Penile Erection Process

Today, we’re talking about how arousal and sexual desire cause a penile erection. These are healthy and normal processes, but they can be affected by an orgasmic disorder. 

How Arousal or Sexual Desire Cause an Erection

A physical erection has its beginnings in your brain. 

Your senses alert your brain through images, feelings, sounds, or even smells, and it causes your nerves to send messages chemically through your blood vessels that, in turn, stimulate your penis.

These chemical messages relax the arteries and allow more blood to flow into your penis, causing the organ to expand into an erection. At this point, the penile veins close and create pressure within the corpora cavernosa that keeps an erection intact until ejaculation.

You may be asking, “corpora cavernosa, what?” For greater understanding, let’s discuss the anatomy of a penis and its natural functioning.

The Anatomy of a Penis

penis anatomy

A penis is an organ with many parts:

  • The corpora cavernosa is two chambers running the length of a penis, containing many blood vessels that resemble little cavernous spaces similar to a sponge.
  • The urethra is located on the underside of the corpora cavernosa and is a tube that carries sperm or urine.
  • Surrounding the urethra is erectile tissue that holds two main penile arteries, nerves, and veins.
  • The length of the entire penis is called the shaft.
  • The end of the shaft is the glans (the layman’s term for this is the head of the penis).
  • The release point on the tip of the glans is called the meatus. From here, semen or urine discharges.

There Are Two Distinct Types of Erections

When a penis is flaccid, blood flow is balanced from in and out of the organ. Conversely, when you experience a normal and healthy erection, a complex and dynamic process happens in your brain (neural activity) and your vascular system (blood vessels).

Your penis can experience erections because of psychogenic (mental) stimuli or reflexogenic (direct sensory stimuli):

  • A psychogenic erection is caused by visuals, sound, smell, or fantasy stimuli. 
  • A reflexogenic erection stimulates nerves on the penis that transmit messages up the spine, resulting in parasympathetic activity in the brain.

What Is Parasympathetic Activity?

Parasympathetic activity arouses a healthy penis to achieve an erection because it causes blood flow to increase rapidly into the corpora cavernosa.

As blood flow increases, the veins compress and prevent outflow. This physical change creates an intracavernosal pressure that becomes evident as a full erection. 

Full Erection to Ejaculation

At full erection, the head of the penis enlarges, and the penis is engorged to maximum rigidity, allowing ejaculation.

Post orgasm, the penis experiences muscle contractions that cause an outflow of blood from the organ, decreasing the length and girth of the penis back to its flaccid state.

Four Stages of Healthy Male Sexual Response

Male Sexual Response

Male sexuality follows a cycle of four major phases:

  • Sexual Desire
  • Arousal and Ability to Achieve Erection
  • Orgasm and Ejaculation
  • Post-orgasmic Relaxation

Many different types of sexual dysfunctions or orgasmic disorders can impact a man at any stage of his sexual cycle. So let’s discuss each phase more closely.

Sexual Desire

A man’s sex drive, motivation, and wishes make up the first phase of his sexual cycle, and hormones, mental health, social pressures, medications, or substances (alcohol or drugs) can impact desire. But the most significant “driver” in this phase is the human brain, with the hypothalamus playing a considerable role in experiencing sexual desire. 

Two disorders that affect a man’s sexual desire are hypoactive sexual desire disorder (HSDD) and sexual aversion disorder (SAD). In addition, major international medical surveys report just how many men have recently suffered from decreased sexual desire. 

Research shows that men with HSDD may get misdiagnosed as having ED (erectile dysfunction). These are two different sexual dysfunctions, and men should always consult with an expert in sexual health to ensure the correct diagnosis and most effective treatment.

Arousal and Erection

Arousal and erection

Men get aroused by mental and bodily stimulation, and the physical effects of arousal and increased blood flow may cause the penis to change colour and the testicles to elevate. Your heart rate, blood pressure, and breathing also quicken in this phase.

