What are these basic facts about?
• The cycle is 28 days long
• The breakdown of uterus lining is triggered by low
levels ...
Mr. Matthews

Tuesday 5 November 2013

The Menstrual Cycle
State the hormones of the menstrual cycle
Understand the basic ...
Hormones
• Four hormones involved in controlling
menstruation
Name

Made…

Function

FSH

Pituitary

Stimulates one egg ce...
An oocyte (pre-ovum)
surrounded by follicle cells
False colour SEM of human uterus wall, approximately 13 days into cycle.
Green cells are secretory, and orange cells are c...
• Initial concentrations of oestrogen are low.
• The low concentration has a negative
feedback effect on the secretion of ...
Negative feedback lowers
FSH concentration
Positive feedback from
increasing oestrogen
concentration causes
increase in FSH and LH from
pituitary gland.

Follicle ge...
• Peak of LH causes follicle to burst and release
ovum
• This is ovulation (on day 14 of the cycle)
• Follicle reforms to ...
Peak of LH causes ovulation
(day 14)

Oestrogen falls because
follicle is gone, but corpus
luteum still produces some.

Ov...
Fall in FSH and LH due to
negative feedback with
oestrogen and progesterone

Progesterone produced by
corpus luteum. Inhib...
FSH and LH totally inhibited

Breakdown of corpus luteum
causes fall in progesterone
and oestrogen

Corpus luteum begins t...
FSH begins to rise since it’s
not inhibited by oestrogen and
progesterone

Low levels of progesterone
and oestrogen becaus...
The menstrual cycle 5th November
The menstrual cycle 5th November
The menstrual cycle 5th November
The menstrual cycle 5th November
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The menstrual cycle 5th November

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For students With thanks to the TES biologist from whom this was adapted and originally came up with this excellent presentation.

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  • FSH stimulates a potential egg cell in the ovary
    The cells around the ovum also develop. This is called a follicle.
    Follicle cells secrete oestrogen.
    Oestrogen stimulates rebuilding of uterus wall.
  • The menstrual cycle 5th November

    1. 1. What are these basic facts about? • The cycle is 28 days long • The breakdown of uterus lining is triggered by low levels of oestrogen • Loss of blood and tissue is known as menstruation/ period • The release of an egg is known as ovulation
    2. 2. Mr. Matthews Tuesday 5 November 2013 The Menstrual Cycle State the hormones of the menstrual cycle Understand the basic functions of these hormones Explain how these hormones affect the female reproductive system
    3. 3. Hormones • Four hormones involved in controlling menstruation Name Made… Function FSH Pituitary Stimulates one egg cell to develop (become follicle) Oestrogen Follicle (ovary) Stimulates rebuilding of the uterus wall LH Pituitary Stimulates follicle to burst and release the ovum Progesterone Corpus Luteum (ovary) Completes development of uterus wall, promotes glycogen storage
    4. 4. An oocyte (pre-ovum) surrounded by follicle cells
    5. 5. False colour SEM of human uterus wall, approximately 13 days into cycle. Green cells are secretory, and orange cells are ciliated
    6. 6. • Initial concentrations of oestrogen are low. • The low concentration has a negative feedback effect on the secretion of FSH.
    7. 7. Negative feedback lowers FSH concentration
    8. 8. Positive feedback from increasing oestrogen concentration causes increase in FSH and LH from pituitary gland. Follicle gets bigger – releases more oestrogen
    9. 9. • Peak of LH causes follicle to burst and release ovum • This is ovulation (on day 14 of the cycle) • Follicle reforms to become structure called corpus luteum (‘yellow body’) • LH stimulates corpus luteum to produce progesterone.
    10. 10. Peak of LH causes ovulation (day 14) Oestrogen falls because follicle is gone, but corpus luteum still produces some. Ovulation – ovum released from follicle. Follicle become corpus luteum
    11. 11. Fall in FSH and LH due to negative feedback with oestrogen and progesterone Progesterone produced by corpus luteum. Inhibits FSH and LH Corpus luteum – produces progesterone. Uterus wall fully completed.
    12. 12. FSH and LH totally inhibited Breakdown of corpus luteum causes fall in progesterone and oestrogen Corpus luteum begins to break down if no embryo has implanted a week after ovulation
    13. 13. FSH begins to rise since it’s not inhibited by oestrogen and progesterone Low levels of progesterone and oestrogen because there is no follicle or corpus luteum Uterus wall breaks down due to low levels of oestrogen and progesterone New egg cell stimulated by rising FSH levels

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