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{{WBRQuestion | {{WBRQuestion | ||
|QuestionAuthor={{Rim | |QuestionAuthor={{Rim}} | ||
|ExamType=USMLE Step 1 | |ExamType=USMLE Step 1 | ||
|MainCategory=Physiology | |MainCategory=Physiology | ||
| Line 20: | Line 20: | ||
|MainCategory=Physiology | |MainCategory=Physiology | ||
|SubCategory=Reproductive | |SubCategory=Reproductive | ||
|Prompt=A couple | |Prompt=A couple is trying to conceive a child for 5 years. During their visit to the in-vitro fertilization (IVF) center, the physician informs the family that during IVF, the embyro is directly implanted in the uterus. In a normal pregnancy, at which day post-fertilization does an embryo undergoes implantation in the uterus? | ||
|Explanation=During a normal pregnancy, fertilization | |Explanation=During a normal pregnancy, fertilization is considered to occur at day 0. The fertilization process typically occurs in the ampullary-ischmic junction of the fallopian tubes. Soon after fertilization occurs, the oocyte proceeds with the meiosis II that had been arrested after ovulation. The fertilized egg continues to descend along the fallopian tube as mitosis of the embryo progressively occurs to become a morula on day 3 and a blastocyst on day 5. On day 6, the blastocyst reaches the endometrium and implantation starts. Soon after implantation takes place, hCG is secreted and pregnancy then becomes detectable by serum and urinary concentrations of hCG within 10-14 days post-fertilization. | ||
Educational Objective: Typically, blastocyst implantation occurs on day 6 post-fertilization | |||
|AnswerA=Day 2 | |AnswerA=Day 2 | ||
|AnswerAExp=On day 2, the zygote is still within the fallopian tubes and has not descended to the level of the endometrium. | |AnswerAExp=On day 2, the zygote is still within the fallopian tubes and has not descended to the level of the endometrium. | ||
|AnswerB=Day 4 | |AnswerB=Day 4 | ||
|AnswerBExp=On day 4, the morula is still within the fallopian tubes and has not descended to the level of the endometrium. | |AnswerBExp=On day 4, the morula is still within the fallopian tubes and has not descended to the level of the endometrium. | ||
|AnswerC=Day 6 | |AnswerC=Day 6 | ||
|AnswerCExp=On day 6, the blastocyst is in the endometrium and implantation | |AnswerCExp=On day 6, the blastocyst is in the endometrium and implantation starts. | ||
|AnswerD=Day 10 | |AnswerD=Day 10 | ||
|AnswerDExp= | |AnswerDExp=On day 10, the beginning of implantation already occurred and hCG is secreted. | ||
|AnswerE=Day 12 | |AnswerE=Day 12 | ||
|AnswerEExp=On day 12, implantation already | |AnswerEExp=On day 12, the beginning of implantation already occurred and hCG is secreted. | ||
|RightAnswer=C | |RightAnswer=C | ||
|WBRKeyword=day 6, implantation, blastocyst, morula, secretion, hCG, zygote, fertilization, egg, oocyte, sperm, endometrium, uterus, IVF | |WBRKeyword=day, 6, implantation, blastocyst, morula, secretion, hCG, zygote, fertilization, ampulla, isthmus, junction, egg, oocyte, sperm, endometrium, uterus, IVF | ||
|Approved= | |Approved=No | ||
}} | }} | ||
Revision as of 17:47, 6 November 2014
| Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Physiology |
| Sub Category | SubCategory::Reproductive |
| Prompt | [[Prompt::A couple is trying to conceive a child for 5 years. During their visit to the in-vitro fertilization (IVF) center, the physician informs the family that during IVF, the embyro is directly implanted in the uterus. In a normal pregnancy, at which day post-fertilization does an embryo undergoes implantation in the uterus?]] |
| Answer A | AnswerA::Day 2 |
| Answer A Explanation | AnswerAExp::On day 2, the zygote is still within the fallopian tubes and has not descended to the level of the endometrium. |
| Answer B | AnswerB::Day 4 |
| Answer B Explanation | AnswerBExp::On day 4, the morula is still within the fallopian tubes and has not descended to the level of the endometrium. |
| Answer C | AnswerC::Day 6 |
| Answer C Explanation | AnswerCExp::On day 6, the blastocyst is in the endometrium and implantation starts. |
| Answer D | AnswerD::Day 10 |
| Answer D Explanation | AnswerDExp::On day 10, the beginning of implantation already occurred and hCG is secreted. |
| Answer E | AnswerE::Day 12 |
| Answer E Explanation | AnswerEExp::On day 12, the beginning of implantation already occurred and hCG is secreted. |
| Right Answer | RightAnswer::C |
| Explanation | [[Explanation::During a normal pregnancy, fertilization is considered to occur at day 0. The fertilization process typically occurs in the ampullary-ischmic junction of the fallopian tubes. Soon after fertilization occurs, the oocyte proceeds with the meiosis II that had been arrested after ovulation. The fertilized egg continues to descend along the fallopian tube as mitosis of the embryo progressively occurs to become a morula on day 3 and a blastocyst on day 5. On day 6, the blastocyst reaches the endometrium and implantation starts. Soon after implantation takes place, hCG is secreted and pregnancy then becomes detectable by serum and urinary concentrations of hCG within 10-14 days post-fertilization.
Educational Objective: Typically, blastocyst implantation occurs on day 6 post-fertilization |
| Approved | Approved::No |
| Keyword | WBRKeyword::day, WBRKeyword::6, WBRKeyword::implantation, WBRKeyword::blastocyst, WBRKeyword::morula, WBRKeyword::secretion, WBRKeyword::hCG, WBRKeyword::zygote, WBRKeyword::fertilization, WBRKeyword::ampulla, WBRKeyword::isthmus, WBRKeyword::junction, WBRKeyword::egg, WBRKeyword::oocyte, WBRKeyword::sperm, WBRKeyword::endometrium, WBRKeyword::uterus, WBRKeyword::IVF |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |