16 Reproductive System by gegeshandong

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									The Reproductive System
1.   The Male Reproductive System
2.   The Female Reproductive System
3.   The Menstrual Cycle
4.   Embryonic Development
   The Male Reproductive
          System


                                                            Urinary bladder

                                                            Pubic bone

                                                            Vas deferens

                                                            Urethra


                                                            Penis
                          Seminal
Large intestine             vesicle

              Rectum Prostate   gland
                       Bulbourethral gland                  Scrotum
                                      Epididymis
                                                   Testis
Spermatogenesis

            begins when males
            reach puberty and lasts
            into old age
            sperm are produced in
            the testes and mature in
            the epididymis
            four haploid sperm cells
            are produced from one
            diploid
            spermatogonium
            The Female Reproductive
                   System
                                         Fallopian
                                              tube
Fallopian tube
         Ovary




Urinary bladder                                      Ovary
                             Uterus
        Pubic bone

        Urethra
                              Cervix


                  Vagina   Rectum
                                       Vagina
Oogenesis - the formation of egg cells
 • females are born with up to 400,000 follicles,
   each of which contains a primary oocyte that is
   "paused" in prophase I of meiosis
 • beginning at puberty, hormones cause one
   oocyte to mature approximately every 28 days
 • each primary oocyte can produce 1 ovum (egg
   cell) and 3 polar bodies
 • meiosis II is not completed unless the egg is
   penetrated by a sperm cell
The Ovarian Cycle


         1. follicular phase - follicle
         stimulating hormone (FSH) causes a
         follicle and its oocyte to start to
         mature
         2. ovulation - luteinizing hormone
         (LH) peaks causing the follicle to
         break open and release its egg,
         causing estrogen levels to rise,
         reducing the amount of FSH and LH
         3. luteal phase - remaining follicle
         forms the corpus leuteum which
         secretes estrogen and progesterone
         which stimulate the endometrium to
         thicken in case of pregnancy.
The Menstrual Cycle

          1. menstrual phase - low levels of
          estrogen cause the endometrium
          (uterine lining) to break down and
          menstruation occurs
          2. proliferation phase - rising
          estrogen levels cause the
          endometrium to thicken
          ovulation
          3. luteal phase - further thickening
          of the endometrium, preparing for
          implantation of egg
      Fertilization and Implantation




sperm cell penetrates the egg, meiosis II is completed and a diploid
zygote is formed
by the time implantation occurs, the zygote has already divided into about
100 cells to form the blastocyst
when the first body structures appear at about nine weeks, it is called an
embryo
The Placenta                                Thought Question:
                                            How can this process result in twins?
         Amniotic sac

                   Placenta

                   Umbilical cord
                                                      Fetal      Maternal
                                                    portion of   portion of
                                                    placenta     placenta


                        Villus in chorion

                                 Amnion
Uterus
Amnion                        Umbilical cord




                                                                              Maternal
                                                                              artery

               Umbilical arteries                                             Maternal
                                                                              vein
                  Umbilical vein
         Fetal Development




Thought Question
What evidence for evolution is shown in these images?
    Ultrasound




Thought Question
How does an ultrasound work?

								
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