Family Doctor Books
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Family
Doctor Books |
Preview of Understanding Sex
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The basic facts |
The male sex organs
The male sex organs consist of the penis and the
two testicles, contained in a bag of skin called the scrotum. The penis
becomes erect during sexual excitement, and allows penetration of the
female vagina, while the testicles produce the male sex hormone, testosterone,
and also sperm for fertilising the female egg, the ovum.
The penis
The shaft of the penis is made up of three long tubes
of spongy tissue – two identical ones that run on the top side of
the penis, each called a corpus cavernosum (plural corpora cavernosa),
and another, along the underside of the penis, called the corpus spongiosum.
The corpus spongiosum contains the urethra, which is the tube through
which urine and semen pass.
At the tip of the penis, the corpus spongiosum
expands to form the mushroom-shaped head of the penis called the glans.
This is covered by a layer of loose skin called the foreskin. This is
removed in circumcised males. A shallow groove lies between the glans
and shaft. A delicate fold of skin called the frenum connects the foreskin
to the glans, on the underside of the penis. A ring of little spots may
appear all round the bottom of the glans, in late adolescence and early
adulthood. These are called pearly papules and, although they may cause
concern in a young man and be mistaken for warts, they are natural and
harmless.
At the base of the penis, there are muscles which contract
rhythmically during orgasm, and also have a role to play in erection.
Male
reproductive system. |
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The testicles
The testicles in a male fetus develop in the abdomen,
and migrate down into the scrotum only during late pregnancy. Sometimes
this fails to happen, and a small operation is needed during childhood
to fix the testicles in the scrotum.
The testicles contain two types of
cells – one
for producing the male hormone testosterone, the other for sperm production.
Sperm passes from the testicles into a collection of tubes bunched together
to form the epididymis, which sits like a cap on the top back end of
each testicle. From there they pass into another tube called the vas
deferens. This is the tube that is cut and tied during a vasectomy, for
sterilisation.
The vas deferens leads to an area just behind the bladder
where it expands to form a storage area for sperm. Two small glands called
the seminal vesicles open into the vas deferens – these produce
seminal fluid which forms, together with sperm and fluid from the prostate,
the semen that is ejaculated during orgasm. Other glands also open near
this area, and they produce a clear fluid which is sometimes discharged
early on in sexual arousal and may contain enough sperm to cause pregnancy.
The
vas deferens then enters the prostate gland, which sits at the base of
the bladder, and there it joins the urethra, the tube that runs along
the penis, and that carries urine and semen.
There are two muscles that
support the testicles – the
dartos muscle causes shrinkage or relaxation of the scrotum, and the
cremaster lifts the testicle when it contracts. This muscle can sometimes
be overactive in a young man, causing an aching pain in the testicle
and groin during arousal and ejaculation. The treatment sometimes prescribed
is masturbation in a warm bath.
The male
sex organs.
Top right: cross-section of penis. Bottom right: cross-section
of testicle. |
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A man
may be sterilised by a vasectomy. |
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The female sex organs
The female organs are more complicated than the male
sex organs. Internally, in the lower abdomen, sit the uterus or womb,
the fallopian tubes and the left and right ovaries. The lower end of
the uterus forms the cervix, which juts into the top end of the vagina.
The vagina opens out into the external organs, which include the urethra,
the clitoris and the vulva.
The clitoris
The clitoris is in many ways a tiny penis. It has the
same basic structure of the three tubes along its length and, when a
woman is aroused, it also swells and becomes stiff. It is extremely sensitive
to touch, being packed with nerve endings, and although women become
sexually aroused by stimulation of the clitoris, movements that are too
heavy or clumsy can be painful.
The vulva
This consists of two layers of skin: the outer, thicker,
labia majora and the inner, more delicate, labia minora. These normally
lie against each other to seal the vaginal opening, but if they are parted
they reveal the vaginal opening. In a woman who has never had intercourse,
or used tampons, a thin membrane of skin called the hymen surrounds this
opening making it even smaller. Rarely the hymen may block the vagina
altogether, leading to the retention of blood when the girl starts to
menstruate. A small operation to cut the hymen is then needed. In other
women, the hymen is torn, and hymenal remnants lie around the opening,
which may give the vagina a slightly ragged appearance. Sitting in a
small bud of tissue just above the vaginal opening, inside the labia
minora, is the opening of the urethra, for the passage of urine.
At the
bottom of the vaginal opening are two glands, one on each side, called
Bartholin’s glands. These produce a fluid
which lubricates the vagina during intercourse. Sometimes they become
infected or swell to form a cyst, and antibiotics or a small operation
is necessary.