Erectile dysfunction can impact arousal significantly, and ED is often a side effect of various  medical issues or disorders that cause the following physical problems:

  1. Brain signals aren’t working: Multiple sclerosis (MS), Alzheimer’s disease, and Parkinson’s disease are neurological disorders that may cause ED when the brain can’t signal sexual arousal anymore.
  2. Blood flow is inadequate. ED can occur due to elevated blood pressure, heart disease, high cholesterol levels or forms of diabetes that impact blood flow to the penis.
  3. Penis erectile tissue gets damaged. A man undergoing radiation for prostate or bladder cancer may have tissue damage to the penis that affects erections. 

Orgasm and Ejaculation

Physical signs you feel during orgasm and ejaculation include faster breathing, a quicker heart rate and blood pressure, and muscle contractions that are voluntary or involuntary. Ejaculation occurs and is felt in the seminal vesicles as the penis contracts and discharges semen through the urethra. 

ED can be triggered by mental health or physical issues to cause orgasmic disorders, including:

  • The inability to orgasm with a partner during intercourse
  • The inability to orgasm without prolonged (lengthier) sexual stimulation.

Sometimes, orgasm is only possible during self-pleasure (masturbation) or oral sex.

Post-Orgasmic Relaxation 

The last phase in a man’s sexual cycle only happens if they have reached orgasm. If orgasm isn’t achieved, there may be feelings of anger or discomfort that can potentially last for hours. 

Post-orgasmic relaxation lasts between 10-15 minutes when there’s a sense of calmness as the breathing rate, heart rate, and blood pressure decrease to normal levels. Unfortunately, most men can’t achieve another erection during this time (called the refractory period).

What to Do About an Orgasmic Disorder or ED

Orgasmic disorder or ED

The most effective way to properly diagnose an orgasmic disorder is to undergo a thorough examination and evaluate your medical history with a specialist in men’s sexual health. 

This process of examination and evaluation includes:

  • Discussing concerns with sexual function (or dysfunctions)
  • Identifying social pressures, sexual history, and stresses in life, including relationship problems, death of a partner, job loss, or other personal or family issues
  • A physical exam and overall health assessment focus on cardiovascular (heart and blood) health, brain health, and genital health.

During the physical exam, an evaluation of the genitals can identify any physical abnormalities like hypospadias, phimosis, or Peyronie’s disease. The prostate gland gets checked for issues with size, symmetry, and any signs of lumps.

Did you know that your body hair and voice can also help identify signs of hypogonadism? There are many critical parts to a thorough examination that help to ensure a proper diagnosis and the most effective treatment for an orgasmic disorder.

Make a Positive Change in Your Whole Life!

Sexual issues and erectile disorders can impact you tremendously. At OHN, we understand that, as your sexual health specialist, our examinations and evaluations include complete diagnostic testing and treatment solutions proven effective in over ¾ of our patients. 

Contact us today for your free consultation!

MILLER, T., 2000. Diagnostic Evaluation of Erectile Dysfunction. [online] Available at: <> [Accessed 30 April 2022].

Coloplast Men’s Health. n.d. What Makes an Erection Happen & How a Penis Gets Hard. [online] Available at: <> [Accessed 30 April 2022].

Bandukwala, N., 2022. How the Penis Works. [online] WebMD. Available at: <> [Accessed 30 April 2022].

Cleveland Clinic. 2020. Erection & Ejaculation: How Does It Work. [online] Available at: <> [Accessed 30 April 2022].

Montgomery KA. Sexual desire disorders. Psychiatry (Edgmont). 2008 Jun;5(6):50-5. PMID: 19727285; PMCID: PMC2695750.

Felson, S., 2021. Male Sexual Problems — the Basics. [online] WebMD. Available at: <,through%20masturbation%20or%20oral%20sex.> [Accessed 30 April 2022].

Laumann EO, Paik A, Rosen RC. Sexual dysfunction in the United States: prevalence and predictors. JAMA. 1999 Feb 10;281(6):537-44. doi: 10.1001/jama.281.6.537. Erratum in: JAMA 1999 Apr 7;281(13):1174. PMID: 10022110.