Because adequate arterial supply is critical for erection, any disorder that impairs blood flow may be implicated in the etiology of erectile failure. Most of the medical disorders associated with erectile dysfunction appear to affect the arterial system. Some disorders may interfere with the corporal veno-occlusive mechanism and result in failure to trap blood within the penis, or produce leakage such that an erection cannot be maintained or is easily lost.
Ultrasound with Doppler imaging (ultrasound plus evaluation of blood flow in the arteries and veins) can provide additional information about blood flow of the penis and may help in the evaluation of patients prior to surgical intervention. This study is typically performed after the injection of a chemical that causes the arteries to open up, a vasodilator (prostaglandin E1), into the corpora cavernosa in order to cause dilation of blood vessels and promote blood flow into the penis. The rate of blood flow into the penis can be measured along with an evaluation of problems with compression of the veins.
When stimulated by the nerves, the spongy tissue arranges itself in such a way that more blood can be stored in the penis. The veins running through the outer sheath of the penis then compress which stops the blood from leaving the penis. As the blood is stopped from flowing out, the penis fills with blood and stretches within the outer casing, giving an erection.
Causes of impotence are many and include heart disease, high cholesterol, high blood pressure, obesity, metabolic syndrome, Parkinson's disease, Peyronie's disease, substance abuse, sleep disorders, BPH treatments, relationship problems, blood vessel diseases (such as peripheral vascular disease and others), systemic disease, hormonal imbalance, and medications (such as blood pressure and heart medications).
Cosgrove et al reported a higher rate of sexual dysfunction in veterans with posttraumatic stress disorder (PTSD) than in veterans who did not develop this problem.  The domains on the International Index of Erectile Function (IIEF) questionnaire that demonstrated the most change included overall sexual satisfaction and erectile function. [43, 44] Men with PTSD should be evaluated and treated if they have sexual dysfunction.
After the history, physical examination, and laboratory testing, a clinical impression can be obtained of a primarily psychogenic, organic, or mixed etiology for erectile dysfunction. Patients with primary or associated psychogenic factors may be offered further psychologic evaluation, and patients with endocrine abnormalities may be referred to an endocrinologist to evaluate the possibility of a pituitary lesion or hypogonadism. Unless previously diagnosed, suspicion of neurologic deficit may be further assessed by complete neurologic evaluation. No further diagnostic tests appear necessary for those patients who favor noninvasive treatment (e.g., vacuum constrictive devices, or pharmacologic injection therapy). Patients who do not respond satisfactorily to these noninvasive treatments may be candidates for penile implant surgery or further diagnostic testing for possible additional invasive therapies.
The neurologic pathways required for erection originate in the cerebral cortex where visual, auditory, and psychic stimuli are processed, and in the pudenal nerve, an afferent nerve that transmits tactile sensations from the genitals to the sacral segments of the spinal cord and cortex. Efferent signals from the spinal cord pass along the pelvic parasympathetic nerves and dilate the corporal vessels. The specific neurotransmitters have not been fully defined; acetylcholine, and perhaps vasoactive intestinal peptide, appears to be important. There are many causes of neurogenic impotence. Anything that disrupts neural pathways or blocks neurochemical transmission will have an adverse effect on erection. Psychologic factors probably interfere with erection by inhibiting corticosacral efferent pathways.
I'd recommend the second option. In any long-term relationship, there will come a time when you flirt a little too much. Technology makes those little transgressions seem much more major because there's digital proof. (I'm guessing that you would never have flashed him in the real world. Would you?) Maybe you should just learn from your experience and save your boyfriend the drama. Understand that you made a mistake, and keep your breasts to yourself.
In a randomized double-blind, parallel, placebo-controlled trial, sildenafil plus testosterone was not superior to sildenafil plus placebo in improving erectile function in men with ED and low testosterone levels.  The objective of the study was to determine whether the addition of testosterone to sildenafil therapy improves erectile response in men with ED and low testosterone levels.
It is common for a healthy older man to still want sex and be able to have sex within appropriate limitations. Understanding what is normal in older age is important to avoid frustration and concern. Older men and their partners often value being able to continue sexual activity and there is no age where the man is ‘too old’ to think about getting help with his erection or other sexual problems.