The vagina
The vagina is shaped like a tube and is normally around
10 centimetres in length. The lower part of the vagina, near the vulva,
is bounded by strong muscles which must be relaxed for comfortable penetration.
On the other hand, if they become too lax, perhaps after child-bearing,
sex may feel less pleasurable for both the man and the woman, and special
exercises need to be done to regain the muscle tone.
The cervix, or neck
of the womb, juts into the upper end. When a cervical or ‘pap’ smear
is done, the cervix is exposed with the help of an instrument called a
speculum, to open the vagina, and a small sample of tissue and mucus from
the cervix is gently removed and spread on to a slide to be viewed under
a microscope. Most women find direct pressure to the cervix uncomfortable,
as is repeated buffeting by the penis during sexual intercourse.
The walls
of the vagina are corrugated. When a woman is sexually aroused, the upper
two-thirds of the vagina increase in size to accommodate the penis fully.
Left:
the vulva or external female sex organs; right: the internal
female sex organs. |
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The uterus
The uterus or womb is triangular in shape, with the
tip pointing downwards, as the cervix, into the vagina. In most women,
the body of the uterus is bent slightly forward and flops over the bladder
in front of it. In other women it flops backwards – this is usually
of no consequence, except that the position of the cervix may then be
tricky to find for a smear! At each upper end, two short arms, called
the fallopian tubes, fan out. Finger-like tissue, at the ends of each
fallopian tube, encircle one ovary on each side. When a women is sterilised,
the fallopian tubes are cut and tied or clipped.
The uterus mainly consists
of muscle, and its function is to hold a developing fetus through pregnancy,
and then expel it by muscular contractions at labour. Its ability to
expand during pregnancy is remarkable, changing from a capacity of six
millilitres to four litres in nine months. It is normally only about
seven centimetres long.
Under the influence of hormones, the lining of
the uterus builds up each month. If a pregnancy does not occur, this
is shed as a woman’s period, or menstruation, at the end of the cycle of
build up, on average every 28 days. Women’s monthly cycles vary
a great deal, however, and many women do not have completely regular
periods.
If a pregnancy does occur, the lining of the uterus
continues to build up, in preparation for the fetus, which will fix itself
onto the lining and start to develop. A missed period is therefore often
the first sign a woman has that she may be pregnant.
Female
sterilisation: the fallopian tube is tied (left) or clipped (right). |
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The ovaries
The ovaries contain the eggs, or ova. Each egg is surrounded
by a cluster of cells. Each month one egg ‘ripens’, and the
cells around it grow until, at ovulation, the egg breaks through the
surface of the ovary and gets taken up by the finger projections of the
fallopian tube. It travels down the tube, where, if there are sperm,
fertilisation or conception takes place. Ovulation normally takes place
14 days after the start of a woman’s period.
What happens during lovemaking?
Foreplay or loveplay is the time that couples spend
kissing, cuddling and physically stimulating each other so that they
are both ready for intercourse. People vary a lot in the amount of foreplay
they like to get them ‘in the mood’ for sex. Most couples develop
a ‘routine’ that works for both of them, but it is fun occasionally
to change this routine, so that intercourse is interspersed with periods
of foreplay or oral sex, and new positions are tried. There are no set
patterns about what goes on during lovemaking, and no rules that kissing
leads to foreplay, which leads to intercourse – making it up as
you go along is part of the pleasure.
Kissing (on the lips, body or genitals),
cuddling, gentle biting and stroking each other help a couple relax and
feel physically close. As they become more aroused, they may start to
explore each other’s
bodies. Women usually enjoy having their breasts and nipples gently stroked
or kissed, and their thighs caressed. They may enjoy having a finger
or two gently introduced into the vagina. The clitoris is very sensitive,
and it may be painful to touch if the woman is not sufficiently aroused,
or if the touch is too heavy or rough. Most women enjoy having the shaft
(or side) of the clitoris gently and repetitively stroked or patted,
and many women find oral sex very exciting.
Men enjoy having the shaft
and head of their penis held and stroked repetitively, or kissed, licked
and sucked (like an ice cream). They vary in how tightly or loosely they
like to be gripped. Some men also enjoy it if their testicles are touched
or held, or the buttocks and thighs caressed. Men’s nipples are less sensitive than
women’s, but some men like to have them stimulated as well.
When
a couple feel ready for intercourse, the penis is inserted into the vagina
and the couple move together, rhythmically, so that their sexual pleasure
is increased. For men, the change from stimulation by hand to intercourse
usually greatly increases their sexual arousal, but this is not always
the case for women. In a loving relationship, women find penetration
deeply emotionally satisfying, but positions adopted in intercourse do
not always allow for adequate clitoral stimulation. Less experienced
women, and women who do not have sex often, may also find penetration
uncomfortable, even if they are aroused. Couples need to experiment with
various positions to see which ones they can adapt for their own lovemaking.
