Miscellaneous+Repro.+Topics+HW3+MC

Miscellaneous Repro. Topics SCI Human Biology - 1 Assigned: 11/3 Due: 11/4 Miscellaneous Reproduction Topics

(1) What does IVF stand for? What does it treat? How does the doctor get the eggs? Where are the embryo’s made and when are they implanted? Where are they implanted? (p.334) IVF stands for In Vitro Fertilization. During IVF, conception occurs in laboratory glassware. Ultrasound machines can now spot follicles in the ovaries that hold immature eggs; therefore, the latest method is to forgo the administration of fertility drugs and retrieve immature eggs by using a needle. The immature eggs are then brought to maturity in glassware, and then concentrated sperm are added. After about two to four days, the embryos are ready to be transferred to the uterus of the woman, who is now in the secretory phase of her uterine cycle. If desired, the embryos can be tested for a genetic disease, and only those found to be free of disease will be used. If implantation is successful, development is normal and continues to term.

(2) Embryos that are not implanted are frozen. What can happen to frozen embryos? (p.335) Most are not likely to survive. They are donated to other couples. Sometimes the clinics might not be able to contact the couple for whom the frozen embryos were produced. The estimated high numbers of stored frozen embryos has generated debate about their fate, complicated by the fact that the long-term viability of frozen embryos is not well understood.

(3) What is an ectopic pregnancy? (p. 357) It’s an implantation of the embryo in a location other than the uterus, most often in an oviduct. This happens during the second week of embryonic development.

(4) Briefly describe how cloning is done. (p. 362) The donor nucleus contains DNA. You remove and discard eggs nucleus to fuse the egg with the donated nucleus. An electric shock triggers cell divisions. An embryo begins to develop in vitro. The embryo is implanted into surrogate mother. Then the clone is born.

(5) What are some of the problems that have developed in cloned animals? (p. 362) malfunctioning livers, abnormal blood vessels and heart problems, underdeveloped lungs, diabetes, immune system deficiencies are al seen in newborns. Several cow clones had head deformities.

(6) What is the difference between reproductive cloning and therapeutic cloning? What are the pros and cons of each. (p. 362) In reproductive cloning, the desired end is an individual. In therapeutic cloning, the desired end is not an individual; rather it is the embryonic cells that possibly can be “coaxed” into becoming various types cells. The purpose of therapeutic cloning is to learn more about how specialization of cells occurs and to provide cells and tissues that could be used to treat human illness, such as diabetes, spinal cord injuries, Parkinson disease, and so forth. In the U.S., investigators can use only embryonic stem cell lines that already exist and cannot start new ones because of ethical concerns. However, researchers can freely make use of adult stem cells that reside in most tissues of the body. Investigators have been able to isolate adult stem cells and use them to regenerate verve tissue for the treatment of Parkinson disease, for example.

(7) When can you tell if an embryo is a boy or girl? (p. 364) At six weeks, a small bud appears between the legs; this can develop into the male penis or the female clitoris. At nine weeks, a urogenital groove bordered by two swellings appears. By 14 weeks, this groove has disappeared in males, and the scrotum has formed from the original swellings.

(8) Describe two causes of cases where a person is XY (male) but looks and acts female. (p. 365) In individuals with the XY female syndrome, a piece of the Y chromosome is missing. In individuals with the XX male syndrome, this same small piece is present on an X chromosome. The piece of a Y chromosome that causes male genitals to develop is called the SRY gene. It causes testes to form and then the testes secrete these hormones: Testosterone, Anti-Mullerian, and Dihydrotestosterone.

(9) What is true hermaphroditism? (p. 365) It’s when a person has both ovarian and testicular tissue. That’s very rare though. The clitoris looks like a penis; the voice deepens, and muscles enlarge. There is no breast development, and the individual does not menstruate. The individual has testes but appears to be a normal female until puberty.The testes never produce testosterone or dihydrotestosterone.

(10) What is stage 3 of birth? What happens? (p. 369) The placenta, or afterbirth, is delivered during the third stage of parturition. About 15 minutes after delivery of the baby, uterine muscular contractions shrink the uterus and dislodge the placenta. The placenta then is expelled into the vagina. As soon as the placenta and its membranes are delivered, the third stage of parturition is complete.