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REPRODUCTION, Male Reproductive System, Female Reproductive System -…

- - - - egg travels towards the uterus
        
        egg is not fertilised after 8-24 hours
        
        it dies
        
        sperm must reach an egg while it is quiete near the top of the oviduct if the fertilisation is to be successful
        
        semen is deposited at the top of the vagina
        
        sperm swim up through the cervix, through the uterus, and into the oviduct
        
        many will never get there at all
        
        about a 1m sperm are deposited in the vagina at once
        
        good chance that some of them will reach the egg
        
        1 more item...
  - - - single cell
        
        when it is fully developed, it bursts out of the ovary and into the funnel at the end of the oviduct
        
        OVULATION
      - adaptive features
        
        link to www.google.com
        
        Cytoplasm
        
        To provide energy for cell division in the developing zygote after fertilization
        
        Jelly coating
        
        To make an impenetrable barrier after fertilization to prevent more sperm entering the egg
    - - formed in the testis
      - stored in the epididymis
      - fluid containing sperm is called semen
        
        contains sugars and other nutrients to provide the sperm with energy
      - adaptive features
        
        link to www.google.com
        
        Flagellum
        
        Allows the sperm to swim towards the egg
        
        Acrosome
        
        To digest a route into the egg for fertilization
        
        Mitochondria
        
        To provide energy for movement of the flagellum
    - - structure
        
        male: has a head, midpiece and a tail
        
        female: round shape, contains cytoplasm, nucleus and protective layers
      - numbers
        
        millions produced continuously by testes
        
        1 released every one cycle from ovaries
      - size
        
        male: very small (much smaller than egg cells)
        
        female: large (one of the largest human cells)
      - motility
        
        male: motile, can swim using their tail
        
        female: non-motile, cannot move by themselves
  - - - embryo and placenta grow
        
        in the placenta the substances are exchanged between the mother's and embryo's blood
        
        it is the embryo's life support system
        
        after 11 weeks
        
        embryo has developed most of its organs
        
        placenta is joined to the fetus by the umbilical cord
        
        O2 and dissolved nutrients in the mother's blood diffuse across the placenta into the fetus's blood and are then carried along the cord to the fetus
        
        it is now a FETUS
        
        is surrounded by a strong membrane
        
        2 more items...
  - - - adolescence
        
        functions of the reproductive organs are strongly affected by hormones
        
        men: testosterone (ppal.)
        
        women: oestrogen and progesterone
        
        Menstrual cycle
        
        eggs develop in small structures: follicles; in the ovaries
        
        1 egg is released from a follicle into the oviduct every month
        
        2 more items...
        
        after a girl reaches puberty
        
        recurring events are controlled by 4 hormones
        
        oestrogen, progesterone, FSH and LH
        
        2 more items...
- - - - link to www.google.com
        
        petals
        
        coloured structures that attract insects or birds to a flower
        
        stamens
        
        the male parts of a flower
        
        filament
        
        the "stalk" plant of a flower
        
        anther
        
        the structure at the top of the stamen, inside where pollen grains are made
        
        sepals
        
        leaf-like structures that form a ring outside the petals of a flower
        
        carpel
        
        the female part of a flower
        
        ovary
        
        the part of the flower that holds the ovules
        
        ovules
        
        small structures that contain the female gametes
        
        style
        
        the part of a carpel that connects the stigma to the ovary
        
        stigma
        
        the part of a flower that receives pollen
    - - Transfer of pollen from the anther to the stigma.
      - Often done by insects like bees, attracted by color and scent.
        
        Bees brush past anthers, collecting pollen, and then transfer it to another flower’s sticky stigma.
        
        If the flower is of the same species, pollination has occurred.
    - - Begins after pollination.
      - A pollen grain sticks to a compatible stigma and grows a pollen tube down through the style to the ovary.
        
        The male nucleus travels down the pollen tube and enters the ovule via a hole called the micropyle.
        
        The male and female gametes fuse inside the ovule.
        
        This fusion forms a zygote — fertilisation is complete.
    - - Each fertilised ovule becomes a seed.
        
        The zygote divides by mitosis to form an embryo plant.
        
        The rest of the flower parts (petals, sepals, stamens) usually wither and fall off.