Question

What is a menstrual cycle? Describe it in brief.

Answer 1

Hint: Menstrual cycle is a developmental stage that occurs in the population of primate females. Several different glands and hormones produced by glands control the cycle.

Complete answer: The menstrual cycle is the monthly series of changes a woman's body goes through in preparation for the possibility of pregnancy. The average menstrual cycle period is 28-29 days, but this can differ between women and from one cycle to the next. From the first day of the process until the day before the next duration starts, the length of the menstrual cycle is determined. There are four major phases of the menstrual cycle.
a) Menstruation is the removal of the thickened lining of the uterus from the body via the vagina. They are; menstruation, follicular phase, ovulation, and the luteal phase. Blood, uterine lining cells and mucus are present in the menstrual fluid. The average length of the cycle is between three days and one week.
b) Follicular phase - On the first day of menstruation, the follicular process begins and ends with ovulation. The pituitary gland releases follicle-stimulating hormone (FSH) released by the hypothalamus. The ovary is triggered by the FSH hormone to produce about five to 20 bead follicles on the surface. Each follicle produces an egg that is immature. Usually, only one follicle, while the others die, matures into an egg. On the 10th day of a 28-day cycle, this will occur. In anticipation of potential birth, the production of follicles causes the lining of the uterus to thicken.
c) Ovulation - Ovulation is the removal of a mature egg from the surface of the ovary. This usually occurs in the middle of the cycle, about two weeks or so before the start of menstruation. The formation of the follicle causes a rise in the amount of oestrogen during the follicular period. These increasing levels are identified by the brain hypothalamus and a chemical called the gonadotropin-releasing hormone (GnRH) is published. The pituitary gland is activated by this hormone to produce elevated luteinizing hormone (LH) and FSH levels. Ovulation is activated by a higher LH level within two days. The egg is absorbed by waves of small hair-like projections in the fallopian tube and in the direction of the uterus. The average egg life-cycle is just 24 hours. It will die if it does not meet the sperm at this point.
d) Luteal phase - After ovulation, the egg bursts from its follicle, but the broken follicle remains on the surface of the ovary. The follicle is converted into a structure known as the corpus luteum for the next two weeks or so. Along with limited levels of oestrogen, this arrangement continues to produce progesterone. The thickened lining of the uterus is protected by this combination of hormones, preparing for the fertilised egg to stick. In the lining of the uterus, if the egg implant is fertilised, it releases the hormones needed to support the corpus luteum. This includes human chorionic gonadotropin (HCG), which is a hormone contained in the urine during pregnancy tests. The corpus luteum continues to release the requisite elevated levels of progesterone to preserve the thickened uterine lining. The corpus luteum will wither and die if there is no pregnancy, usually around day 22 of the 28-day cycle. A reduction in the amount of progesterone causes the uterine lining to split apart. It's referred to as menstruation.

Note: On average, between the ages of 11 and 14, girls have their first cycle (menarche). At this point, other sexual features, such as pubic hair and budding breasts, have grown. Regular cycles from 21 to 40 days are normal.