Biology chapter 16

• Contraceptive methods are used to prevent ovulation, fertilization or implantation.
• Combination pills exerts a negative feedback on the pituitary gland.
• Combination pills inhibit the secretion of LH and FSH along the cycle.
• If LH peak is prevented then ovulation doesn't occur.
• The condom prevents semen from entering the vagina.
• Diagphragm covers the external part of the cervix and prevents the passage of sperm.
• Female sterilization (tubal ligation) prevents meeting of the oocyte with the sperm cells in the fallopian tube.
• Male sterilization (vasectomy) is a surgical procedure that prevents the passage of sperm from the testis to the penis.
• Contraceptive pills are

  1. Combination pills
  2. mini-pills
  3. morning after pills
• combination pills acts at 2 levels, at the level of the hypothalamo-pituitary axis and at the level of the uterus and the cervix.
• The cervical mucus is dense and abundant when using contraceptive pills.
• Mini-pill have a contraceptive effect.
• IUD: a contraceptive device fitted inside the uterus and physically preventing the implantation of fertilized ova.
• Contraceptive pills prevent the development of the endometrium that becomes unsuitable for the implantation.
• mini-pill have small dose of progesterone
• mini-pill inhibits ovulation less efficeintly
• mini-pill keeps the cervical mucus impermeable for the sperm
• mini-pill mkaes the endometrium unsuitable for implantation