ECPI: ANATOMY & PHYSIOLOGY 2: CHAPTER 23: PREGNANCY Exam Question With Correct Answers

ECPI: ANATOMY & PHYSIOLOGY 2: CHAPTER 23: PREGNANCY Exam Question With Correct Answers Cleav- - Answer - -To divide Post- - Answer - -Behind, after, later Pre- - Answer - -Before Troph- - Answer - -Organism obtaining its food in a specified way How does pregnancy begin? - Answer - -Sperm and secondary oocyte unite in fertilization, forming a zygote, pregnancy begins How does fertilization takes place? - Answer - -- Union of secondary oocyte and sperm cell - Oocyte survives 12-24 hours after ovulation Sperm Cells Joining Secondary Oocyte: - Answer - -- Sperm first invades corona radiata (layers of follicular cells that surround oocyte), dissolving it with acrosomal enzymes - Sperm digest the zona pellucida (glycoprotein layer closes to secondary oocyte) - Only 1 sperm will actually penetrate oocyte's membrane and fertilize it - As sperm nucleus enters oocyte, secondary oocyte completes meiosis II, producing tiny polar body and alarge cell that contains a nucleus with a female's genetic contribution - Pronuclei now unite to form a zygote (fertilized egg) containing 46 chromosomes Pregnancy & Prenatal Period: - Answer - -- 3 trimesters (each about 3 months) Prenatal period divided into 2 stages: - Embryonic stage - Fetal stage When can you detect a heartbeat in a fetus? - Answer - -5 weeks and 5 days Embryonic Stage: - Answer - -- From day 1 -- 8th week of pregnancy - Organogenesis (formation of organs) occurs - Starts placenta formation Fetal Stage: - Answer - -- 9th week -- 40th week - Organs just grow Zygote: - Answer - -- 12-24 hours after ovulation - Secondary oocyte fertilized, meiosis completed, zygote has 46 chromosomes Cleavage: - Answer - -- Rapid cell division and distribution of zygote's cytoplasm into progressively smaller cells - The cells produced are called: BLASTOMERES (cells that form morula) - Mitosis increases cell numbers - Divide without increasing cytoplasm in size Morula: - Answer - -Solid ball of 16 cells Blastocyst: - Answer - -- Hollow ball of cells that attaches to the endometrium of uterus - Implantation on 7th day after fertilization