5.2 The Menstrual Cycle Flashcards
define the menstrual cycle and what are the phases?
The monthly cyclical changes in secretion of female hormones with corresponding changes in ovaries, uterus and other sexual organs
Phases: Menstrual (before ovulation), proliferative(before) and secretary (after)
Define the ovarian cycle and what are the phases?
Production of ovarian hormones with the release of a mature ovum
Phases: follicular (before ovulation) and luteal (after ovulation)
Define endometrial cycle
Preparation for implantation: menses
When do oestrogen and progesterone have their greatest effect on the endometrium
oestrogen: 1st half
progesterone: second half
What is the role of oestrogen and the endometrium?
Causes proliferation of endometrial stroms and endometrial glands which later provide sustenance for the fertiized ovum
What are the two roles of progesterone and the endometrium?
- promotes secretory changes in endometrium: prepares the uterus for implantation, nourishes the fertilzed ovum
- Inhibits FSH production which will prevent other follicles from developing
What effects does oestrogen have on external female genitalia?
maturation at puberty and development of pubic hair
What effects does oestrogen have on fallopian tubes?
increases number and motility of cilia
What effects does oestrogen have on breasts?
growth of ducts and stroma, fat deposition
What effects does oestrogen have on skeleton
inhibits bone breakdown, stimulates bone growth, epiphyseal fusion
What effects does oestrogen have on skin
softer and more vascular
What effects does progesterone have on the uterus?
decreases frequency/intensity of uterine contractions
What effects does progesterone have on the fallopian tubes
promotes secretions necessary for nutrition and movement of fertilized ovum within the tube
What effects does progesterone have on the breasts?
promotes development of lobules and alveoli causing swelling
define menstruation
physiologic breakdown of late secretory endometrium due to spasm of spiral arterioles caused by dropping progesterone
What are the risks of the combined pill?
Thrombosis, HTN, vascular events (stroke, MI)
Benefits of combined pill
regular, less heavy periods, prevention of ovarian and endometrial cancer
How does the progesterone only pill work?
Suppresses the LH surge and ovulation and creates a viscous and scant cervical mucous to deter sperm penetration
what is an anovulatory cycle?
failure of ovum to be released
What is the menstrual bleeding during an anovulatory cycle caused by?
inability of oestrogen to maintain endometrium growth
