ANATOMY AND PHYSIOLOGY

THE MENSTRUAL CYCLE

Define the term eumenorrhea

the start of bleeding in the menstrual cycle, usually lasts 3-4 days

What are the stages of the female menstrual cycle in order

menstrual, follicular, ovulation, proliferation and secretory phase.

Explain the menstrual phase of the menstrual cycle

The menstrual phase refers to the beginning of the menstrual cycle. This is where the functional layer of the uterus lining sheds and bleeding occurs. In this phase the spiral artery of the endometrium go into spasms. There is necrosis of the endometrium and the breakdown of its tissue, leading to menstrual flow. Some women may experience dysmenorrhea which is pain or discomfort during menstruation.

What happens to the levels of estrogen and progesterone during the menstrual phase of the cycle.

oestrogen and progesterone levels re low during the menstrual phase due to the disintegration of the corpus luteum and the shedding of the uterine lining.

Explain the follicular phase of the menstrual cycle

The follicular phase beings after the bleeding/shedding of uterus lining. The pituitary gland releases follicle stimulating hormone (FSH) which stimulates the follicles in the ovaries to mature. This causes the egg to grow thus stimulating oestrogen release which promotes thickening of uterine lining in preparation for implatation

Describe the ovulation phase of the menstrual cycle

There is a surge of leutenising hormone (LH) which causes the release of an egg. This happens at around day 14. This causes the corpus luteum to from and release progesterone which supports uterine lining in preparation for pregnancy.

Describe the secretory phase of the menstrual cycle

During this phase, if no fertilisation occurs the corpus luteum breaks down, oestrogen and progesterone levels drop leading to a menstruation.