Drugs for treating impotence can be taken orally or injected directly into the penis or inserted into the urethra at the tip of the penis. Oral testosterone can reduce impotence in some men with low levels of natural testosterone. Patients also have claimed effectiveness of other oral drugs--including yohimbine hydrochloride, dopamine and serotonin agonists, and trazodone--but no scientific studies have proved the effectiveness of these drugs in relieving impotence. Some observed improvements following their use may be examples of the placebo effect, that is, a change that results simply from the patient's believing that an improvement will occur.
Healthy lifestyle minimizes risk of ED. Erection depends on blood flow through the penis. Anything that impairs it increases ED risk: smoking, diabetes, high cholesterol, high blood pressure, heart disease, being overweight, sedentary lifestyle, more than two alcoholic drinks a day, and fewer than five daily servings of fruits and vegetables. Avoiding these risk factors does not prevent post-50 erection changes, but it preserves erection function and helps prevent ED.
The Massachusetts Male Aging Study (MMAS) documented an inverse correlation between ED risk and high-density lipoprotein (HDL) cholesterol levels but did not identify any effect from elevated total cholesterol levels.  Another study involving male subjects aged 45-54 years found a correlation with abnormal HDL cholesterol levels but also found a correlation with elevated total cholesterol levels. The MMAS included a preponderance of older men.
You may already know that lots of hard drugs — like cocaine, heroin, or Oxycontin — can cause sexual problems (though, quite frankly, if you're on cocaine, heroin, or Oxycontin, you have many more pressing concerns to deal with than getting dirrrty). But did you know that sometimes, even pot can inhibit erections? And you thought weed was just a harmless way to enjoy the musical stylings of Pink Floyd. Who knew it could actually mess with one's own pink floyd?
An analysis of 14 studies involving more than 90,000 patients with ED confirmed the relation between ED and an increased risk of cardiovascular events and mortality.  Compared with patients without ED, those with ED had a 44% increased risk of cardiovascular events, a 25% increased risk of all-cause mortality, a 62% increased risk of MI, and a 39% increased risk of cerebrovascular events. Treatment of ED, either through lifestyle interventions or by pharmacologic means, may improve prognosis and reduce risk.
Smoking damages blood vessels, inhibiting blood flow throughout the body ... and I mean throughout the body. While studies have found that men with erectile problems only make up 20 percent of the general population, 40 percent of men with erectile problems are smokers. And a 2011 study of a group of male smokers with erectile problems found that 75 percent of them saw those erectile problems disappear after they quit.
Medical conditions, such as hypertension, diabetes mellitus, and cardiovascular disease (CVD), and psychological conditions, such as depression and anxiety, also contribute to sexual dysfunction in middle-aged or elderly men. CVD and hypertension cause a narrowing and hardening of the arteries, leading to reduced blood flow to the corporal bodies, which is essential for achieving an erection. Diabetes is a common aetiology of sexual dysfunction, because it can affect both the blood vessels and the nerves that supply the penis. Men with diabetes are four times more likely to experience ED, and on average, experience ED 15 years earlier than men without diabetes.7 Obesity is also correlated to the development of several types of dysfunction, including a decrease in sex drive and an increase in episodes of ED.8
My boyfriend has a hard time getting and staying hard. It's obviously a difficult situation to talk about, but he says he feels pressure when he's with me (versus previous random hookups he wasn't invested in), so he psyches himself out. When we do have sex, I'm almost always really satisfied and I care a lot about him, both things I express in and outside of the bedroom. But the situation seems to be only getting worse. We've stopped having sex during the week because our busy lives mean we don't have an hour or more to devote to sex (which is sometimes what it takes), or we can't have sex at all because of what he's experiencing. I'm afraid this is going to continue to get worse, not only sexually but emotionally in our relationship. How can I help him fix this, and reassure him in the meantime that I care about him and want to support him?
Erections are more complicated than you think. Your brain, nerves, heart, blood vessels, and a whole lot of hormones have to work together perfectly or nothing happens. It’s a lot to ask, and sometimes things break down. And while ED happens to most guys at some point in their lives, erectile dysfunction isn’t something you can just ignore and hope it goes away.