Physical characteristics of youths’ development (Part 2) The Menstrual Cycle.
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Transcript of Physical characteristics of youths’ development (Part 2) The Menstrual Cycle.
HHDPhysical characteristics of youths’ development
(Part 2)
The Menstrual Cycle
Signifies a woman’s ability to bear children
Menarche usually occurs between 11-14 years of age
On average, a menstrual cycle lasts 28 days
Involves a delicate interplay of hormones
Oestrogen, Progesterone, FSH and LH are all present during the menstrual cycle. However, the release of and contribution of these hormones occurs at different stages during the 28 day cycle.
The menstrual cycle explained
The Menstrual Cycle
Day 1-7- Bleeding commences- Lining of uterus (endometrium) is discharged- Pituitary gland releases FSH which travels in bloodstream to
the ovaries- FSH stimulates an ovum to start maturing in follicle- Follicles are small sacs that contain an immature ovum as it
developsFallopian Tube
Day 7-12- As follicles begin to mature, oestrogen is released by the
ovaries- Oestrogen travels to the uterus where it stimulates the
growth of a new blood lining to prepare for possible pregnancy
(blood lining)
Oestrogen
Day 13-15- High Oestrogen levels cause the pituitary gland
to switch from making FSH to LH, which stimulates ovulation
Oestrogen
LH
Day 14. Ovulation- The LH hormone causes the follicle to burst,
releasing an egg from an ovary into the fallopian tube.
- This process is called ovulation - Peak fertility time - The empty follicle is now called the corpus
luteum
Day 15-28- Ovum travels down fallopian tube and into uterus- Follicle keeps on making Oestrogen and Progesterone which
causes the endometrium to continue to thicken in case conception occurs
- If ovum is fertilised by sperm it implants into endometrium- Unfertilised egg dies- At end of cycle, hormone levels drop and next menstrual
cycle beings on day 28
Endometrium continues to thicken
Ovum
Follicle
Progesterone
Oestrogen