The Menstrual Cycle Flashcards
What is the menstrual cycle?
The menstrual cycle is a series of events that occurs every 28 days on average in the female if fertilisation has not taken place
When does the menstrual cycle begin?
It begins at puberty
When does the menstrual cycle end?
It continues until the menopause
What is the menopause?
The menopause is when ovulation and menstruation stop happening in a female
Between what ages does the menopause usually occur?
Usually between the ages of 45 and 55
The events of a typical menstrual cycle can be summarised under what headings?
(4)
Days 1-5
Days 6-14
Day 14
Day 14-28
What occurs between days 1-5 of the menstrual cycle?
4
The old lining of the uterus/the endometrium breaks down and is shed from the body
The loss of blood and tissue through the vagina is called the menstruation
Meiosis occurs in an ovary to produce a new egg
The new egg is surrounded by the Graafian follicle
Between days 1-5, what breaks down and is shed from the body?
The old lining of the uterus is shed
What is called menstruation?
The loss of blood and tissue (the old lining of the uterus) through the vagina
What is produced between days 1 and five?
A new egg is produced
What happens to the newly produced egg between days 1 and 5?
It is surrounded by the Graafian follicle
What occurs between days 6-14 of the menstrual cycle?
2
The developing Graafian follicle produces oestrogen which causes the endometrium to thicken again
Oestrogen prevents new eggs from developing so normally only one Graafian follicle develops during each menstrual cycle
What produces oestrogen between days 6-14?
The developing Graafian follicle produces oestrogen
What causes the endometrium to thicken between days 6-14?
Oestrogen produced by the developing Graafian follicle
What does oestrogen prevent from happening between days 6-14?
Oestrogen prevents new eggs from developing
What prevents new eggs from developing between days 6-14?
Oestrogen
What occurs at day 14?
4
Ovulation occurs when the Graafian follicle burst to release the egg from the ovary
The egg passes into the abdomen of the female and on into the funnel of the Fallopian tube
The egg is then moved along the Fallopian tube
The egg is normally only available for fertilisation for up to 48 hours after ovulation
For how long is the egg available for fertilisation after ovulation?
48 hours
When does ovulation occur on day 14?
It occurs when the Graafian follicle burst to release the egg from the ovary
What happens after ovulation on day 14?
The egg passes into the abdomen of the female and on into the funnel of the Fallopian tube
What happens to the egg after it has passed into the funnel of the Fallopian tube on day 14?
It is moved along the Fallopian tube
What occurs between days 14 and 28 of the menstrual cycle?
9
The remains of the Graafian follicle develop into the corpus luteum (yellow body)
The corpus luteum makes the hormone progesterone (and some oestrogen) which causes the endometrium to thicken even more
Progesterone prevents new eggs from forming
The egg that was released will die by day 16 if it is not fertilised
If fertilisation has not taken place the corpus luteum starts to degenerate around day 22
This results in a reduction in progesterone levels, which causes the lining of the uterus to break down on day 28
On day 28 the spongy, nutritive lining of the uterus breaks down and is released from the body through the vagina
This bleeding is called menstruation
The onset of bleeding marks the start of a new monthly menstrual cycle
What develops into the corpus luteum between days 14 and 28?
The remains of the Graafian follicle develops into the corpus luteum (yellow body)
What is produced by the corpus luteum between days 14 and 28?
The corpus luteum makes the hormone progesterone
What does progesterone produced by the corpus luteum do between days 14 and 28?
(2)
It causes the endometrium to thicken even more
It prevents new eggs from forming
Before what day will the egg die if it is not fertilised?
It will die before day 16 if not fertilised
When will the corpus luteum start to degenerate if fertilisation does not take place?
It will begin to degenerate around day 22 if fertilisation does not take place
What does the degeneration of the corpus luteum around day 22 result in?
This results in a reduction in progesterone levels which cases the lining of the uterus to break down on day 28
What occurs on day 28?
The spongy, nutritive lining of the uterus breaks down and is released from the body through the vagina (menstruation)
What does the onset of bleeding mark?
The onset of bleeding marks the start of a new monthly menstrual cycle
Define menstruation
Menstruation is the discharge of the lining of the uterus (endometrium) and the unfertilised egg
