced one of the conditions.
Age and Erectile Dysfunction
Age has long been associated with sexual problems, and many men think that erectile dysfunction is simply a natural part of growing older. While the risk of impotence does increase with age, there’s no reason you can’t enjoy a healthy sex life well into old age. Risk factors that can cause impotence increase as we age, but you shouldn’t assume that you’re “just getting old” if you experience erection problems. Treating the underlying cause can help you regain your sexual health.
Trauma, Surgery and the Prostate
The process of developing and maintaining an erection is a complex interplay of nerve impulses and blood flow. Damage to the nerve endings, muscles and arteries of the penis can disrupt the process. Prostate surgery or any surgery in the pelvic area may cause damage that leads to erectile dysfunction. Spinal cord injuries can also disrupt nerve impulses.
Neurological Erectile Dysfunction Causes
In addition to surgery and trauma, certain neurological disorders can affect nerves associated with erections. Multiple sclerosis and strokes, for instance, may cause nerve damage, as can chronic alcoholism. Diabetes can also damage nerves: between thirty to fifty percent of men with diabetes suffer some degree of erectile dysfunction.
Vascular Diseases
Blood flow is another important factor: if the penis cannot trap and store blood, an erection is simply not possible. Vascular diseases, including hypertension and heart disease, can alter blood flow enough to cause erection problems. Diabetes presents a double threat: the disease affects both blood flow and the nervous system.
Hypercholesterolemia is a condition of increased blood cholesterol, which greatly increases the chances of heart disease at an early age. The condition also increases the risk of erectile dysfunction. The excess cholesterol associated with hypercholesterolemia causes hardening of the arteries, which in turn affects blood flow.
Peyronie’s Disease
Many men have a slight curve to their erect penis. Men suffering from Peyronie’s disease develop a severe curve in the penis, which can make intercourse painful, or even impossible. The condition occurs when fibrous tissue or scar tissue builds up in the penis. Exactly how this tissue forms in unclear, although trauma of some sort is likely to blame. Peyronie’s disease occasionally causes erectile dysfunction, as the tissue interferes with the penis’ ability to retain blood. Surgical correction of Peyronie’s disease can cause damage to the penis, which can also lead to impotence.
Chemical and Psychological Impotence Causes
Although erectile dysfunction usually has a physical cause, thirty percent of impotence cases are of chemical or psychological origins. The cause may be as simple as an adverse reaction to medication. In spite of the long-standing belief that erectile dysfunction is “all in your mind,” only ten to twenty percent of impotence causes are psychological.
Antidepressants and Other Prescription Drugs
Erectile dysfunction may be caused by a long list of prescription drugs, including common antidepressants and antihistamines. MAO inhibitors, SSRIs (selective serotonin reuptake inhibitors), lithium and the various tricyclic antidepressants have all been linked to MED.
Sedatives, antipsychotic drugs, hypertension medications and corticosteroids have also been known to cause erectile dysfunction. Simply altering the prescribed dose or switching medications often resolves the problem.
Smoking, Alcoholism, and Drug Use
Substance abuse can cause long-term damage to the nervous system, which can in turn lead to erectile dysfunction. Smoking hardens arteries, affecting proper blood flow. Changes in blood flow can affect the penis’s capacity to store blood. Long-term alcohol abuse damages the nervous system and interferes with nerve signals necessary for maintaining an erection. Certain illicit drugs are also known to cause erectile dysfunction. These include heroin, marijuana and anabolic steroids.
Low Testosterone
Men with low testosterone levels can usually maintain an erection. Although low testosterone levels significantly lower a man’s sex drive and cause a loss of libido, the condition is not the same as erectile dysfunction and requires different treatment.
Depression and Other Psychological Considerations
Sexual performance can be affected by certain psychological factors. Of these, depression and anxiety appear to be the most common causes. Depression causes erectile dysfunction by affecting the brain’s ability to become aroused, effectively stopping an erection before it even starts. A certain level of relaxation is necessary to become aroused, so anxiety and stress can also prevent erections.
Some men become very anxious and worried about their sexual performance. This creates a vicious cycle. They worry that their sexual performance will not satisfy their partner, which prevents arousal and causes erectile dysfunction. This “failure” only makes them worry more about their sexual ability, and so on.
Secondary Psychological Conditions
Depression, anxiety and stress often present in men with erectile dysfunction. However, in many cases the psychological problems are the result of impotence, and not the actual cause. Erectile dysfunction puts a man under enormous stress and often leads to depression. Care must be taken to determine whether the emotional disorder is the cause or consequence of erectile dysfunction.
Fatigue
Fatigue is a common cause of impotence. A man who is run down physically and mentally is unlikely to be very interested in sex. Fortunately, most cases of fatigue-based impotence are temporary: resolve the fatigue and the impotence usually disappears. Many medical conditions can cause fatigue, so consulting with your doctor is essential.
Relationship Problems
Difficult or stressful relationships can also cause impotence. Resentment, anger or guilt directed towards your partner can cause erectile dysfunction, as can a lack of sexual interest in your partner. Generally, therapists prefer to treat both partners and work towards a solution for the couple.
A man may try to hide his impotence from his partner, who wonders why he no longer seems sexually interested. Difficult though it can be to admit to erection difficulties, being honest with your partner can help both of you avoid misunderstandings.
Erectile Dysfunction: Defining Sexual Disorders
Male erectile dysfunction, sometimes called impotence or simply MED, is defined as a consistent inability to achieve and maintain an erection. Many men occasionally experience this problem, either due to fatigue, emotional distress or illness. This is quite normal and usually temporary. If the problem persists, an underlying medical problem may be the cause.
Difficulty achieving erections and the negative effect this has on a couple’s sex life can devastate a man’s self-esteem and damage his relationship with his partner. Society equates the ability to perform sexually with manhood, so men suffering from erectile dysfunction are often ashamed of the condition and unwilling to seek professional help.
An estimated ten to twenty million men in the United States suffer from impotence, yet only ten percent ask their doctors for help. Erectile dysfunction is often caused by an underlying medical problem, however, and generally responds well to treatment.
Other Sexual Disorders
Erection difficulties are often confused with other sexual disorders. Problems such as premature or delayed ejaculation are actually very different from erectile dysfunction, and require different treatment methods. Men sometimes confuse a lengthy refractory period with erection problems. In fact, the refractory period is simply the time span following ejaculation when a second ejaculation is impossible. This period becomes longer with age.
Glossary
The terms used to talk about erectile dysfunction are often confusing. Here’s a quick reference to terms you’ll probably hear:
Aphrodisiac:Â Any substance that increases sexual desire. Although many online products claim to be aphrodisiacs, very few have any effect on sex drive. Even a true aphrodisiac may not help treat erectile dysfunction, as underlying medical problems can cause the condition.
Endocrinology:Â The study of the endocrine glands. Endocrine glands produce hormones that affect sexual drive.
Impotence:Â A common term for erectile dysfunction. “Impotence” is not as clinically accurate a term as erectile dysfunction, and carries negative connotations of powerlessness and a lack of manhood. Most doctors prefer to use the term erectile dysfunction.
Libido:Â Libido is a person’s interest in sex. Emotional distress, illness and other factors can have a significant impact on libido.
Penile:Â A term meaning ‘of the penis.’
Testosterone:Â Testosterone is the primary male sex hormone, and is responsible for the development of male secondary sex characteristics.
Urology:Â Urology is the study of the urinary system, and of the male sex organs. A urologist is a specialist in urology.
Vascular Disease:Â A broad term for disease of the blood vessels (veins and arteries). The penis traps blood in order to become erect. Problems with blood flow often cause erectile dysfunction.