The Anatomy of The Penis

The penis is a multifunctional male organ involved in both reproduction and urination. It is divided into three main parts: the glans, body, and root. The penis contains paired corpora cavernosa on the dorsal side and a single corpus spongiosum on the ventral side, which houses the urethra. The tunica albuginea is a fibrous sheath surrounding the corpora cavernosa, providing rigidity. Buck’s fascia, also known as the deep fascia of the penis, covers both the corpora cavernosa and corpus spongiosum. The root of the penis includes the bulb and crura, along with the ischiocavernosus and bulbospongiosus muscles, which contain erectile tissue.

The body of the penis, mainly consisting of the corpora cavernosa, corpus spongiosum, and spongy urethra, is suspended and lacks muscles. The glans, the distal part, features the meatus at its tip, which is the opening to the urethra. The prepuce or foreskin covers the glans, and the frenulum of the prepuce connects it to the urethral surface. Supporting ligaments, such as the suspensory and fundiform ligaments, provide additional structural support. The suspensory ligament arises from the pubic symphysis. In contrast, the fundiform ligament descends from the linea alba, splitting to surround the penis and merging with the dartos fascia to form the scrotal septum. Together, these structures ensure the proper function and stability of the penis.

What Is An Erection?

An erection is when your penis becomes hard and enlarged due to an increase in blood flow. This increase makes your penis stand up and away from your body. Sexual stimulation or excitement usually causes an erection, but random or spontaneous erections can also happen. Erections typically subside after ejaculation but can go away without it as well. 

An erection starts with sensory and mental stimulation in your brain, which sends messages to your penis through your nerves. These messages tell the muscles in the corpora cavernosa (spongy tissue) to relax, allowing blood to flow in and fill the spaces. As the blood vessels in the corpora cavernosa relax and open up, blood rushes in, becoming trapped under high pressure by a series of valves, creating an erection. The tunica albuginea, a membrane surrounding the corpora cavernosa, helps trap the blood, keeping the penis rigid. When the muscles in your penis contract, blood flow stops, pressure decreases, and the valves open, allowing blood to flow out. This causes your penis to lose its erection and become flaccid (soft).

What is Erectile Dysfunction?

Erectile dysfunction (impotence) is the persistent inability to achieve or maintain an erection firm enough for sexual activity. While occasional erection difficulties aren’t usually a concern, ongoing erectile dysfunction can lead to stress, damage self-confidence, and cause relationship problems. It may also indicate underlying health issues like cardiovascular disease or diabetes that need treatment. If erectile dysfunction is a concern, consult your doctor, even if it’s embarrassing. Addressing underlying conditions often reverses erectile dysfunction. Medications or direct treatments such as Extracorporeal Shock Wave Therapy (EWST) may be necessary in other cases.

Causes and Risk Factors of Erectile Dysfunction

Erectile dysfunction can be influenced by numerous factors, including psychogenic, neurogenic, vascular, and drug-induced elements. Lifestyle choices such as alcohol abuse, obesity, and inactivity also play a significant role. Other risk factors include:

• Fatherhood.
• Decreased partner sexual interest.
• Severe impairment during intercourse or masturbation.
• Decreased penile blood flow.

In older men, issues with penile arteries or veins often contribute. Conditions like arteriosclerosis, elevated blood pressure, high cholesterol, and smoking are modifiable risk factors. The causes are usually multifactorial, with sexual performance being impacted by several factors.

Age and Erectile Dysfunction

Age is one of the primary risk factors for erectile dysfunction. As men age, they are more likely to experience conditions such as obesity, hypertension, diabetes, and hyperlipidemia, all of which are common contributors to erectile dysfunction. Studies have consistently shown that the prevalence and severity of erectile dysfunction increase with age. For instance, research indicates that the likelihood of experiencing complete erectile dysfunction triples from 5% in men aged 40 to 15% in men aged 70. The European Male Ageing Study also confirmed that erectile dysfunction becomes more common with advancing age. In essence, ageing is closely linked with erectile dysfunction due to the increased occurrence of health conditions that impair vascular and nerve function, essential for achieving and maintaining an erection.

Erectile Dysfunction and Parkinson’s Disease

Neurogenic erectile dysfunction arises from neurological impairments affecting the ability to achieve or maintain an erection. Parkinson’s disease is one such condition that can lead to erectile dysfunction due to its impact on nerve impulses and libido. Parkinson’s disease alters the dopaminergic pathways responsible for arousal and erection. Studies have shown that men with neurological disabilities, including those with Parkinson’s disease, are significantly more likely to experience erectile dysfunction compared to those without Parkinsons. Additionally, Parkinson’s disease patients often report decreased libido and diminished sexual desire, further contributing to erectile dysfunction.

