Human Development Menstrual Cycle

• Fertilization


  The process in which gametes (an egg and sperm) fuse to form a zygote
• Fertilization


  1. Occurs in the fallopian tube

  2. Results in a unicellular zygote
• Cleavage


  1. Rapid, multiple rounds of cell division

  2. Zygote undergoes its first mitotic division to produce two identical cells

  3. Division continues through mitosis to develop as many cells as possible
• Morula


  Solid mass of blastomeres resulting from a number of cleavages of a zygote, or fertilized egg
• Cleavage


  Produces a morula, a 16-celled embryo
• Blastula


  Embryo with over 100 cells, usually a spherical layer of cells (the blastoderm) surrounding a fluid-filled or yolk-filled cavity (the blastocoel)
• Blastocyst


  A distinctive stage of a mammalian embryo, a form of blastula that develops from a berrylike cluster of cells, the morula
• Cleavage


  Produces a blastocyst, characterized by an inner cell mass distinct from the surrounding blastula
• Implantation


  The process by which the embryo attaches to the endometrial surface of the uterus and invades the epithelium and then the maternal circulation to form the placenta
• Implantation


  Attachment of blastocyst to endometrium of uterus, start of pregnancy
• Gestation


  The period in which an embryo develops inside the womb of a woman, from fertilization to childbirth
• Menstruation


  The monthly shedding of the lining of the uterus, also known as menses, menstrual period, menstrual cycle or period
• Menstrual blood


  Partly blood and partly tissue from the inside of the uterus, flows from the uterus through the cervix and out of the vagina
• Menstrual cycle


  A natural process, a rhythmical series of physiological changes that occur in fertile women under the control of the endocrine system
• Menarche


  A woman's first menstruation, typically occurs around age 12
• Menopause


  The end of a woman's reproductive phase, commonly occurs between ages 45 and 55
• Normal menstrual cycle length

  Average 28 days, can range from 21 to 35 days
• Normal period length


  3 to 7 days
• Symptoms of getting your period

  • Cramps
  • Mood changes
  • Trouble sleeping
  • Headache
  • Food cravings
  • Bloating
  • Breast tenderness
  • Acne
• Menstrual phase


  1. First stage of the menstrual cycle, when females get their period

  2. The egg from the previous cycle isn't fertilized

  3. Levels of estrogen and progesterone drop

  4. The uterus sheds its inner lining
• Follicular phase


  1. Begins on the first day of menstruation, lasts until day 13

  2. The hypothalamus sends a signal to the pituitary gland to stimulate egg cells in the ovaries to grow

  3. One egg cell begins to mature in a follicle

  4. It takes 13 days for the egg cell to reach maturity
• Ovulation phase


  Occurs on day 14
• Luteal phase


  Occurs from day 15 to 28
• Sperm and egg cell

  1. An egg is released from an ovary into a fallopian tube

  2. Sperm move from the vagina through the cervix and uterus to the fallopian tubes to reach the egg

  3. The fertilized egg (zygote) divides repeatedly as it moves down the fallopian tube to the uterus
• Blastula (morula & blastocyst)

  1. The zygote becomes a solid ball of cells (morula)

  2. Then it becomes a hollow ball of cells called a blastocyst

  3. About 6 days after fertilization, the blastocyst attaches to the uterine lining (implantation)
• Embryo


  1. Develops within the amniotic sac under the uterine lining

  2. Characterized by formation of internal organs and external body structures

  3. The brain and spinal cord (neural tube) begin to develop

  4. The heart and major blood vessels begin to develop by about day 16
• Fetus (3-9 months)


  1. Develops and grows inside the uterus

  2. The fetal period begins at 9 weeks after fertilization and ends at birth

  3. By 12 weeks, the fetus fills the entire uterus

  4. By 14 weeks, the sex can be identified

  5. By 16-20 weeks, the pregnant woman can feel the fetus moving

  6. By 24 weeks, the fetus has a chance of survival outside the uterus
• Baby to adulthood


  Continues development after birth
• Fertilization


  The process in which gametes (an egg and sperm) fuse to form a zygote
• Fertilization


  1. Occurs in the fallopian tube

  2. Results in a unicellular zygote
• Cleavage


  1. Rapid, multiple rounds of cell division

  2. Zygote undergoes first mitotic division to produce two identical cells

  3. Division continues through mitosis to develop as many cells as possible
• Morula


  Solid mass of blastomeres resulting from a number of cleavages of a zygote, or fertilized egg
• Cleavage


  Produces a morula, a 16-celled embryo
• Blastula


  Embryo with over 100 cells, usually a spherical layer of cells (the blastoderm) surrounding a fluid-filled or yolk-filled cavity (the blastocoel)
• Blastocyst


  A distinctive stage of a mammalian embryo, a form of blastula that develops from a berrylike cluster of cells, the morula
• Cleavage


  Produces a blastocyst, characterized by an inner cell mass distinct from the surrounding blastula
• Implantation


  The process by which the embryo attaches to the endometrial surface of the uterus and invades the epithelium and then the maternal circulation to form the placenta
• Implantation


  Attachment of blastocyst to endometrium of uterus, start of pregnancy
• Gestation


  The period in which an embryo develops inside the womb of a woman, from fertilization to childbirth
• Menstruation


  The monthly shedding of the lining of the uterus, also known as menses, menstrual period, or period