Erection causes

The penis has two corpora cavernosa, which have many interconnected sinuses that fiU with blood to produce an erection. The penis also has one corpus spongiosum, which surrounds the urethra and forms the glans penis. Acetylcholine works with other neurotransmitters (i.e., cyclic guanylate monophosphate, cyclic adenosine monophosphate, vasoactive intestinal polypeptide) to produce penile arterial vasodilation and ultimately an erection. Causes of organic ED include diseases that compromise vascular flow to the corpora cavernosum (e.g., peripheral vascular disease, arteriosclerosis, essential hypertension), impair nerve conduction to the brain (e.g., spinal cord injury, stroke), and are associated with hypogonadism (e.g., prostate or testicular cancer, hypothalamic or pituitary disorders). 

The iliopsoas remains in constant activity in the erect posture and prevents hyperextension ofthe hipjoint in a standing subjeet. An increase in lumbar lordosis while standing erect causes increased activity of the psoas and low back instability and dysfunction. 

The other cause of constmction problems is the introduction of badly chosen, or even unauthorized, changes during constmction in order to expedite the work. Any changes in details, material specifications, or erection procedure must be given careful consideration by both the builder and silo designer. 

Damage to prefabrication primers or even the whole film system can be caused on transport or on erection, leaving for example, bare edges. Good supervision is necessary to ensure that defective areas are conscientiously touched-up before applying further paint films. It has been recommended to disregard the coat of prefabrication primer when deciding the number of coats to be specified. ... 

MISCELLANEOUS ANTIDEPRESSANTS. An uncommon but potentially serious adverse reaction of trazodone is priapism (a persistent erection of die penis). If not treated within a few hours, priapism can result in impotence The nurse instructs the patient to report any prolonged or inappropriate penile erection. Use of the drug is discontinued immediately and the primary care provider notified. Injection of a-adrenergic stimulants (eg, norepinephrine) may be helpful in treating priapism. In some cases, surgical intervention may be required. Venlafaxine may cause an increase in die blood pressure. A sustained increase in die blood pressure may indicate that die dosage of venlafaxine needs to be decreased. 

Sympathetic and parasympathetic nerves innervate the penis. In the flaccid state, OC2-adrenergic receptors mediate tonic contraction of the arterial and corporal smooth muscles. This maintains high penile arterial resistance and a balance exists between blood flow into and out of the corpora. With sexual stimulation, nerve impulses from the brain travel down the spinal cord to the thoracolumbar ganglia.3 A decrease in sympathetic tone and an increase in parasympathetic activity then occurs, causing a net increase in blood flow into the erectile tissue. Erections may also occur as a result of a sacral nerve reflex arc while patients are sleeping (nocturnal erections). 

Psychogenic dysfunction occurs if a patient does not respond to psychic arousal. It occurs in up to 30% of all cases of ED. Common causes include performance anxiety, strained relationships, lack of sexual arousability, and overt psychiatric disorders such as depression and schizophrenia.5 It is postulated that the anxious or nervous man will have excessive stimulation of the sympathetic system, leading to smooth muscle contraction of arterioles and vascular spaces within erectile tissue.6 O Many patients may initially have organic dysfunction, but develop a psychogenic component as they try to cope with their inability to achieve an erection. It has been estimated that up to 80% of ED cases have an organic cause, with many having a psychogenic component as well.1... 

Clinical features Priapism is defined as a painful and unwanted erection, which is classified as stuttering (less than 3 hours), often multiple prolonged (more than 3 hours). Up to 89% of males with SCD will have at least one episode by age 20. The mean age of the initial episode is 12 years of age. Repeated episodes can cause fibrosis and impotence. 

Signs The first symptoms consist of darker green streaks in a pattern of "dots" and "dashes" ("Morse code" streaking) on the lower portion of the midrib. Later, the streaks appear on the secondary veins of the leaf and then on the leaf blade. Suckers that develop after infection are usually severely stunted, which causes the leaves at the top of the stem to become bunched. Leaves are usually short, stiff, erect, and more narrow than normal. Severely infected banana plants usually will not fruit. If the plant does bear fruit, it will likely be distorted and twisted. 

Intracavernosal alprostadil has been used successfully in combination with VEDs or vasoactive agents (e.g., papaverine, phentolamine, atropine) that act by different mechanisms. Phosphodiesterase inhibitors should not be added to intracavernosal alprostadil because the combination can cause prolonged erections and priapism. 

Then Cecile found employment in the office of one of those new factories which had recently been erected over there beyond the town. This step had been the cause of the first disagreement between her mother and herself. 

But not everything that norepinephrine and acetylcholine do is opposed. In one case, they cooperate. Acetylcholine stimulates penile erection by increasing blood flow to that organ. Norepinephrine controls ejaculation. In still other cases, the pharmacology of these neurotransmitters is unique. For example, acetylcholine induces urination by causing the bladder to constrict. Acetylcholine also induces secretion of saliva and tears. Norepinephrine has nothing to do with these functions. 

Figure 19.17 The biochemistiy and physiology responsible for penile erection. Sexual activity itself begins with a state of arousal that leads to erection. Arousal results in part from stimulation of the sense organs. The hypothalamus coordinates the sensations and activates the autonomic nervous system. Sensory nerves from the skin of the penis and other erogenous zones stimulate the parasympathetic system. This activates nitric oxide synthase and the resultant nitric oxide, via cyclic GMP, causes vasodilation of the arterioles. This increases blood flow through the corpora cavernosa which then expands producing an erection. Pheromones secreted by the female can stimulate the odour detecting system in the nasal cavity of the male (Chapter 12 and see above). Stress, however, activates the sympathetic system releases cyclic AMP which can result in vasoconstriction of the arterioles. Other factors that can interfere with an erection are physical fatigue and alcohol.

Trazodone may cause priapism and enhance libido, and it prolongs nocturnal erections. This drug has been used both orally and by intracavemosal injection. It can be used alone or in combination with yohimbine. Overall, trazodone has not been as effective in treating ED as other available agents. However, it may be an option for selected patients, particularly those with performance anxiety or low libido. 

Merlob, P. and Livne, P.M. (1989) Incidence, possible causes and followup of idiopathic prolonged penile erection in the newborn. / Urol 141 1410-1412. 

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