Biology

• Reproductive system


  The biological system made up of all the anatomical organs involved in sexual reproduction
• Reproduction


  The creation of new individuals which is exactly from the same kind
• Human development


  1. Formation of sex cells

  2. Fertilization

  3. Cleavage

  4. Gastrulation

  5. Embryogenesis
• Zygote


  Fertilized egg
• Blastocyst


  Multicellular ball mass with a distinct inner mass cell which eventually forms the fetus
• Menstrual cycle


  The average length is 28-29 days, calculated from the first day of period to the day before the next period starts
• Menstrual phase


  1. Uterus sheds its inner lining

  2. Blood loss of 10-80 ml is normal

  3. Abdominal cramps may occur
• Follicular phase


  1. Pituitary gland secretes hormone to stimulate egg cells

  2. One egg cell begins to mature in a follicle

  3. Follicle secretes hormone to stimulate uterus lining development
• Ovulation phase


  1. Pituitary gland secretes hormone to cause ovary to release mature egg

  2. Egg is swept into fallopian tube
• Luteal phase


  1. Egg stays in fallopian tube for 24 hours

  2. If not fertilized, egg disintegrates

  3. Hormone causing uterus lining retention gets used up, leading to next menstrual phase
• Birth control pills


  A form of contraception that uses hormones to prevent pregnancy
• Ovulation


  The release of an egg from the ovary
• Hormonal contraceptives


  Prevent pregnancy by inhibiting ovulation and changing cervical mucus
• Birth control pills are not linked with an overall increased risk of cancer, but have a higher risk of breast and cervical cancers in current and recent users
• Birth control pills may slightly raise blood pressure
• Ovulation-suppressing contraceptive methods


  • Oral contraceptives
• Barrier contraceptive methods


  • Condom
  • Diaphragm
  • Cervical cap
• Condom


  A thin latex or natural membrane sheath placed over the erect penis to prevent semen from entering the vagina
• Diaphragm


  A barrier method that fits inside the vagina and prevents sperm passing through the cervix
• Cervical cap


  Keeps sperm from entering the uterus by covering the cervix
• Chemical barrier contraceptives


  • Creams, foams, and jellies with spermicidal properties
• Surgical contraceptive methods


  • Vasectomy
  • Tubal ligation
• Vasectomy


  A simple procedure that makes a man unable to father children
• Tubal ligation


  A surgical procedure to prevent pregnancy by blocking or cutting the fallopian tubes