The clitoris
is very sensitive and may be painful if the touch is too heavy
or rough. |
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Positions for intercourse
Many books provide helpful instructions on the seemingly
end-less positions a couple can adopt for sex, but they are mostly variations
of four basic positions, and sometimes require unrealistic degrees of
athleticism!
- The missionary position: In this position
the man rolls on top of the woman with his legs together and inserts
his penis into her vagina. The woman lies on her back with her thighs
wide enough apart to allow comfortable penetration. The advantage
of this position is that the couple can kiss and stroke each other’s
faces, the man can stroke the woman’s breasts, but clitoral
stimulation may not be adequate unless the man specifically rubs
his penis against the clitoris. Variations of this position include
the woman bringing her knees up against her chest, or the man kneeling
on the floor with the woman lying half on the bed, with her legs
around his waist.
- Woman on top: The man lies down on his
back and the woman lowers herself onto his penis, sitting astride
him. This position is popular with some women who find they are more
in charge of the frequency and depth of penetration, and can achieve
good clitoral stimulation. It is also a good position during pregnancy.
The woman may kneel over the man, leaning forward or actually sit
on top of him as on a low chair, with her legs in front of her. The
couple face each other and the man can stroke the woman’s breasts
or clitoris. Variations include both partners sitting up cross-legged,
the woman with her legs wrapped around the man’s waist.
- Side by side: Both partners lie on their
side facing each other, the woman draws her uppermost leg up, and
the man inserts his penis this way. This position allows for prolonged
intercourse because both partners are lying down. The couple can
stimulate each others’ genitals or nipples.
- Penetration from behind: Usually the woman
kneels on all fours on the bed and the man penetrates her, pushing
his body against her buttocks. The man can stroke his partner’s
back, and play with her breasts and clitoris. The drawback is that
partners do not face each other in this position. Variations include
a sitting position (the woman sitting on top of the man but facing
away from him), or standing up leaning over a bed or table for support.
What happens to the body during intercourse?
When a man is sexually aroused, his penis becomes erect.
Blood flow to the penis increases, and at the same time blood flow out
of the penis shuts down. The spongy tissue in the two corpora cavernosa
and the corpus spongiosum therefore fill with blood and become stiff
and hard. The small muscles at the base of the penis also rhythmically
contract to maintain the erection.
As stimulation increases, sexual excitement
increases and the man becomes aware that orgasm is approaching. He reaches
a stage of ‘ejaculatory inevitability’, when ejaculation occurs
within one to three seconds. Muscles in the testicles and the vas deferens
contract, ready to pump the semen down the urethra. The passage of urine
into the urethra is blocked off. Fluid from the prostate gland and the
seminal vesicles mixes with the sperm to form semen, which collects at
the top of the urethra. When orgasm arrives, this is propelled down the
urethra by muscular action and spurts out of the penis.
After orgasm, there
is a period in which a man becomes unresponsive to sexual stimulation.
This is called the refractory period and varies from person to person,
from minutes to hours. The penis loses its rigidity, the rest of the body
relaxes, and often there is a strong desire to sleep.
In a woman, sexual
arousal causes swelling of the clitoris and vulva, and increased lubrication.
The whole ‘introitus’,
as the opening of the vagina is called, responds in this way to make
penile entry easy and pleasurable for the woman. The uterus also increases
in size and rises, pulling the cervix out of the way of the penis. The
upper part of the vagina balloons. During orgasm the muscles of the vagina
and uterus contract rhythmically, and some women also ejaculate a small
amount of fluid from the urethra, which is not urine. This is thought
to be the female equivalent of male ejaculation. Women do not strictly
have a refractory period, and some women are able to have several orgasms
in a row.
The penis,
on the left, in resting position and, on the right, during an
erection. |
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Male and female sexuality
It is clear from the above descriptions that physical
changes during sexual excitement facilitate intercourse in both sexes.
Many sexual problems arise because of a couple’s different rates
and patterns of response, or ability to respond at all. If a man is unable
to become aroused and erect, his partner feels sexually frustrated, unattractive
and rejected. If a woman is sexually disinterested, she may avoid sex,
or complain that it is painful because she is not sufficiently aroused.
Her partner may be at a loss to excite her and feel like a failure.
It
has been said that men get turned on like light bulbs – instantaneously – while women heat up slowly like irons.
Amusing statements like this oversimplify the complexity and variety
in human sexual relations – and may be hurtful to the many men who
find they are not like light bulbs! Indeed there are many couples in
which it is the woman who has the higher sex drive.
