*NURSING > EXAM REVIEW > OB StudyGuide Chapters 10-12. NURS 3360 (All)

OB StudyGuide Chapters 10-12. NURS 3360

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Chapter 10 1. Regarding fertilization: successful fusion of gametes to form a new organism a. Fertilization takes place in the outer third of the ampulla of the fallopian tube b. What does it invol ... ve? The union of ovum is fertilized by the sperm, making a zygote & is the start point of pregnancy. c.How does it happen? - Sperm attraction to the egg- through chemotaxis - Acrosomal reaction- once the sperm physically contacts the egg causes exocytosis of the outside of the egg. This releases enzymes that digest a path to the eggs surface. - Once the sperm has dissolved its way into the egg it binds to the egg - Ovum is released from ovary & travels through the fallopian tube; sperm travel 7 inches through the vagina to meet the egg & penetrates the outer membrane of the ovum 2. Regarding implantation: 310 a. Ideally where does it take place? In the upper uterus (fundus), where a rich blood supply is available. b. How long does it take (in days) from conception to implantation? 7 to 10 days after conception in the endometrium c.hat are all those little cell balls called? How are they different? Morula: 16 cells appear as solid ball of cells; “little mulberry”; forms after series of four cleavages in mitosis.  Blastocyst: morula divides into specialized cells; hollow ball of cells; inner surface forms embryo & amnion  Trophoblast: outer layer of blastocyst cavity; develops into chorion & helps form placenta 3. Regarding differentiation (When less specialized cells become more specialized): What happens after implantation? Concurrent with the development of the trophoblast & implantation, further differentiation of the inner cell mass occurs. Some of the cells become the embryo, & others give rise to the membranes that surround & protect it. The three embryonic layers of cells formed are: 1. Ectoderm—forms the central nervous system, special senses, skin, & glands 2. Mesoderm—forms the skeletal, urinary, circulatory, & reproductive organs 3. Endoderm—forms the respiratory system, liver, pancreas, & digestive system [Show More]

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