Human sexual response cycle
Encyclopedia
The human sexual response cycle is a four-stage model of physiological responses during sexual stimulation
. These phases, in order of their occurrence, are the excitement phase, plateau phase, orgasmic phase, and resolution phase. The term was coined by William H. Masters and Virginia E. Johnson
in their 1966 book Human Sexual Response.
, such as kiss
ing, petting, or viewing erotic images, that lead to sexual arousal
. During the excitement stage, the body prepares for coitus, or sexual intercourse
, in the plateau phase.
. An erection
of the nipple
s, especially upon direct stimulation, occurred in nearly all females and approximately 60% of males. Vasocongestion
of the skin, commonly referred to as the sex flush, will occur in approximately 50-75% of females and 25% of males. The sex flush tends to occur more often under warmer conditions and may not appear at all under cooler temperatures.
During the female sex flush, pinkish spots develop under the breasts, then spread to the breasts, torso, face, hands, soles of the feet, and possibly over the entire body. Vasocongestion is also responsible for the darkening of the clitoris and the walls of the vagina during sexual arousal.
During the male sex flush, the coloration of the skin develops less consistently than in the female, but typically starts with the epigastrium (upper abdomen), spreads across the chest, then continues to the neck, face, forehead, back, and sometimes, shoulders and forearms.
The sex flush typically disappears soon after orgasm occurs, but this may take up to two hours or so, and sometimes, intense sweating will occur simultaneously. The flush usually diminishes in reverse of which it appeared.
An increase in muscle tone (myotonia
) of certain muscle groups, occurring voluntarily and involuntarily, begins during this phase among both sexes. Also, the external anal sphincter may contract randomly upon contact (or later during orgasm
without contact).
Sexual excitement in both sexes can be strongly modified by subjective psychological factors. Neuro-psychoanalyst Mark Blechner calls this "the Lady Chatterley phenomenon" based on the passage in the D. H. Lawrence
novel Lady Chatterley's Lover
in which Lady Chatterley is first completely unexcited during intercourse and ridicules the sex act, and then, shortly thereafter, becomes intensely sexually excited.
becomes partially erect, often after only a few seconds of erotic stimulation. The erection
may be partially lost and regained repeatedly during an extended excitement phase. Both testicles become drawn upward toward the perineum
, notably in circumcised
males where less skin is available to accommodate the erection. Also, the scrotum
can tense and thicken during the erection process.
become flatter, thinner, and rise upwards and outwards in nulliparous women (those who have not given birth). In parous women (those who have given birth), they may increase two or threefold in size. The labia minora
may increase in size and may protrude from the labia majora, depending on the size they are in a relaxed state. The clitoral glans
becomes tumescent
, or swollen, like the glans
of the penis and vaginal lubrication
is produced by the vasocongestion of the vaginal walls. They darken in color and become smoother than normal. Also, the uterus
elevates, more vertically as time passes, and the inner two-thirds of the vagina
expand, usually a total of 7 to 10 cm.
. The phase is characterised by an increased circulation and heart rate in both sexes, increased sexual pleasure with increased stimulation, and further increased muscle tension. Also, respiration continues at an elevated level.
contracts (so as to prevent urine
from mixing with semen
, and guard against retrograde ejaculation
) and muscles at the base of the penis
begin a steady rhythmic contraction. Males may start to secrete seminal fluid or pre-ejaculatory fluid and the testicles rise closer to the body.
and labia further increase in size, the clitoris
withdraws slightly and the Bartholin glands produce further lubrication
. The tissues of the outer third of the vagina swell considerably, and the pubococcygeus muscle
tightens, reducing the diameter of the opening of the vagina and creating what Masters and Johnson refer to as the orgasmic platform
. For those who never achieve orgasm, this is the peak of sexual excitement. Both men and women may also begin to vocalize involuntarily at this stage.
Prolonged time in the plateau phase without progression to the orgasmic phase may result in frustration if continued for too long (see orgasm control
).
and vagina
l contractions. Orgasms are often associated with other involuntary actions, including vocalizations and muscular spasms in other areas of the body, and a generally euphoric sensation. Heart rate is increased even further.
