Ovary
Uterus
Egg cell
Cycle
The continued existence of humanity is ensured by the birth of children, so reproduction is a very important part of life. Human reproduction is sexual reproduction, where two gametes fuse together. Gametes are produced by the gonads, which are connected to accessory genital organs responsible for maturation, protection and transport of gametes. The most important difference between men and women is the structure of genital organs. Apart from this there are usually characteristic differences between physique, body hair, voice, behavior and the emotional life of the two biological genders.
The female reproductive organs are located in the pelvis. The gonad is the ovary, in which the egg cells form. Ovaries are surrounded by the fimbriae of the fallopian tubes that look like finger-like branches. The fallopian tubes lead to the uterus which is located in the lower part of the abdominal cavity. The vagina is part of the female genital tract. It has a muscular wall. Its outer opening is surrounded by the labia minora and labia majora which are the external genital organs. At the junction of the labia minora is the clitoris, which is able to erect similarly to the penis. Following menarche the female reproductive organs operate cyclically, according to a 28-day rhythm. The menstrual cycle is suspended during pregnancy and it finally ends with menopause.
The ovaries are plum-sized organs, which are attached to the sides of the uterus via ligaments. Thousands of primary follicles are located in them, from which usually one starts to mature every 28 days after menarche. The maturing follicle grows in size and on the 14th day ovulation occurs. The ovary releases the mature egg cell and it proceeds into the fallopian tube. From the corona radiata od the follicle evolves the corpus luteum . If fertilization doesn’t take place the corpus luteum atrophies by end of the cycle. During the cycle two kinds of hormones are produced in the ovaries, oestrogen and progesterone.
The uterus is a muscular-walled organ located in the lower third of the abdominal cavity. Its task is to protect and nurture the developing fetus. Its lower part is the tightly closing cervix, which has an opening towards the vagina, this is the orifice of the uterus. The structure of the endometrium changes according to a 28-day rhythm. Affected by the hormones produced in the ovaries it gets thicker at the beginning of the cycle, its blood supply increases and it gradually becomes suitable to receive the fertilized egg. If fertilization doesn’t take place then its vessels contract after the corpus luteum atrophies. On the 28th day the thickened endometrium is shedded, this is accompanied by bleeding. This is called menstruation.
The egg cell suitable for fertilization is produced by meiosis, a cell division that halves the chromosomes. Primary egg cells in the ovary are surrounded by corona radiata. These are the primary follicles, which form in the ovaries of female children in early fetal stage already.
Following menarche usually one follicle matures during a cycle. The egg cell in the follicle also changes, it becomes large and round and incapable of active movement when mature, and it will contain surplus nutrients. The egg cell is fertile for about 1 day following ovulation.
The menstrual cycle is regulated by hormones produced by the pituitary gland and the ovaries. Follicle development in the ovary is triggered by the stimulating hormones produced in the pituitary, and these hormones also affect ovulation and the development of the corpus luteum. These hormones are not produced continuously, their secretion is cyclical. Because of this the reproductive function of women is cyclical, this is the menstrual cycle. This cycle is influenced by the estrogen and progesterone produced by the ovaries, which among other functions affect the structure of the endometrium. The hormones regulating the female sexual cycle interact in a complex way.
