Luteal phase

Luteal phase

After ovulation, the remains of the ovarian follicle form the corpus luteum. This yellow glandular tissue secretes large amounts of progesterone and smaller amounts of oestrogens. These hormones stimulate further development of the mammary glands and the luteus in anticipation of pregnancy
If the oocyte is not fertilised within about 36 hours of being shed into the oviduct, it dies. Following this the corpus luteum gets smaller with the result that progesterone and oestrogn secretion is reduced. At day 28, about 14 days after ovulation, lack of progesterone bings about another menstruation and the cycle begins again
If the oocyte is fertilised, the zygote is propelled towards the luteus. during its journey it forms an embryo which becomes implanted in the uterine lining. A placenta forms between the embryo and mother; this produces human chloride gonadotrophin (HCG) which stpos the degeneration of the corpus luteum, and menstruation is suspended.In humans menstruation occurs in females from puberty to menopause, after which there are no more fertile follicles so follicular and ovulation cease.

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	Created by harry_bygraves almost 11 years ago