. Each ejection is associated with a wave of sexual pleasure, especially in the penis and loins. Other sensations may be felt strongly among the lower spine, or lower back. The first and second convulsions are usually the most intense in sensation, and produce the greatest quantity of semen. Thereafter, each contraction is associated with a diminishing volume of semen and a milder wave of pleasure.
up the vaginal walls into the uterus.
Men and women may or may not experience a refractory period, and further stimulation may cause a return to the plateau stage. This allows the possibility of multiple orgasms in both sexes. However, typically men enter this refractory period and some may find continued stimulation to be painful after the orgasmic phase. Women may not have a similar refractory period and may be able to repeat the cycle almost immediately. Many women experience clitoral hypersensitivity after orgasm, which is essentially similar to the effect of the male's refractory period. These women may be capable of additional orgasms, but the pain involved makes the prospect undesirable.
In addition, refractory periods range from human to human, with some being immediate (no refractory) and some being as long as 12 to 24 hours.
Sexual stimulation
Sexual stimulation is any stimulus that leads to, enhances and maintains sexual arousal, and may lead to ejaculation and/or orgasm...
. These phases, in order of their occurrence, are the excitement phase, plateau phase, orgasmic phase, and resolution phase. The term was coined by William H. Masters and Virginia E. Johnson
Masters and Johnson
The Masters and Johnson research team, composed of William H. Masters and Virginia E. Johnson, pioneered research into the nature of human sexual response and the diagnosis and treatment of sexual disorders and dysfunctions from 1957 until the 1990s....
in their 1966 book Human Sexual Response.
Excitement phase
The excitement phase (also known as the arousal phase or initial excitement phase) is the first stage of the human sexual response cycle. It occurs as the result of any erotic physical or mental stimulationStimulation
Stimulation is the action of various agents on nerves, muscles, or a sensory end organ, by which activity is evoked; especially, the nervous impulse produced by various agents on nerves, or a sensory end organ, by which the part connected with the nerve is thrown into a state of activity.The word...
, such as kiss
Kiss
A kiss is the act of pressing one's lips against the lips or other body parts of another person or of an object. Cultural connotations of kissing vary widely. Depending on the culture and context, a kiss can express sentiments of love, passion, affection, respect, greeting, friendship, and good...
ing, petting, or viewing erotic images, that lead to sexual arousal
Sexual arousal
Sexual arousal, or sexual excitement, is the arousal of sexual desire, during or in anticipation of sexual activity. Things that precipitate human sexual arousal are called erotic stimuli, or colloquially known as turn-ons. There are many potential stimuli, both physical or mental, which can cause...
. During the excitement stage, the body prepares for coitus, or sexual intercourse
Sexual intercourse
Sexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...
, in the plateau phase.
Excitement in both sexes
Among both sexes, the excitement phase results in an increase in heart rate, an increase in breathing rate, and a rise in blood pressureBlood pressure
Blood pressure is the pressure exerted by circulating blood upon the walls of blood vessels, and is one of the principal vital signs. When used without further specification, "blood pressure" usually refers to the arterial pressure of the systemic circulation. During each heartbeat, BP varies...
. An erection
Erection
Penile erection is a physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal...
of the nipple
Nipple
In its most general form, a nipple is a structure from which a fluid emanates. More specifically, it is the projection on the breasts or udder of a mammal by which breast milk is delivered to a mother's young. In this sense, it is often called a teat, especially when referring to non-humans, and...
s, especially upon direct stimulation, occurred in nearly all females and approximately 60% of males. Vasocongestion
Vasocongestion
Vasocongestion is the swelling of bodily tissues caused by increased vascular blood flow and a localized increase in blood pressure.Typical causes of vasocongestion in humans includes menstruation, sexual arousal, REM sleep, strong emotions, and illnesses and allergic reactions.-Illnesses:Menstrual...
of the skin, commonly referred to as the sex flush, will occur in approximately 50-75% of females and 25% of males. The sex flush tends to occur more often under warmer conditions and may not appear at all under cooler temperatures.
During the female sex flush, pinkish spots develop under the breasts, then spread to the breasts, torso, face, hands, soles of the feet, and possibly over the entire body. Vasocongestion is also responsible for the darkening of the clitoris and the walls of the vagina during sexual arousal.
