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NAME: FEMOWEI EBIKABOERE BENITA COLLEGE: MEDICINE AND HEALTH SCIENCES DEPARTMENT: NURSING SCIENCE MATRIC NO: 13/MHS02/018 COURSE: REPRODUCTIVE PHYSIOLOGY COURSE CODE: PHS 212 ASSIGNMENT Write short note on erection and coitus PHYSIOLOGY OF ERECTION An erection (clinically: penile erection or penile tumescence) is a physiological phenomenon in which the penis becomes firmer, engorged and enlarged. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is often associated with sexual arousal or sexual attraction, although erections can also be spontaneous. The shape, angle and direction of an erection vary considerably in humans. Erection is also a neurovascular event subject to psychological and hormonal modulation. Upon sexual stimulation, nerve impulses release neurotransmitters from the cavernous nerve terminals and relaxing factors from the endothelial cells in the penis resulting in; (a) relaxation of smooth muscle in the arteries and arterioles supplying the erectile tissue. As a result, there is a several-fold increase in blood flow. Concomitantly, there is(b) relaxation of the sinusoidal smooth muscle within the paired corporeal bodies, facilitating rapid filling and expansion of the sinusoidal system. As a result, (c) venous plexuses located between the sinusoids and rigid tunic covering the penis are compressed resulting in almost total occlusion of venous outflow. These events effectively trap the blood within the corpora cavernosa and raise the penis from flaccid to erect position; in doing so, an intracavernous pressure of 100 mm Hg (full erection phase) is achieved. Both masturbation and sexual intercourse trigger the bulbocavernosus reflex, which causes the ischiocavernosus muscles to forcefully compress the blood-filled corpora cavernosa. CLINICAL PHYSIOLOGY An erection problem occurs when a man cannot get or keep an erection that is firm enough for intercourse. Erection problems cannot affect the sex drive of an individual. Almost all adult men have trouble getting or keeping an erection at one time or another. Often the problem goes away with a little or no treatment. But for some men, it can be an ongoing problem. This is called erectile dysfunction (ED). ERECTILE DYSFUNCTION Erectile dysfunction is defined as the inability to achieve and maintain an erection sufficient for satisfactory sexual intercourse. It is estimated to affect 20 to 30 million men in the US. It may result from impairment of one or more factors: psychological, neurologic, hormonal, arterial, and venous. More recently it has become clear that, in many cases, erection dysfunction can be a “silent marker” for the later development of cardiovascular diseases. CAUSES OF ERECTILE DYSFUNCTION Erectile dysfunction can be classified as psychogenic, organic (neurogenic, hormonal, arterial, venous or cavernosal and drug-induced), and mixed psychogenic and organic. The last is the most common. Common causes of psychogenic erectile dysfunction include performance anxiety, strained relationship, lack of sexual arousability, and overt psychiatric disorders such as depression and schizophrenia. Neurologic disorders such as Parkinson's and Alzheimer's diseases, stroke, and cerebral trauma often cause erectile dysfunction by decreasing libido or causing inability to initiate the erectile process. In men with spinal cord injuries, the degree of erectile function depends largely on the nature, location and extent of the lesion. Hormonally, androgen deficiency results in a decrease in nocturnal erections and decreases libido. However, erection in response to visual sexual stimulation is preserved in men with hypogonadism, suggesting that androgen is not essential for erection. Hyperprolactinemia of any cause results in both reproductive and sexual dysfunction due to the inhibitory action of prolactin on gonadotropin-releasing hormone secretion, resulting in hypo gonadotropic hypogonadism. PHYSIOLOGY OF COITUS Coitus is defined as the coming together of male and female sex organs, sometimes in the act of sexual procreation; the male’s penis is inserted into the female’s vagina, usually until orgasm and ejaculation of semen occurs. Coitus is also known as the male sexual act which can be divided into erection, lubrication and ejaculation. After the penis has been erected, the female sexual organs, rather than the male, supply most of the lubrication of coitus; after lubrication is the climax of the male sexual act (ejaculation) occurs. This process is referred to the process of coitus. Coitus interuptus, also known as the rejected sexual intercourse, withdrawal or pull-out method, is the method of birth control in which a man, during intercourse, withdraws his penis from a woman’s vagina prior to orgasm (and ejaculation), and then direct the vagina in an effort to avoid insemination. The method of contraception, widely used for at least two millennia, is still in use today. This method was used by an estimated 38 million couples in 1991. Coitus interuptus does not protect against sexually transmitted diseases (STIs/STDs). EFFECTS Like many methods of birth control, reliable effect is achieved only by correct and consistent use. Observation failure rates of withdrawal vary depending on the population being studied: studies have found actual failure rates of 15-28% per year. In comparison, the pill has an actual use failure rate of 2-8 which the intrauterine device (IUD) has an actual use failure rate 0.8%. it has been suggested that the pre-ejaculate (“Cowper’s fluid”) emitted by the penis prior to ejaculation normally contains spermatozoa (sperm cells), which would compromise the effectiveness of the method. However several small studies have failed to find any viable sperm in the fluid. ADVANTAGES The advantage of coitus interruptus is that it can be used by people who have objections to do not have access to other forms of contraception. Some men prefer it so that they can have a full experience and really able to “feel” their partner.it has no monetary cost, requires no artificial devices, have no physical side effects, can be practiced without a prescription or medical consultation, and provide no barriers to stimulate. DISADVANTAGES The method may be difficult for some couples to use. The interruptus of interruption of intercourse may leave some couples sexually frustrated or dissatisfied. REFERENCE Kieth L. Moore and T.V. N Persuad (2008). The developing human: clinical oriented embryology (8th ED) Inderbir Singh (2006). Test book of human neuroanatomy (7th ED) jaypee brothers medical publisher medical publisher LTD Oxford dictionary Wikipedia