The sexual cycle is also called the menstrual cycle. These are changes occurring periodically in the body of a woman of reproductive age, which are aimed at the probable possibility of conception. In medicine, the first day of menstruation is considered to be the beginning of the menstrual cycle. In total, it includes three phases, which we will discuss in this article. These are proliferative, menstrual and secretory. If in animals females are capable of sexual behavior at any time, then in humans, after about five hundred cycles, menopause occurs. This occurs between the ages of 46 and 54. In this condition, the ovaries become insensitive to luteotropin and follitropin.
Duration
The duration of the sexual cycle in women can be different. The physiological processes taking place in her body are of decisive importance. At the same time, there are approximate deadlines in which it should fit. If this does not happen, then there is reason to suspect various violations.
The duration of a woman's sexual cycle is 28 days. Depending on variousfactors, it can vary, becoming a week longer or shorter.
First period
To understand the concept of the estrous cycle, one should delve into the specialized terminology related to this condition. This article will discuss the basic terms.
The central event in the process of sexual development of every woman is the menarche. This is the first sexual cycle in her life. It indicates that the body is now ready for reproduction. As a rule, in women, menarche occurs at the age of twelve to fourteen years. The norm is considered to be between the ages of nine and fifteen.
When menstruation appears at the age of nine, they speak of early menarche, and at 15 years of age - of primary amenorrhea. The time at which the first menstrual bleeding occurs depends on many factors. This is nutrition, heredity, the general he alth of the girl.
Possible violations
Violations of the sexual cycle can be caused by a large number of different factors. These are pregnancy, hormonal disruptions in adolescence, and other natural causes. The menstrual cycle can also go astray due to internal and external stresses.
It is customary to talk about a delay in menstruation if there are no cyclic bleeding within 35 days. It should be noted that small delays in menstruation are considered normal. However, only if their duration does not exceed ten days.
One of the most common causes of missed periods is pregnancy. ATIn this case, a test should be purchased to confirm. If the result is negative, you should consult a gynecologist. He will understand the causes and, if necessary, prescribe the appropriate treatment.
There can be many reasons for dysregulation of the sexual cycle:
- neurological and mental illness;
- psychic upheaval;
- obesity;
- avitaminosis;
- infectious diseases;
- liver problems;
- diseases of the hematopoietic system, blood vessels or heart;
- consequences of gynecological operations;
- violation of puberty;
- genitourinary tract injury;
- genetic diseases;
- hormonal changes that occur during menopause.
It is worth noting that in adolescents, a delay in menstruation is a common occurrence. In the first couple of years after the onset of menstruation, girls rarely experience a constant cycle. In this case, do not worry, this is a common occurrence. It is due to the fact that at this age the hormonal background is still unstable, so ups and downs in mood are likely, which leads to a significant increase or decrease in the level of hormones in the blood. When hormones stop raging, the cycle immediately stabilizes. If it does not become regular two years after the start of menstruation, you should consult a gynecologist for help.
Climax
The cessation of regular periods of the sexual cycle occurs during menopause. This is characterized by the extinction of the reproductive function. irregular periods ortheir complete cessation is called menopause.
When this time comes, mainly depends on heredity. Medical interventions, in particular, gynecological operations, and certain diseases, can also have an impact. All these problems can lead to early menopause.
Phases
The processes that occur during menstruation constitute the phases of the sexual cycle, they are also called stages.
They correspond to the changes that occur in the ovaries and endometrium, that is, the inner lining of the uterus lining its cavity.
Follicular phase
The first stage of the sexual cycle is called the menstrual or follicular. At this stage, the woman begins to bleed from the uterus. This happens due to the rejection of the endometrial layer, which is abundantly supplied with blood vessels.
Rejection begins at the end of the ovarian cycle. It occurs necessarily only if the egg has not been fertilized. The beginning of the first stage of the sexual cycle or the follicular phase of the ovary is considered the very first day of menstruation. The duration of this period may be different, for each woman it is individual. During this time, the dominant follicle should finally mature. On average, it is two weeks, but the time period from seven to 22 days is considered the norm.
The course of the menstrual cycle
The follicular phase and the accompanying ovarian cyclebegin with the release of gonadoliberin by the hypothalamus. It actively stimulates the pituitary gland to secrete small amounts of luteinizing and follicle-stimulating hormones. These are, respectively, lutropin and follitropin.
Due to the reduced level of estradiol secretion, the release of lutropin and follitropin is suppressed. As a result, their level of education remains low.