During the male sex flush, the coloration of the skin develops less consistently than in the female, but typically starts with the epigastrium (upper abdomen), spreads across the chest, then continues to the neck, face, forehead, back, and sometimes, shoulders and forearms.
The sex flush typically disappears soon after orgasm occurs, but this may take up to two hours or so, and sometimes, intense sweating will occur simultaneously. The flush usually diminishes in reverse of which it appeared.
An increase in muscle tone (myotonia
Myotonia
Myotonia is a symptom of a small handful of certain neuromuscular disorders characterized by the slow relaxation of the muscles after voluntary contraction or electrical stimulation. Generally, repeated effort is needed to relax the muscles, and the condition improves after the muscles have warmed...
) of certain muscle groups, occurring voluntarily and involuntarily, begins during this phase among both sexes. Also, the external anal sphincter may contract randomly upon contact (or later during orgasm
Orgasm
Orgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...
without contact).
Sexual excitement in both sexes can be strongly modified by subjective psychological factors. Neuro-psychoanalyst Mark Blechner calls this "the Lady Chatterley phenomenon" based on the passage in the D. H. Lawrence
D. H. Lawrence
David Herbert Richards Lawrence was an English novelist, poet, playwright, essayist, literary critic and painter who published as D. H. Lawrence. His collected works represent an extended reflection upon the dehumanising effects of modernity and industrialisation...
novel Lady Chatterley's Lover
Lady Chatterley's Lover
Lady Chatterley's Lover is a novel by D. H. Lawrence, first published in 1928. The first edition was printed privately in Florence, Italy with assistance from Pino Orioli; it could not be published openly in the United Kingdom until 1960...
in which Lady Chatterley is first completely unexcited during intercourse and ridicules the sex act, and then, shortly thereafter, becomes intensely sexually excited.
Excitement in males
In males, the beginning of the excitement phase is observed when the penisPenis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
becomes partially erect, often after only a few seconds of erotic stimulation. The erection
Erection
Penile erection is a physiological phenomenon where the penis becomes enlarged and firm. Penile erection is the result of a complex interaction of psychological, neural, vascular and endocrine factors, and is usually, though not exclusively, associated with sexual arousal...
may be partially lost and regained repeatedly during an extended excitement phase. Both testicles become drawn upward toward the perineum
Perineum
In human anatomy, the perineum is a region of the body including the perineal body and surrounding structures...
, notably in circumcised
Circumcision
Male circumcision is the surgical removal of some or all of the foreskin from the penis. The word "circumcision" comes from Latin and ....
males where less skin is available to accommodate the erection. Also, the scrotum
Scrotum
In some male mammals the scrotum is a dual-chambered protuberance of skin and muscle containing the testicles and divided by a septum. It is an extension of the perineum, and is located between the penis and anus. In humans and some other mammals, the base of the scrotum becomes covered with curly...
can tense and thicken during the erection process.
Excitement in females
In females, venous patterns across the breasts become more visible and the breasts slightly increase in size, which becomes more observable if lying on the back. The labia majoraLabia majora
The labia majora are two prominent longitudinal cutaneous folds that extend downward and backward from the mons pubis to the perineum and form the lateral boundaries of the pudendal cleft, which contains the labia minora, interlabial sulci, clitoral hood, clitoral glans, frenulum clitoridis, the...
become flatter, thinner, and rise upwards and outwards in nulliparous women (those who have not given birth). In parous women (those who have given birth), they may increase two or threefold in size. The labia minora
Labia minora
The labia minora , also known as the inner labia, inner lips, or nymphae, are two flaps of skin on either side of the human vaginal opening, situated between the labia majora...
may increase in size and may protrude from the labia majora, depending on the size they are in a relaxed state. The clitoral glans
Clitoral glans
The clitoral glans is an external portion of the clitoris.- Anatomy :It is covered by the clitoral hood, which is also external and attached to the labia minora...
becomes tumescent
Tumescence
Tumescence is the quality or state of being tumescent or swollen. Tumescence usually refers to the normal engorgement with blood of the erectile tissues, marking sexual excitation and possible readiness for sexual activity...
