human reproduction

    Cards (22)

    • Puberty is the period during which adolescents start to develop secondary sexual characteristics
    • In men, testosterone is the main reproductive hormone produced in the testes, stimulating sperm production
    • In women, estrogen is the main reproductive hormone produced by the ovaries
    • The menstrual cycle consists of four stages
    • Stage 1: Menstruation - period of bleeding due to the breakdown of the uterus lining
    • Stage 2: Uterus lining builds up again to prepare for a fertilized egg
    • Stage 3: Ovulation - egg is released from the ovary
    • Stage 4: Maintaining the uterus lining until the end of the cycle
    • The average length of a menstrual cycle is around 28 days
    • Menstruation lasts about four days
    • Uterus lining builds up for around ten days up to day 14
    • Ovulation takes place in a single day
    • Stage 4 stretches from day 14 to day 28
    • Hormones involved in the menstrual cycle
    • Estrogen: produced in the ovaries, stimulates the uterus lining to grow
    • Progesterone: also produced in the ovaries, maintains the uterus lining
    • Luteinizing hormone (LH) and Follicle Stimulating Hormone (FSH): produced in the pituitary gland
    • Interactions of hormones in the menstrual cycle
    • Estrogen inhibits FSH
    • FSH stimulates ovaries to produce estrogen
    • High estrogen levels stimulate the release of LH, causing ovulation
    • Progesterone inhibits both LH and FSH
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