There have been many
famous sex surveys, notably the ones conducted by Masters and Johnson,
Kinsey and Hite. One common finding is that men reach the peak of sexual
activity early on in life, usually in their teens, when they average
five orgasms a week. By their forties this figure falls to two or three
orgasms a week and continues to decline with increasing age.
In contrast,
women do not seem to reach their peak till their late twenties or thirties
onwards, with a much steadier pattern of increasing and decreasing sexual
activity, with increasing age, than seen in men. Women also have more
complicated sexual lives, with the issues of menstruation, fertility,
pregnancy and menopause playing important roles.
All surveys reveal that
despite a ‘general pattern’ many
individuals are very different from the average – and so, just as
there are men who have not ejaculated for years, there are women who
become aroused many times a day. Similarly there are men who ejaculate
several times a day, and women who have only been aroused several times
in their lives. The truth is, of course, that conforming to a ‘general
pattern’ matters much less than being comfortable with one’s
own sexuality.
People’s religious and cultural beliefs are hugely
important in determining their attitudes to sex, and to what they feel
is acceptable behaviour or not. Even if mentally they know that an activity
(such as masturbation) is harmless, emotionally they may still feel guilt
and regret.
A generation or so ago it was assumed that men were
naturally more interested in sex than women and, as a result, overt behaviour
such as masturbation, initiating sexual liaisons or even paying for sex
was tolerated more in men than in women. The tide of feminism, and the
recognition of women’s rights and issues, have meant that the taboo
around female sexuality has been lifted, and it is clear that sex is
as important to women as it is to men. Women are now more able to admit
to sexual appetites, and to masturbation and fantasy. In 1981 one survey
found that 73 per cent of women interviewed said they had masturbated
by the age of 20. The same researchers had done a similar survey 15 years
earlier, and in 1966 the figure was only 46 per cent. Are more women
masturbating now, or are they simply more able to talk about it?
Female
sex organs before (left) and during (right) sexual arousal. |
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How often do other couples make love?
Most surveys have found that average frequencies of
two or three times a week are common for most age groups. In general,
however, sexual activity is higher in young couples, and couples who
live together and are not married, and tends to decline after two years
in both married and co-habiting couples. In some religions and cultures,
sex during a wo-man’s period is forbidden. In most couples, events
such as pregnancy, child-rearing, family problems or work stresses alter
sexual frequency. One well-known agony aunt claims that if, in the first
five years of being together, a couple put a penny in a jar each time
they made love, then after five years took a penny out each time they
made love, the jar would never empty, even if they were together for
the rest of their lives!
Is there more than one type of orgasm for a woman?
There has been much debate about the different types
of orgasm a woman can have, with a suggestion that orgasms achieved through
vaginal penetration only are more ‘matured’ than clitoral orgasms.
Surveys have revealed, however, that most women are unable to have an
orgasm without some clitoral stimulation before or during intercourse.
It now appears that the female orgasm originates from the clitoris whether
it is directly stimulated (by stroking or kissing) or indirectly stimulated
(by penile thrusting).
Another controversy surrounds the existence or
non-existence of the ‘G-spot’ – an area located in the
vagina just behind the clitoris. Some women find stimulation of this
area highly arousing. It is thought that pressure on this area stimulates
either the clitoris or the urethra indirectly, and is therefore pleasurable
and exciting.
All these issues aside, the truth is that female sexual
arousal is more complex and less obvious than the male response and most
women take time to learn what their bodies like, and what is possible
in conventional sexual positions and with each new partner. Most couples,
if they are willing to experiment and communicate, will find a pattern
of behaviour that satisfies them both.
Some
women find stimulation of the ‘G-spot’ highly arousing. |
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What can one do with mismatched sexual drives?
Few couples have perfectly matched sex drives and it
seems unreasonable to expect one partner to feel as sexy and passionate
as the other every time. This may have appeared to have been the case
early on in the relationship, but most couples settle down to a frequency
that takes into account their own sex drives, work, children, etc. If
sex drives are really mismatched, it is helpful to talk about this fully
and admit to this without any suggestion of failure or abnormality in
either partner. In any sexual relationship the emphasis should be less
on achieving orgasm and more on the closeness and communication that
sex allows. Cuddling and stroking each other can be just as pleasurable
as intercourse, and masturbation either by the partner or alone can take
the edge off any frustration for the more active partner. If there is
a serious difference in the amount or degree of physical intimacy each
partner wants, then they may have to reassess their relationship to see
if other positive factors make it worth maintaining.
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KEY POINTS
- Physical changes during sexual arousal facilitate
intercourse in most women
- Partners may differ in how quickly they become
aroused
- Partners may differ in how often they want to
make love
- Closeness and intimacy can be as fulfilling as
intercourse
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