, or swollen, like the glans
Glans penis
The glans penis is the sensitive bulbous structure at the distal end of the penis. The glans penis is anatomically homologous to the clitoral glans of the female...
of the penis and vaginal lubrication
Vaginal lubrication
Vaginal lubrication is a lubricating fluid that is naturally produced in a woman's vagina. Vaginal lubrication or moistness is present at all times, but production increases significantly during a woman's sexual arousal in anticipation of sexual intercourse...
is produced by the vasocongestion of the vaginal walls. They darken in color and become smoother than normal. Also, the uterus
Uterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
elevates, more vertically as time passes, and the inner two-thirds of the vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
expand, usually a total of 7 to 10 cm.
Plateau phase
The plateau phase is the period of sexual excitement prior to orgasmOrgasm
Orgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...
. The phase is characterised by an increased circulation and heart rate in both sexes, increased sexual pleasure with increased stimulation, and further increased muscle tension. Also, respiration continues at an elevated level.
Plateau in Males
During this phase, the male urethral sphincterUrethral sphincter
The term urethral sphincter refers to one of two muscles used to control the exit of urine in the urinary bladder through the urethra. The two muscles are the external urethral sphincter and the internal urethral sphincter...
contracts (so as to prevent urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
from mixing with semen
Semen
Semen is an organic fluid, also known as seminal fluid, that may contain spermatozoa. It is secreted by the gonads and other sexual organs of male or hermaphroditic animals and can fertilize female ova...
, and guard against retrograde ejaculation
Retrograde ejaculation
In the human male reproductive system, retrograde ejaculation occurs when semen, which would normally be ejaculated via the urethra, is redirected to the urinary bladder. Normally, the sphincter of the bladder contracts before ejaculation forcing the semen to exit via the urethra, the path of least...
) and muscles at the base of the penis
Penis
The penis is a biological feature of male animals including both vertebrates and invertebrates...
begin a steady rhythmic contraction. Males may start to secrete seminal fluid or pre-ejaculatory fluid and the testicles rise closer to the body.
Plateau in Females
At this stage females show a number of effects. The areolaAreola
This article is about the breast tissue. For the entomology term, see the glossary of Lepidopteran terms. For an artistic cloud motif, see aureola. For the cactus feature, see Areole....
and labia further increase in size, the clitoris
Clitoris
The clitoris is a sexual organ that is present only in female mammals. In humans, the visible button-like portion is located near the anterior junction of the labia minora, above the opening of the urethra and vagina. Unlike the penis, which is homologous to the clitoris, the clitoris does not...
withdraws slightly and the Bartholin glands produce further lubrication
Vaginal lubrication
Vaginal lubrication is a lubricating fluid that is naturally produced in a woman's vagina. Vaginal lubrication or moistness is present at all times, but production increases significantly during a woman's sexual arousal in anticipation of sexual intercourse...
. The tissues of the outer third of the vagina swell considerably, and the pubococcygeus muscle
Pubococcygeus muscle
The pubococcygeus muscle or PC muscle is a hammock-like muscle, found in both sexes, that stretches from the pubic bone to the coccyx forming the floor of the pelvic cavity and supporting the pelvic organs. It is part of the levator ani group of muscles.-Function:The Pubococcygeus muscle controls...
tightens, reducing the diameter of the opening of the vagina and creating what Masters and Johnson refer to as the orgasmic platform
Orgasmic platform
The orgasmic platform is the tissues of the outer third of the vagina, labeled by Masters and Johnson. They swell considerably, and the pubococcygeus muscle tightens, reducing the diameter of the opening of the vagina. During orgasm, women experience rhythmic contractions of the orgasmic platform....
. For those who never achieve orgasm, this is the peak of sexual excitement. Both men and women may also begin to vocalize involuntarily at this stage.
Prolonged time in the plateau phase without progression to the orgasmic phase may result in frustration if continued for too long (see orgasm control
Orgasm control
Orgasm control, also known as "edging", "peaking", "surfing", and by other terms, is a sexual technique which involves the maintenance of a high level of sexual arousal for an extended period of time without reaching orgasm, although orgasm can be reached eventually. If orgasm is not reached after...
).
