What activity during oocyte activation prevents penetration by additional sperm? Also, after a sperm finds the ovum, list and briefly describe three main steps that have to occur, between the sperm and the ovum, that would lead to the moment of conception.

Anatomy and physiology

In-vitro fertilization occurs in the laboratory. The resulting embryos remain in a laboratory culture for up to six days before being transferred to the potential mother. If fertilization had occurred naturally (i.e., inside the female reproductive system instead of in-vitro), where would the embryo be and what developmental processes would it be undergoing during those first six days of development?

Reproductive physiology (human)     a) At the time of ovulation, the released ovum (egg) has completed both meiosis I and meiosis II.   b) Because the corpus luteum (CL) is rescued from atresia by hCG early in pregnancy, the CL continues to produce progesterone throughout the 9 months of a normal pregnancy.   c) Late in the follicular phase, estrogen participates in a positive feedback loop that leads to a surge in luteinizing hormone and ovulation.   d) Both (a) and (b) are correct and (c) is incorrect   e) Statements (a), (b) and (c) are all correct

Discuss the link between parturition and the initiation of lactation.

Describe the processes of fertilization and implantation

Use the following information to answer the next question. In order to initiate in vitro fertilization, a woman must undergo hormonal therapy to release numerous mature eggs and to prepare the uterine lining. The eggs are removed using a laparoscope and fertilized in a petri dish. The developing embryos are inserted back into the woman for implantation to take place. 13. What hormone changes would cause a female to develop and release a large number of mature eggs? A. Increased FSH and LH B. Decreased FSH and LH C. Increased estrogen and progesterone Decreased estrogen and progesterone D.

Describe in detail spermatogenesis

A couple living in Florida is trying to have a baby, but they are having trouble getting pregnant. The male is very light skinned yet enjoys spending as much time as possible outdoors in the sun. From the male's perspective, why might he be contributing to the trouble with getting pregnant? Excessive ultraviolet light exposure can reduce folate levels, and folate is required for normal sperm development. Excessive heat from the sunlight inhibits normal sperm production; thus, he probably does not have enough sperm. The male does not have enough melanin production to support normal sperm development. Excessive sunlight exposure can rapidly increase folate levels, which then inhibits normal sperm development. Normal sperm development occurs best in colder temperatures; thus, living in Florida he has a reduced chance of getting his partner pregnant.

What means to retain the ability to become any cell type—including germ-line cells and gametes—when exposed to the appropriate signals in a developing embryo?