Ovarian and menstrual cycle Flashcards
What is the ovarian cycle and what does it involve
Series of events that take place in the ovary- maturation of secondary oocyte, release of secondary oocyte and formation of corpus luteum
What does FSH stand for and what does it cause
Stands for follicle stimulating hormone which causes one primary follicle to start to mature becoming a secondary follicle which completes meiosis 1 but stops in metaphase II
What does the secondary follicle secrete/do
Secretes oestrogen which thickens the endometrium and inhibits FSH, fills with fluid and moves to the edges of the ovary making it now the Graafian follicle
What happens during ovulation
Luteinizing hormone causes the Graafian follicle to burst and release the secondary oocyte from the ovary
What happens after ovulation
Secondary oocyte is picked up by the fimbriae and taken through the fallopian tube to the uterus, Remnants of the ruptured follicle in the ovary form the corpus luteum which secretes progesterone which maintains the lining of the uterus
How long does it take for the corpus luteum to degenerate
Around 8 days which then forms the corpus albicans which then also degenerates and another ovarian cycle begins if pregnancy doesn’t occur
Menstrual cycle
Describes the changes that occur in the lining of the uterus (endometrium), Under the control of hormones linked to the ovarian cycle, Purpose- prepare the endometrium to receive a fertilized ovum
What does the hypothalamus secrete
Gonadotropin releasing factors into the anterior pituitary which stimulates the release of FSH and LH from the anterior pituitary
What does FSH cause
causes a follicle to mature and develop in the ovary and causes the developing follicle to secrete oestrogen causing the growth and thickening of the endometrium
What happens if oestrogen levels become too high
Can inhibit FSH production by the anterior pituitary meanwhile the production of LH increases which together cause ovulation
What does LH stand for and cause
Luteinizing hormone, causes the corpus leuteum to secrete progesterone and oestrogen
What does the corpus luteum secrete
increasing amounts of progesterone and oestrogen which helps to maintain the endometrium of the uterus
What happens to the corpus luteum if pregnancy occurs
continues to develop until around the 3rd month of pregnancy when it degenerates
What happens to the corpus luteum if fertilisation doesn’t occur
corpus luteum degenerates after around 8-12 days in to the corpus albicans which then causes the oestrogen and progesterone levels to drop
Where is FSH produced and what are its functions
Anterior pituitary, stimulates follicular growth in ovaries, stimulates estrogen secretion from developing follicles