Orgasmic phase
Orgasm is the conclusion of the plateau phase of the sexual response cycle and is experienced by both males and females. It is accompanied by quick cycles of muscle contraction in the lower pelvic muscles, which surround both the anus and the primary sexual organs. Women also experience uterineUterus
The uterus or womb is a major female hormone-responsive reproductive sex organ of most mammals including humans. One end, the cervix, opens into the vagina, while the other is connected to one or both fallopian tubes, depending on the species...
and vagina
Vagina
The vagina is a fibromuscular tubular tract leading from the uterus to the exterior of the body in female placental mammals and marsupials, or to the cloaca in female birds, monotremes, and some reptiles. Female insects and other invertebrates also have a vagina, which is the terminal part of the...
l contractions. Orgasms are often associated with other involuntary actions, including vocalizations and muscular spasms in other areas of the body, and a generally euphoric sensation. Heart rate is increased even further.
Orgasm in Males
In men, orgasm is usually associated with ejaculationEjaculation
Ejaculation is the ejecting of semen from the male reproductory tract, and is usually accompanied by orgasm. It is usually the final stage and natural objective of male sexual stimulation, and an essential component of natural conception. In rare cases ejaculation occurs because of prostatic disease...
. Each ejection is associated with a wave of sexual pleasure, especially in the penis and loins. Other sensations may be felt strongly among the lower spine, or lower back. The first and second convulsions are usually the most intense in sensation, and produce the greatest quantity of semen. Thereafter, each contraction is associated with a diminishing volume of semen and a milder wave of pleasure.
Orgasm in Females
Orgasms in females may also play a role in fertilization. The muscular spasms are theorized to aid in the locomotion of spermSperm
The term sperm is derived from the Greek word sperma and refers to the male reproductive cells. In the types of sexual reproduction known as anisogamy and oogamy, there is a marked difference in the size of the gametes with the smaller one being termed the "male" or sperm cell...
up the vaginal walls into the uterus.
Resolution phase
The resolution phase occurs after orgasm and allows the muscles to relax, blood pressure to drop and the body to slow down from its excited state.Men and women may or may not experience a refractory period, and further stimulation may cause a return to the plateau stage. This allows the possibility of multiple orgasms in both sexes. However, typically men enter this refractory period and some may find continued stimulation to be painful after the orgasmic phase. Women may not have a similar refractory period and may be able to repeat the cycle almost immediately. Many women experience clitoral hypersensitivity after orgasm, which is essentially similar to the effect of the male's refractory period. These women may be capable of additional orgasms, but the pain involved makes the prospect undesirable.
In addition, refractory periods range from human to human, with some being immediate (no refractory) and some being as long as 12 to 24 hours.
See also
- Erogenous zoneErogenous zoneAn erogenous zone is an area of the human body that has heightened sensitivity, the stimulation of which may result in the production of erotic sensations or sexual excitement.People have erogenous zones all over their bodies, but which areas are more sensitive than others vary...
- Estrous cycleEstrous cycleThe estrous cycle comprises the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. Estrous cycles start after puberty in sexually mature females and are interrupted by anestrous phases or pregnancies...
- ForeplayForeplayIn human sexual behavior, foreplay is a set of intimate psychological and physically intimate acts between two or more people meant to create desire for sexual activity and sexual arousal. Either or any of the sexual partners may initiate the foreplay, and they may not be the active partner during...
- Oral sexOral sexOral sex is sexual activity involving the stimulation of the genitalia of a sex partner by the use of the mouth, tongue, teeth or throat. Cunnilingus refers to oral sex performed on females while fellatio refer to oral sex performed on males. Anilingus refers to oral stimulation of a person's anus...
- OrgasmOrgasmOrgasm is the peak of the plateau phase of the sexual response cycle, characterized by an intense sensation of pleasure...
- Sexual attractionSexual attractionSexual attractiveness or sex appeal refers to an individual's ability to attract the sexual or erotic interest of another person, and is a factor in sexual selection or mate choice. The attraction can be to the physical or other qualities or traits of a person, or to such qualities in the context...
- Sexual intercourseSexual intercourseSexual intercourse, also known as copulation or coitus, commonly refers to the act in which a male's penis enters a female's vagina for the purposes of sexual pleasure or reproduction. The entities may be of opposite sexes, or they may be hermaphroditic, as is the case with snails...