Question

Explain the ovarian and uterine events that occur during menstrual cycles in a human female, under the influence of pituitary and ovarian hormones respectively.

Answer 1

The daily discharge from the inner lining of the uterus via the vagina of blood and mucosal tissue (known as menses) is menstruation, also known as a period or monthly period. The first period typically starts between the ages of twelve and fifteen, a time period known as menarche.

Complete answer:

In all primates, the menstrual cycle is the reproductive cycle and starts at puberty. Menstruation occurs once every 28 days in human females.
The menstrual cycle is called the cycle of events starting from one menstruation until the next one. One ovum is released during the middle of the menstrual cycle in a process called ovulation.
The period begins with menstrual flow (3 to 5 days) caused by uterine endometrial breakdown. Liquid-state blood vessels are discharged, but this only happens when the ovum is not fertilized. The follicular phase where the primary follicles mature into Graafian follicles is followed. This stimulates endometrium regeneration.
Ovarian and pituitary hormones bring about these changes. The release of gonadotropins (LH and FSH) increases in this process.
This causes follicular growth and oestrogen is produced by the growing follicles. In the middle of the cycle (14th day), the LH and FSH are at their peak and induce ovum release by the rupture of the Graffian follicles.
The ovulatory process is called this stage. The remains of Graffian's follicles are transformed into the corpus luteum, which secretes endometrial maintenance progesterone.
The corpus luteum degenerates in the absence of fertilisation, causing endometrium disintegration and the start of a new cycle.

Note: A lack of cycles, referred to as amenorrhea, occurs when cycles do not occur before the age of 15 or have not occurred in 90 days. Other menstrual cycle complications include painful periods and irregular bleeding, such as bleeding during periods or excessive bleeding. Primates (apes and monkeys) occur in menstruation in other species.