Download NAME: FEMOWEI EBIKABOERE BENITA COLLEGE: MEDICINE

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