Rarely do guys stop and think about how an erection actually comes about. It just does, or it doesn’t, so it's kind of irrelevant that the "machinery" behind it all stays hidden from view at all times. Yet, in point of fact, the machinery really is quite impressive when it's all broken down, and is something which can really be helpful to know if things quit functioning quite like they used to.
In short, an erection isn't a flip of a switch somewhere.
An erection is a step-by-step process between the brain, the nervous system, and the vascular system, and understanding the sequence helps a lot when it comes to determining where the process might have gone wrong, and why.
It All Starts in the Brain
The thing that most people would be a great deal surprised to find out is that an erection doesn't start in the penis. It starts in the brain. The brain plays an important role in erections. Anything from touching something that tickles you, to something that you see, to remembering something, or, if you're anything like me, to your imagination wandering into the exciting possibilities of the world - all of these things could kickstart it, and your body actually goes down two different routes to get there.
- You have psychogenic arousal, which is a thought, a memory, an image, or something that stimulates you on an emotional level and sends its command from the brain through the spinal column to the penis-supplying nerves.
- You also have reflexogenic arousal, which travels down a more direct line; if you stimulate yourself physically in the penis itself, the body has a reflex that can cause an erection to appear through the lowest spinal region, without any need to get yourself "worked up" at all mentally.
Whichever route is activated, it culminates in the same direction: a signal traveling down via the nervous system towards the penis's supply lines and vessels in order to set them in motion.
The Nervous System then Takes Over:
Once your erection is "turned on," it's controlled by your parasympathetic nervous system - pretty much your body is relaxed and doesn't do any function. Here is an extremely significant part to remember: this side of your nervous system can only do what it needs to do if your nervous system isn't dealing with a stressful situation. Which is really what causes erection problems when people are under stress or anxious: that stress is activating the other side of your nervous system - fight or flight- which is in opposition to the mechanisms that turn on an erection.
From the brain, a signal comes down the spine, then branches out into the pelvic nerves leading up into the penis. These nerve lines also come in direct contact with the prostate gland, and that is what causes erection problems with surgery, even if it goes off perfectly.
The Chemical Spark: Nitric Oxide
When that nerve signal reaches the penis, it triggers a chemical process and the release of a chemical – nitric oxide – in the erectile tissue, and this is what truly gets the ball rolling. Nitric oxide then causes a relaxed state of the smooth muscle in the walls of the corporal tissue of the penis (referred to as the corpus cavernosum). This relaxation of this smooth tissue results in the dilation or widening of the small arteries within this tissue, and therefore a greater than usual flow of blood in the tissue.
In fact, the very mechanisms on which the widely known ED medications, such as sildenafil, and tadalafil, are designed are based on this, and is why these drugs do not induce arousal but, rather, block a specific enzyme that would usually metabolize (destroy) nitric oxide and therefore allow it to work in stimulating blood flow for a bit longer.
But how does that increased blood flow actually result in erection?
It gets pumped in; the increased blood supply enters three spongy chambers in the penis (known as the corpus cavernosum x2 and corpus spongiosum, which surround the urethra) as the musculature relaxes and the arteries dilate. Blood fills and pushes the chambers out and firms the penis.
The Real Secret To Staying Firm: Entrapping the Blood
The erectile tissue engorges and bulges and creates pressure against a fibrous sleeve (tunica albuginea) that encloses it. This pressure closes down blood-letting veins that would otherwise drain the blood away. This is the veno-occlusive mechanism, and honestly it's the key player behind erection firmness.
It is the distinction between being somewhat filled and rock hard.
It is also a prime candidate for failure of the erection, as blood continues to flow in but can't exit through the properly compressed veins. Leaked blood means a loss of erection even when incoming blood flow was perfectly healthy. This failure has its own distinct title: veno-occlusive or venous leak dysfunction, which is just one type of purely physical erectile dysfunction.
And How It All Winds Down
Once stimulation ceases or an emission occurs, the process reverses. No more nitric oxide; relaxation disappears as the smooth muscles constrict again, the arteries narrow, the constricted veins open again, and blood flows back out.
Not a problem and a sign everything worked as a normal process of cyclical completion is that it takes an increased duration to regain rigidity; also known as the refractory period.
