Exam 5 Review:  Chapter 27 Contraception

conception - The formation of a viable diploid zygote by the union of the haploid games, the male sperm and the female ovum; the successful fertilization of the female ovum by the male sperm; ideally, it should occur in the upper third of the oviduct in order for sufficient development of the conceptus to occur so that successful implantation in the uterine wall is also likely to occur.

contraception - The intentional prevention of conception or impregnation, either for a temporary period of time or permanently, through the use of various devices, agents, drugs, sexual practices, or surgical procedures.  Nickname -- birth control.  [See examples below.]

sterilization - The intentional prevention of conception or impregnation, usually permanently, through the use of various devices, agents, drugs, sexual practices, or surgical procedures.

tubal ligation -  A surgical method of female sterilization, often performed laparoscopically, in which the oviducts = uterine tubes are surgically tied in two places and the tubes removed in between the ligations; estimated to be better than 99% effective.

oral contraceptives - Any of the drug preparations which can be taken by mouth and designed to prevent conception or impregnation; most preparations consist of a set pills with varying doses of progesterone (more) and estrogen (less) which are taken on a 28 day cycle; those pills taken during the middle of the cycle have hormone levels which mimic the levels of progesterone and estrogens present during a pregnancy; as a result, negative feedback inhibition of GnRH from the hypothalamus and FSH and LH from the anterior pituitary occur; the loss of appropriate control stimuli from the anterior pituitary cause impaired follicular development and failure of ovulation while at the same time altering the quality of the cervical mucus and making the endometrium less receptive to implantation; these drugs may also be used to treat problems in the menstrual cycle and to prevent ovarian cyst formation; side effects include increased risk for heart attack and stroke in women who smoke and drink.

intrauterine device (IUD) -  A birth control device, e.g., a plastic or metallic loop, ring, or spiral, which is inserted into the uterus through the cervical opening to prevent implantation by mechanical irritation of the endometrium and myometrium; side effects include risk of pelvic inflammatory disease, infertility, and excessive menstrual bleeding and pain.

condom - A flexible nonporous sheath, usually made of thin rubber or latex, designed to cover the penis during sexual intercourse for contraceptive purposes or as a means of preventing sexually transmitted diseases.  aka -- prophylactic (device); the only method of contraception likely to prevent STDs.

vaginal pouch = female condom - A loose-fitting polyurethane sheath closed at one end, which is inserted intravaginally before sexual intercourse for contraceptive purposes or as a means of preventing sexually transmitted diseases; the only method of contraception likely to prevent STDs.

diaphragm = cervical cap - A contraceptive device consisting of a thin flexible disk, usually made of rubber, which is designed to cover the uterine cervix to prevent the entry of sperm during sexual intercourse; some are filled with spermicidal agents to increase the success rate.

rhythm method -  A birth-control method dependent on refraining from intercourse, abstinence, during the period when ovulation is most likely to occur; the method somewhat arbitrarily estimates this period by noting days on the calendar relative to the times of menses over time, which does not adequately take into account the irregularity of individual cycles.

sympto-thermal method -  A birth-control method dependent on refraining from intercourse, abstinence, during the period when ovulation is most likely to occur; the method requires the observation of the symptoms of ovulation and noting the female's morning temperature to estimate the fertile and infertile days of the woman's menstrual cycle.

induced abortion - Any of various procedures, using surgery or hormone drugs, which result in termination of pregnancy and expulsion of the products of conception or an embryo or of a fetus which is incapable of survival.

RU 486 (mifepristone) - A drug which acts as a progestational and glucocorticoid antagonist; its inhibition of progesterone receptors induces endometrial bleeding during the luteal phase and in early pregnancy by releasing endogenous prostaglandins from the endometrium or decidua; this bleeding can interfere with the successful initiation of placenta formation to support a developing embryo; therefore, it can be used to prevent pregnancy after intercourse; as a glucocorticoid receptor antagonist, it has been used to treat hypertension in patients with nonpituitary Cushing's syndrome.  nickname -- the morning-after pill.

List:

2. the various methods of birth control and explain their physiological basis.

Birth Control Method	Physiological Basis
tubal ligation	exclude spermatozoans from semen in the ejaculate
oral contraceptives	prevent ovulation
intrauterine device (IUD)	prevent or disrupt implantation
condom	prevent gametes from meeting, i.e., prevent fertilization
vaginal pouch = female condom	exclude spermatozoans from the uterus and uterine tubes
diaphragm = cervical cap	exclude spermatozoans from the uterus and uterine tubes
rhythm method	reduces probability that gametes will meet, i.e., prevent fertilization
sympto-thermal method	reduces probability that gametes will meet, i.e., prevent fertilization
induced abortion	physically removes embryo from uterus to end development
RU 486 (mifepristone)	prevent or disrupt implantation
abstinence	reduces probability that gametes will meet, i.e., prevent fertilization