Under the influence of follitropin, several follicles begin to develop in the ovaries at once. Of these, a dominant follicle stands out, which has the maximum number of receptors for folliculotropin. In addition, it most intensively synthesizes estradiol. The rest at the same time undergo atresia, that is, the reverse development of follicles in the ovary.
Over time, the level of estradiol in the body begins to rise. At its low concentration, the secretion of gonadotropins is suppressed, and at a high one, on the contrary, it is stimulated. As a result, these processes lead to a significant release of GnRH by the hypothalamus.
This effect is especially pronounced for lutropin, since a high concentration of estradiol increases the sensitivity of adenohypophysis cells. In addition, the follicles react much more intensively to lutropin due to the presence of a larger number of receptors for this hormone.
The result of this is regulation on the principle of positive feedback. The follicle continues to increase in size exactly until a sharp release of lutropin begins. This means the end of the follicular phase.
Ovulatory phase
The new phase is called ovulatory or proliferative. Around the end of the first week of the cycle, the dominant follicle is released. It continues to grow steadily, and also increases the amount of estradiol. At this time, the remaining follicles undergo reverse development.
The follicle that finally matures and is ready for ovulation is scientifically called the Graafian vesicle. It is worth noting that the ovulatory phase lasts only about three days. During this time, the main release of luteinizing hormone occurs.
Hormone release
Within one and a half to two days, several waves of release of this hormone occur in a row at once, its concentration in the plasma at this time increases significantly. The release of luteinizing hormone is the final stage of follicle development. In addition, it stimulates the production of proteolytic enzymes and prostaglandins, which are required to break the wall of the follicle and release the egg. This is directly the process of ovulation.
In parallel, the level of estradiol in the body begins to fall. A feature of the sexual cycle is that in some cases it may be accompanied by ovulatory syndrome. It is characterized by painful and uncomfortable sensations in the abdomen, iliac regions.
As a rule, ovulation occurs within a day after the maximum wave of luteinizing hormone release. A period of 16 hours to two days is considered the norm. This is an important part of the sexual reproduction cycle.
During ovulation, a woman's body releases 5 to 10 ml of follicular fluid,which contains the egg necessary for conception.
Secretory phase
This phase of menstruation is also called luteal. This is the period of time between ovulation and the onset of the next menstrual bleeding. It is also known as the corpus luteum phase. Unlike the previous follicular phase, the duration of this stage is considered to be more constant. It is from 13 to 14 days, normally it can be more or less by two days.
When a graafian vesicle ruptures, its walls immediately fall off, and luteal pigment and lipids penetrate into the cells. Due to this, it acquires a characteristic yellow color. After transformation, the follicle is already called the corpus luteum.
In total, the duration of the luteal phase depends on the period of functioning of the corpus luteum. As a rule, it is ten to twelve days. At this time, it secretes estradiol, progesterone and androgens. In the presence of elevated levels of progesterone and estrogen, the outer layers of the endometrium change. Her glands mature, begin to secrete and proliferate. This is a clear sign that the uterus is preparing to receive a fertilized egg.
Estrogen and progesterone reach their peak around the middle of the luteal phase, in parallel, the amount of the corresponding hormones decreases.
If pregnancy does not occur…
When the egg remains unfertilized, the corpus luteum stops functioning after a while. The level of progesterone and estrogen decreases. This results in swelling andnecrotic changes in the endometrium.
Due to the decrease in the level of progesterone, the synthesis of prostaglandins also increases. When the egg is not fertilized, after some time luteolysis begins in the corpus luteum, that is, structural destruction, since it is no longer able to synthesize estradiol and progesterone.
Because of this process, the secretion of lutropin and follitropin is no longer suppressed. The secretion of these hormones increases, which leads to the stimulation of a new follicle. With a decrease in the level of progesterone and estrogen, the synthesis of follicle-stimulating and luteinizing hormones resumes. Thus begins a new cycle in the woman's body.
Stages of arousal
An important place in the reproductive system is occupied by the stages of excitation of the sexual cycle. There are three of them in total. These are excitation, inhibition and balancing. During this period, changes occur, some of which are easy to notice, while others are elusive even for modern biological devices.
At the stage of sexual arousal in the female body, follicles mature and ovulation occurs. During this period, he is ready to conceive.
During inhibition, signs of sexual arousal appear much weaker. Then comes the stage of balancing, which continues again until a new stage of excitation. During this period, the woman is in the most balanced state. This is influenced by the processes that occur in the body.