So What Does This Have to Do With Better Understanding ED?
In fact, given how many individual systems have to work together for you to get hard - nerve signals and then other signaling events in the penis, chemical signals that cause dilation and allow the blood into and then to be trapped - one glitch anywhere along this complicated assembly line can mean erectile dysfunction. This helps explain how many the causes of ED, and why knowing exactly which step in the ED assembly line to address actually makes a difference.
- Impaired nerve signaling: Often with conditions like diabetes, spinal injury, or following prostate surgery. The signals from the penis simply can’t be properly relayed.
- Impaired blood vessel function: Often linked to problems of cardiovascular health such as heart disease, hypertension, or smoking that constrict arteries.
- Poor blood retention: Venous leak occurs when blood enters the penis but can’t be retained effectively.
- Psychological inhibition: When your brain simply sends your penis signals that are counterproductive to full erectile function as part of a heightened stress/anxiety state.
This demonstrates why ED therapies target specific points on the ED chain; PDE5 inhibitors can work within the nitric oxide pipeline of signaling, but mechanical vacuum therapy is creating the actual blood fill and retention function, while some therapy for ED focuses on deactivating your body’s stress response to ensure a healthy erection.
The Bottom Line
In truth, an erection is really an extraordinary little chain reaction; arousal occurs in the brain, a message rapidly zips down the spinal cord, nitric oxide is released, smooth muscles relax, arteries open up to admit floodgates of blood, which then get stuck by compressed veins. Everything is reliant upon the steps that came before, which is the reason ED can originate from any one number of places and why the right treatment depends on what part of the sequence actually fails.
If you are suffering from the continued problem of E.D. This really is helpful to have information to discuss intelligently with a physician.
Where DirectMeds Fits into This
This background is incredibly useful but does not make a diagnosis - A cause such as venous leakage or a blood-vessel-related cause can appear similar to a cause of erectile dysfunction from nerve stimulation. It is critical to identify where in that chain the problem has originated, not by guesswork or by self-experimentation with "supplements" that could be causing more harm than good, but with medical advice.
DirectMeds is an AHPRA-registered online Australian telehealth service designed for this particular type of conversation. A brief, secure online questionnaire can be provided and the information reviewed by a licensed physician, who will conduct a consultation to pinpoint the failure in the sequence and devise a customized treatment plan, or prescribe any appropriate, TGA-approved medication that can be shipped discreetly to your home, foregoing the need for an in-office clinic appointment. Start Your ED Assessment with DirectMeds today!
Frequently Asked Questions for How Does an Erection Work:
How does an erection actually work (step by step)?
Your arousal will start in your brain and send an impulse down through your spinal cord to nerves in your penis, causing you to produce nitric oxide. This softens the muscles of the erectile tissue, widening the vessels of the arteries and drawing in blood. As the chambers fill up with blood, the erectile tissue presses up against nearby veins, shutting them closed, keeping the blood in place and erect.
What's the actual role of the nervous system in an erection?
The nervous system delivers the arousal signal from your brain to your penis and triggers your "rest and digest" (parasympathetic) nervous system, which is necessary for an erection. High stress levels or anxiety inhibit this system because you activate your "fight or flight" (sympathetic) system, the exact opposite of what you need.
What do ED medications do in this entire process?
Drugs such as sildenafil (Viagra) and tadalafil (Cialis) do not induce erection by themselves; they simply block the enzyme that would rapidly degrade your nitric oxide. As a result, there's more remaining, creating a more sustained process once erection begins.
Why is nitric oxide so important to erections?
Nitric oxide is the chemical trigger that starts the process. Once released in response to nerve stimulation, nitric oxide causes smooth muscle in erectile tissue to relax, which dilates arteries and allows blood to enter.
Why is an erection firm rather than just filling up and staying mushy?
Blood trapped inside the erectile tissue presses against its surrounding tissue sheath, which seals the blood-drainage veins. This trapped blood makes the erection rigid.
Can something go wrong anywhere along the line?
Trouble can occur at the level of nerve signaling (often a symptom of diabetes or nerve damage), at the level of the blood vessels (associated with heart disease), or at the level of the blood-trapping mechanism (which is called venous leak). Even stress and anxiety can mess with erections that might otherwise be physically functioning correctly.