UNIT+7-+EMBRYOLOGY

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1. What are stem cells and how do they reproduce? Stem cells are cells with the potential to develop into many different cell types in the body. Stem cells reproduce by dividing and renewing themselves for long periods. 2. Compare oogenesis and spermatogenesis? Oogenesis makes eggs and spermatogenesis makes sperms. Place the following words in chronological order and then define the words. 1 Fertilization 6 Implantation 2 Zygote 7 Gastrulation 3 cleavage 8 Gastrula 4 morula 9 Embryo 5 blastula 10 Fetus 3. Describe the functions of the male and female reproductive systems. The main function of the male reproductive system is to produce and deliver sperm. The main function of the female reproductive system is to produce ova. In addition, the female reproductive system prepares the female's body to nourish a developing embryo. 4. What happens during each of the four phases of the menstrual cycle? The menstrual cycle has four phases: follicular phase, ovulation, luteal phase, and menstruction 5. What is zygote? A fertilized egg 6. What is the role of the placenta? The placenta is the embryo’s organ of respiration, nourishment, and excretion. 7. What is neurulation? The development of the nervous system. 8. What are the differences between identical twins and fraternal twins? Identical twins are monozygotic which 1 egg split. Fraternal twins are dizygotic which two eggs. 9. What is Ectoderm, Mesoderm, and Endoderm? Ectoderm-skin, nervous system Mesoderm-organs,muscles,bone Endoderm-glands, thyroid, liver 10. What are these mitotitic cell divisions called? cleavages ||

Vocabulary: Embryology 1. zygote: is a cell that is the result of fertilization 2. Blastocyst: is the structure formed in early embryogenesis, after the formation of the blastocoel, but before implantation. -trophoblast: are cells forming the outer layer of a blastocyst, which provide nutrients to the embryo and develop into a large part of the placenta. They form during the first stage of the pregnancy -Inner cell mass: also known as the embryoblast or pluriblast; is the mass of cells inside the primordial embryo that will eventually give rise to the definitive structures of the fetus. - blastocoele: is the fluid-filled central region of a blastocyst. A blastocoele forms during embryogenesis when a zygote (a fertilized ovum) divides into many cells through mitosis. 3. Gastrulation: is a phase early in the development of animal embryos, during which the morphology of the embryo is dramatically restructured by cell migration. 4. Ectoderm: gives rise to the digestive organs, lungs and bladder 5. Mesoderm: gives rise to the muscles, skeleton and blood system. 6. Endoderm: gives rise to the nervous system and skin. 7. Implantation: is an event that occurs early in pregnancy in which the embryo adheres to the wall of uterus. 8. Chorion: is one of the membranes that exists during pregnancy between the developing fetus and mother. Surrounds the embryo and other membranes. 9. Amniotic sac: is the sac in which the fetus develops 10. Placenta: develops from the same sperm and egg cells that form the fetus, and functions as a foetomaternal organ with two components, the foetal part (Chorion frondosum), and the maternal part (Decidua basailis). 11. Blastomere (cleavage) stage: is a type of cell produced by division of the egg after fertilization. -2-cell stage: When the zygot splits into 2-cells - 4-cell stage: when the two cells splits into 4-cells -Morula: is an embryo at an early stage of embryonic development, consisting of approximately 12-32 cells 12. Zona Pellucida: is a glycoprotein membrane surrounding the plasma membrane of an oocyte. 13. Fertilization (1st stage): the point at which human life begins -Female pronucleus: is the nucleus of a sperm or an egg cell during the process of fertilization, after the sperm enters the ovum, but before they fuse. - Male Pronucleus: is the nucleus of a sperm or an egg cell during the process of fertilization, after the sperm enters the ovum, but before they fuse 14. Monozygotic: frequently referred to as identical twins, occur when a single egg is fertilized to form one zygote (monozygotic) which then divides into two separate embryos. 15. dizygotic: commonly known as fraternal twins, but also referred to as non-identical twins or biovular twins) usually occur when two fertilized eggs are implanted in the uterine wall at the same time. 16. Amniotic fluids: is the nourishing and protecting liquid contained by the amnion of a pregnant woman. 17. Fetus: is a developing mammal or other viviparous vertebrate, after the embryonic stage and before birth. 18. Amnion: is a membranous sac that surrounds and protects the embryo. 19. Embryo: is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination. 20. Sperm: Sperm cells cannot divide and have a limited life span, but they can fuse with egg cells during fertilization to form a totipotent zygote with the potential to develop into a new organism. 21. spermatogenesis: is the process by which male spermatogonia develop into mature spermatozoa. Spermatozoa are the mature male gametes in many sexually reproducing organisms.

For more vocab and videos explaining embryology go to http://cna.uc.edu/embryology/ this website was very helpful....