Vascular Issues as a Cause for Erectile Dysfunction

Vascular problems are a significant cause of erectile dysfunction. Risk factors for cardiovascular disease, such as hypertension, dyslipidemia, smoking, obesity, and diabetes, also contribute to erectile dysfunction. Men with erectile dysfunction have a higher likelihood of experiencing coronary heart disease and stroke. The severity of erectile dysfunction can even predict cardiovascular disease morbidity and mortality. Both erectile dysfunction and cardiovascular disease share the underlying issue of endothelial dysfunction, which impairs blood flow. Obesity, especially abdominal obesity, significantly increases the risk of erectile dysfunction. Androgens, chronic inflammation, and cardiovascular risk factors can exacerbate endothelial dysfunction and atherosclerosis, affecting both penile and coronary circulation. The smaller size of penile arteries compared to coronary arteries means reduced blood flow to erectile tissues.

A meta-analysis of cohort studies has shown that erectile dysfunction significantly raises the risk of cardiovascular disease, coronary heart disease, stroke, and all-cause mortality. Longitudinal studies have demonstrated that men with erectile dysfunction at baseline are more likely to experience cardiovascular events over time. For instance, in the ADVANCE trial, type 2 diabetic men with erectile dysfunction had a higher incidence of cardiovascular disease events.

Smoking as a Cause for Erectile Dysfunction

Smoking is strongly linked to erectile dysfunction. Studies highlight that smokers are more likely to experience erectile dysfunction compared to non-smokers. For instance, research from Spain found that smoking males had a 2.5 times higher incidence of erectile dysfunction than non-smokers. Similarly, an Italian study reported a 1.7 times greater likelihood of erectile dysfunction among smokers compared to non-smokers. Recent meta-analytical findings, including four prospective cohort studies and four case-control studies, revealed that former smokers had an overall odds ratio of 1.29 for developing erectile dysfunction. In contrast, current smokers had a higher odds ratio of 1.51, emphasising the increased risk associated with smoking.

Hormonal Disorders and Erectile Dysfunction

Androgen levels significantly influence the function of the erectile organ. Functional hypogonadism and erectile dysfunction are closely associated with low testosterone levels. Treating men with both testosterone insufficiency and erectile dysfunction poses challenges. In a study focusing on patients with a history of cardiovascular disease, functional hypogonadism, and erectile dysfunction, the effects of testosterone therapy (TTh) on anthropometric and metabolic parameters were evaluated. The study found a 5.4 increase in the International Index of Erectile Function (IIEF) score among hypogonadal men receiving TTh. In a placebo-controlled trial involving patients with late-onset hypogonadism, Tribulus Terrestris was compared to a placebo for treating erectile dysfunction and lower urinary tract symptoms. The study reaffirmed previous findings on the potent effects of this herbal remedy in boosting testosterone levels and improving sexual performance in men with erectile dysfunction and partial androgen insufficiency.

Chronic Inflammation and Erectile Dysfunction

Researchers conducted a study to explore how diet-related inflammation might affect erectile dysfunction. They found that higher levels of dietary inflammatory potential (DII) were linked to increased chances of erectile dysfunction. Erectile dysfunction can be worsened by systemic inflammation and oxidative stress, which damage blood vessel linings. Another study investigated these factors in men with erectile dysfunction, using markers like the oxidative stress index (OSI). Elevated levels of inflammatory markers in the blood are also associated with poorer erectile function. Recent research has shown that erectile dysfunction linked to inflammation involves changes in signalling pathways necessary for blood vessel function, affected by cytokines and chemokines. Factors like salt intake can influence this pathway. 

Rheumatoid Arthritis and Erectile Dysfunction

Sexual health among individuals with rheumatoid arthritis is often overlooked in quality-of-life assessments by healthcare providers. Studies indicate that between 31% and 76% of people with rheumatoid arthritis experience sexual problems influenced by both the disease itself and its treatments. Men with rheumatoid arthritis are particularly susceptible to sexual dysfunction, including erectile dysfunction. Research published in the Journal of Rheumatology found that over half of men with rheumatoid arthritis reported some form of sexual dysfunction, with a higher prevalence of erectile dysfunction compared to men without rheumatoid arthritis (55% vs. 30%). 

Rheumatoid arthritis, characterised by chronic joint inflammation, significantly impacts various aspects of life, including social, economic, psychological, and sexual well-being. Studies have shown that rheumatoid arthritis can lead to conditions like hypogonadism and sexual dysfunction, affecting desire and erectile function. A cross-sectional study at a Danish university hospital also highlighted high rates of sexual dysfunction among rheumatoid arthritis patients.