Exam 2 Review Human Reproductive Technology in the 21st Century Chapter 1 When Does Human Life Begin What is the correct order of the stages of development Pronuclear fusion of sperm and egg Cleavage Degradation of the Zona Pellucida Implantation The First Week Fertilization and Pre Implantation I A The meeting of two gametes creates a unique combination of genes 1 Zygote 2 Match the cell to its chromosome karyotype Sperm cell Egg cell and Diploid Zygote A new individual at the one cell stage Sperm 22 autosomes 1 X or 1 Y sex chromosome i ii Egg cell 22 autosomes 1 X sex chromosome iii Zygote 44 autosomes 2 X or 1 X and 1 Y sex chromosome B Cleavage After fertilization the process of early cell divisions in the development process 1 Once the blastocyst is formed it consists of approximately 100 cells in which 30 34 cells are called the inner cell mass located in the blastocoel while 66 70 cells surround the inner cell mass termed the trophoblast Keep in mind that the ICM cells create the embryo while the cells from the trophoblast create the placenta C Implantation the process where the blastocyst clings itself to the mother s uterus and buries itself into the uterine lining 1 2 Once ovulation begins the egg will be fertilized in the oviduct then proceeds to be divide After six days following the start of fertilization blastocysts are formed through the cleavage process i This results in the formation of the morula and blastocyst 3 Once the embryo hatches from its shell called the zona pellucida the sperm must get through the zona pellucida i If the embryo impants itself before it reaches the uterus it can create a life threatening situation for the mother termed a Tubal Pregnancy 4 Catholicism and Hinduism are the two religious beliefs that consider conception the first II stage of human life Post Implantation The First Trimester During the first trimester four processes occur Morphogenesis differentiation of trophoblast gastrulation and germ layer formation 1 The three germ layers include Ectoderm skin and nerves Mesoderm muscle blood blood vessels and Endoderm gut pancreas liver kidneys 2 Gastrulation the process where differentiation of the embryo begins It also is when germ layers and germ cells form i In which the ICM creates the cells of the embryo and is the collection of pluripotent cells have the potential to become any cell of the body A Once Gastrulation Begins 1 Identical twins are formed by the splitting of an embryo while fraternal twins are the result of the fertilization of more than one egg B Organogenesis the process where organs are formed using the instructions that resulted from gastrulation C Fetus 1 Organisms are considered embryo s at the time of fertilization while organisms are considered fetus eight weeks after fertilization 2 The fetus can be born and survive in the third trimester 27 38 weeks 1 Primary sex characteristics are the internal gonads while the secondary sex D Sex Determination characteristics are external E Consciousness 1 Brainwave activity in the fetus usually begins around week 25 Chapter 2 Fertilization and Assisted Reproduction I Louise Brown 1 Brown was the first test tube baby as she was conceived on July 25 1978 Problems with Reproduction II A Gametogenesis the process of undertaking meiosis to make eggs or sperm Know the diagrams of a sperm cell and an egg cell B Fertilization 1 The process of fertilization is localization penetration prevention of polyspermy fusion of genetic material and initiating development 2 When the sperm penetrates the egg i ii iii iv v vi A female reproductive tract initiates the sperm The sperm binds to the zona pellucida An acrosomal reaction occurs The sperm lyses a hole in the zona pellucida Fusion of the sperm and egg membranes occurs The sperm pronucleus enters the egg cytoplasm C In vitro fertilization Medical Issues and Moral Dilemmas 1 Multiple births tubal pregnancy kidney and ovary damage are all possible risks 2 Human embryonic stem cells come from an excess of unused embryos during IVF 3 The U S policy on federal funding for human embryonic stem cell research is as follows i Embryos derived from IVF clinics are either discarded donated with no compensation or donated with consent of parents Chapter 3 Embryonic Stem Cells I Adult vs Embryonic Stem Cells 1 Adult cells maintain our tissues after the tissues have formed while ESC s 2 pluripotent are able to regenerate any tissue of the body Induced Pluripotent Stem Cells a normal cell that was manipulated to become a pluripotent cell 3 ESC s are created from the remaining embryos after a successful IVF Chapter 4 Human Cloning I Dolly 1 The first nuclear transplant experiments were performed with frog eggs and were intended to test genomic equivalence i The cloning of Dolly was the great advance with cloning technology A Reproductive vs Therapeutic Cloning 1 Therapeutic cloning the production of genetically identical blastocyst 2 Reproductive cloning complete copy of human being put in uterus and carried to term 3 During the process of cloning the oocyte is taken from the mother or donor and the genetic information is removed Then the nuclei from the person of interest is inserted into the egg Chapter 5 Reproductive Engineering Engineering the Human Germline I A Somatic Cell Gene Therapy 1 Somatic reinserts genetically modified cells temporarily into the patient 2 Reproductive gene therapy permanently genetically engineers individuals before they are conceived B Reproductive Gene Therapy C Human Human Chimeras 1 Human gene therapy healthy gene is introduced into the patient s body cells through a virus vector to hopefully cure the disease isn t 100 1 A transgenic animal an animal that has undergone gene therapy 2 Chimera embryos that consist of cells from two or more individuals
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