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(Created page with "{{WBRQuestion |QuestionAuthor={{Rim}} |ExamType=USMLE Step 1 |MainCategory=Physiology |SubCategory=Reproductive |MainCategory=Physiology |SubCategory=Reproductive |MainCategor...")
 
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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor={{Rim}}, {{AJL}} {{Alison}}
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Physiology
|MainCategory=Physiology
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|MainCategory=Physiology
|MainCategory=Physiology
|SubCategory=Reproductive
|SubCategory=Reproductive
|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?
|Prompt=A couple, trying to conceive a child for 5 years, visits 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 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.
|Explanation=During a normal pregnancy, fertilization occurs at day 0. The fertilization process typically occurs in the ampullary-ischmic junction of the fallopian tubes. Soon following fertilization, 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, becoming a morula on day 3 and a blastocyst on day 5. On day 6, the blastocyst reaches the endometrium and implantation is initiated. The pregnancy becomes detectable by serum and urinary concentrations of hCG within 10-14 days post-fertilization.
 
|EducationalObjectives= Typically, blastocyst implantation occurs on day 6 post-fertilization.
|References=  First Aid 2014 page 552


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 starts.
|AnswerCExp=On day 6, the blastocyst is in the endometrium and implantation begins.
|AnswerD=Day 10
|AnswerD=Day 10
|AnswerDExp=On day 10, the beginning of implantation already occurred and hCG is secreted.
|AnswerDExp=By day 10, implantation already started and hCG is being secreted.
|AnswerE=Day 12
|AnswerE=Day 12
|AnswerEExp=On day 12, the beginning of implantation already occurred and hCG is secreted.
|AnswerEExp=On day 12, implantation already started and hCG is being secreted.
|RightAnswer=C
|RightAnswer=C
|WBRKeyword=day, 6, implantation, blastocyst, morula, secretion, hCG, zygote, fertilization, ampulla, isthmus, junction, egg, oocyte, sperm, endometrium, uterus, IVF
|WBRKeyword=day 6, implantation, blastocyst, morula, secretion, hCG, zygote, fertilization, egg, oocyte, sperm, endometrium, uterus, IVF, pregnancy, meiosis, mitosis, reproduction
|Approved=No
|Approved=Yes
}}
}}

Revision as of 14:46, 30 July 2014

 
Author [[PageAuthor::Rim Halaby, M.D. [1], Alison Leibowitz [2] (Reviewed by Alison Leibowitz)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Physiology
Sub Category SubCategory::Reproductive
Prompt [[Prompt::A couple, trying to conceive a child for 5 years, visits 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 begins.
Answer D AnswerD::Day 10
Answer D Explanation AnswerDExp::By day 10, implantation already started and hCG is being secreted.
Answer E AnswerE::Day 12
Answer E Explanation AnswerEExp::On day 12, implantation already started and hCG is being secreted.
Right Answer RightAnswer::C
Explanation [[Explanation::During a normal pregnancy, fertilization occurs at day 0. The fertilization process typically occurs in the ampullary-ischmic junction of the fallopian tubes. Soon following fertilization, 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, becoming a morula on day 3 and a blastocyst on day 5. On day 6, the blastocyst reaches the endometrium and implantation is initiated. The pregnancy 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.
References: First Aid 2014 page 552]]

Approved Approved::Yes
Keyword WBRKeyword::day 6, WBRKeyword::implantation, WBRKeyword::blastocyst, WBRKeyword::morula, WBRKeyword::secretion, WBRKeyword::hCG, WBRKeyword::zygote, WBRKeyword::fertilization, WBRKeyword::egg, WBRKeyword::oocyte, WBRKeyword::sperm, WBRKeyword::endometrium, WBRKeyword::uterus, WBRKeyword::IVF, WBRKeyword::pregnancy, WBRKeyword::meiosis, WBRKeyword::mitosis, WBRKeyword::reproduction
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