GCSE Science Hormones

 

    The menstrual aeon is a aeon of contest that occurs in the abyss (uterus) and ovaries of changeable mammals. It is associated with the assembly of eggs and advancing the uterus for the article of fertilised eggs .

    The menstrual aeon occurs over aperiod of about 28 days. The changes during the aeon are due to four hormones, progesterone, oestrogen, FSH (follicle aesthetic hormone) and LH (luteinising hormone). Progesterone and oestrogen accept advanced alignment furnishings on the physique but in the ambience of the menstrual aeon progesterone is mainly complex in advancement the lining of the uterus and oestrogen is mainly anxious with architecture up the lining of the uterus. FSH stimulates the assembly of eggs and LH stimulates the absolution of the egg. FSH and LH are produced by the pituitary gland in the brain.

    There are four stages in the menstrual cycle.

    Stage 1. Canicule 1-4. Menstruation (bleeding) occurs. The lining of the uterus disintegrates and is shed. This is due to low levels of progesterone.

    Stage 2. Canicule 4-14. The uterine lining grows back. This is due to top levels of oestrogen.

    Stage 3. Day 14. The egg (called an ovum) is released. This is due to LH.

    Stage 4. Canicule 14-28. The lining of the uterus is maintained in case the egg becomes fertilised and built-in in the uterus. Aliment of the lining is due to top levels of progesterone.

    The four hormones collaborate with anniversary other. FSH causes Oestrogen absolution and oestrogen inhibits FSH. LH stimulates both oestrogen and progesterone production. Afore ovulation LH absolution is angry by oestrogen but afterwards ovulation it is inhibited by both oestrogen and progesterone.

    In summary, the hormones accept the afterward effects:

    :Oestrogen: causes advance of the uterine lining. Inhibits FSH. Stimulates absolution of LH and appropriately absolution of the egg. Inhibits LH afterwards ovulation.

    :Progesterone: maintains the uterine lining. Inhibits LH afterwards ovulation.

    :LH: Stimulates the absolution of the egg (called ovulation). Stimulates oestrogen and progesterone production.

    :FSH: Stimulates egg development and the absolution of oestrogen.

    Birth ascendancy tablets accommodate top levels of progesterone and oestrogen. The oestrogen inhibits FSH assembly so that eggs cease to develop.

    FSH is acclimated to amusement infertility because it stimulates the assembly of eggs.

    The menstrual aeon is catchy to learn. The best access is apparently to breach it down into parts.

    This area deals with capacity that are alfresco the GCSE syllabus.

    At a added avant-garde akin the menstrual aeon is disconnected into phases as apparent in the diagram.