The female menstrual cycle as a physiological process
The female menstrual cycle is a cyclic changes that occur monthly in the Central nervous system, ovaries, genitals and Breasts of a woman. All these processes are closely interrelated and have a significant impact on the work of all other organs and body systems. The slightest disturbance of the menstrual cycle always affect the nervous and cardiovascular systems, and through them on all other bodies.
The first menstruation in girls is called menarche. Women of the southern peoples menarche occurs earlier than in the North. Menstrual cycle length is determined from the first day of the onset of menstruation to the first day of the next menstruation. The average menstrual cycle length is 28 days, but the norm is its duration from 21 to 35 days.
Normal menstrual cycle consists of two phases with a predominance of the activity of female sex hormones estrogen or progesterone. The secretion of female sex hormones is under the influence of the cerebral cortex and subcortical structures responsible for the activity of the endocrine glands, hypothalamus and pituitary.
The first phase of the menstrual cycle, estrogen
During this phase the maturation of oocytes in the ovary for 13-14 days. In the ovaries of a newborn girl, there are several hundred thousand so-called primordial follicles, which consist of an oocyte surrounded by a single layer of follicular epithelium. Under the action of hormones with the onset of menarche begins the maturation of primordial follicles. During the menstrual cycle, only one follicle reaches full maturity. Ripened egg breaks the follicle and out of the ovary, getting first in the abdominal cavity, and then into the fallopian tube. The time of the release of an egg from the ovary is called ovulation, this happens usually on day 14 (28 day cycle).
The process of follicle maturation occur under the influence of ovarian hormones estrogen (primarily estradiol) and folliclestimulating hormone (FSH) in the pituitary gland (the master gland of the endocrine glands located in the brain).
Between the hormones of the pituitary and ovary have an inverse relationship: if estrogen is secreted lot, the amount of FSH is reduced and Vice versa. The number of pituitary hormones is dependent on hormones, which secretes the hypothalamus - Department of brain responsible for endocrine activity of the human body.
Simultaneously with the maturation of cyclic changes occur in the mucous membrane of the uterus is in its glands, blood vessels and actually in the mucosa - stroma. First, the mucous membrane of the uterus sloughs and menstruation arrives, then the mucosa recovers and grows.
Changes occur in the mammary glands. Under the influence of estrogens increase in the length of the ducts of the mammary glands, mammary glands swell.
The second phase of the menstrual cycle, progesterone
The second phase of the menstrual cycle starts after the release of a ripened egg from the ovary. The amount secreted by ovarian estrogen decreases sharply, and on the site of the ruptured follicle is formed temporal gland of internal secretion - luteum begins to produce progesterone.
If the task of the first phase of the menstrual cycle was to create conditions for the maturation of the egg and prepare the uterus for the introduction into it of a fertilized egg, the objective of the second phase of the menstrual cycle is the retention of a fertilized egg in the uterus.
Therefore, under the influence of progesterone dramatically reduced motor activity of smooth muscles of the uterus (this prevents miscarriage). The secretion of progesterone stimulates luteinizing hormone (LH) by the pituitary gland. At this time, the uterus begins secretory phase of the epithelium of the glands of the mucous membrane of the uterus begins to develop a secret, which prepares the uterus to receive the embryo.
If fertilization occurs, the first 10 days, the fertilized egg moves through the fallopian tube to the entrance into the uterus. After getting into the uterus of the fertilized egg (embryo) is embedded in the prepared mucous membrane of the uterus and begins to grow deeper into it, connecting with the mother's body numerous blood vessels (the first 10 days, the embryo was not associated with the mother's body, he ate at the expense of own resources).
If fertilization does not occur, then luteum atrophies and becomes barely noticeable white ribbed - white body. Without progesterone, the mucous membrane begins to be rejected, and the muscles of the uterus to contract, releasing the contents of a new menstrual cycle.
Every woman should know about your menstrual cycle, its duration and other features to in case of violation of the menstrual cycle in time to see a doctor.
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