Menstruation (Start with what we know and love :/) Flashcards
4 main hormones?
Follicle stimulating hormone (FSH)
Luteinising hormone (LH)
Oestrogen
Progesterone
Where does FSH come from?
Anterior pituitary
Where does LH come from?
Anterior pituitary
Where does oestrogen come from?
Follicles in ovaries and corpus luteum
Where does progesterone come from?
Corpus luteum
Other hormones presnet?
Gonadotrophin releasing hormone (GRH)
Human chorionic gonadotrophin (hCG)
Where does GRH come from?
Hypothalamus
Where does Human Chorionic gonadotrophin come from?
Embryo
2 phases of menstruation?
Follicular phase (ovum in follicle) Luteal phase
When is follicular phase?
Approx first 14 days but variable
When is luteal phase?
14 days before period
What surround oocytes and what does it form?
Granulosa cells
To form
Follicles
What stages of development do follicles go through in the ovary?
- Primordial follicles
- Primary follicles
- Secondary follicles
- Antral follicles
What happens in follicular phase?
-One follicle develops further than others and becomes dominant follicle
LH spikes just before ovulation, causing dom follicle yo release ovum from ovary
What do granulosa cells surrounding follicles secrete?
Oestrogen, having -ve FB effect on pituitary gland, reducing quantity of LH and FSH produced
What happens after ovulation?
-Follicle which releases ovum collapses and becomes corpus luteum
What does corpus luteum do?
Secretes high levels of progesterone, maintaining endometrial lining
What does progesterone cause?
-Cervical mucus to become thick and no longer penetrable
Fall in what causes corpus luteum to degenerate?
No production of hCG and it stops producing oestrogen and progesterone = menstruation
What do stromal cells of endometrium do?
Release PGs (prostaglandins) which encourage the endometrium to break down and uterus to contract
When does menstruation start?
Day 1 of cycle
What secretes hCG specifcally?
The syncytiotrophoblast of the embryo
