WBR0884: Difference between revisions
Jump to navigation
Jump to search
No edit summary |
Sergekorjian (talk | contribs) No edit summary |
||
| Line 1: | Line 1: | ||
{{WBRQuestion | {{WBRQuestion | ||
|QuestionAuthor={{ | |QuestionAuthor={{SSK}} (Reviewed by Serge Korjian) | ||
|ExamType=USMLE Step 1 | |ExamType=USMLE Step 1 | ||
|MainCategory=Embryology | |MainCategory=Embryology | ||
| Line 21: | Line 21: | ||
|MainCategory=Embryology | |MainCategory=Embryology | ||
|SubCategory=Musculoskeletal/Rheumatology | |SubCategory=Musculoskeletal/Rheumatology | ||
|Prompt=A 4 year old boy is brought to the pediatrics clinic for his regular well baby check-up. The child seems to be developing well and has not missed any of his milestones so far. His physical exam | |Prompt=A 4-year-old boy is brought to the pediatrics clinic for his regular well baby check-up. The child seems to be developing well and has not missed any of his milestones so far. His physical exam is unremarkable except for a persistent soft spot on the skull suspicious for delayed closure of the fontanelles. Which of the following tissues share the same embryologic origin with the bones responsible for fontanelle closure? | ||
|Explanation=The bones of the skull, unlike the rest of the skeletal system, are derived from neural crest cells. Other bones are generally derived from the mesodermal layer. Other derivatives of neural crest cells include: | |Explanation=Anterior fontanelles typically close between 4 months and 2 years, half of which occur in the first year. The bones of the skull, unlike the rest of the skeletal system, are derived from neural crest cells. Other bones are generally derived from the mesodermal layer. Other derivatives of neural crest cells include: | ||
<li> Chromaffin cells of the adrenal medulla | <li> Chromaffin cells of the adrenal medulla | ||
<li> Parafollicular C cells of the thyroid | <li> Parafollicular C cells of the thyroid | ||
<li> Schwann cells | <li> Schwann cells | ||
<li> Cranial nerves | <li> Cranial nerves | ||
<li> Majority of ANS | <li> Majority of ANS | ||
<li> Odontoblasts | <li> Odontoblasts | ||
| Line 33: | Line 33: | ||
<li> Melanocytes | <li> Melanocytes | ||
<li> Celiac ganglion | <li> Celiac ganglion | ||
|AnswerA=Arachnoid mater | |AnswerA=Arachnoid mater | ||
|AnswerAExp=The arachnoid mater is derived from neural crest cells similar to the bones of the skull. | |AnswerAExp=The arachnoid mater is derived from neural crest cells similar to the bones of the skull. | ||
| Line 45: | Line 44: | ||
|AnswerEExp=The anterior pituitary is derived from surface ectoderm. | |AnswerEExp=The anterior pituitary is derived from surface ectoderm. | ||
|EducationalObjectives=Both the arachnoid mater and the bones of the skull are derived from the neural crest cells. | |EducationalObjectives=Both the arachnoid mater and the bones of the skull are derived from the neural crest cells. | ||
|References= | |References=Crane JF, Trainor PA. Neural crest stem and progenitor cells. Annu Rev Cell Dev Biol. 2006;22(1):267-86.<br> | ||
Aisenson MR. Closing of the anterior fontanelle. Pediatrics. 1950;6(2):223-6.<br> | |||
First Aid 2014 page 553 <br> | |||
|RightAnswer=A | |RightAnswer=A | ||
|WBRKeyword=Embryologic derviatives, | |WBRKeyword=Embryologic derviatives, Neural crest cells, Bones of the skull, Arachnoid mater, fontanelles | ||
|Approved=No | |Approved=No | ||
}} | }} | ||
Revision as of 17:09, 9 March 2015
| Author | [[PageAuthor::Serge Korjian M.D. (Reviewed by Serge Korjian)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Embryology |
| Sub Category | SubCategory::Musculoskeletal/Rheumatology |
| Prompt | [[Prompt::A 4-year-old boy is brought to the pediatrics clinic for his regular well baby check-up. The child seems to be developing well and has not missed any of his milestones so far. His physical exam is unremarkable except for a persistent soft spot on the skull suspicious for delayed closure of the fontanelles. Which of the following tissues share the same embryologic origin with the bones responsible for fontanelle closure?]] |
| Answer A | AnswerA::Arachnoid mater |
| Answer A Explanation | AnswerAExp::The arachnoid mater is derived from neural crest cells similar to the bones of the skull. |
| Answer B | AnswerB::Skeletal muscles |
| Answer B Explanation | AnswerBExp::Skeletal muscles are derived from mesoderm unlike the bones of the skull which are dervied from neural crest cells. |
| Answer C | AnswerC::Kidneys |
| Answer C Explanation | AnswerCExp::the kidneys are also derived from mesoderm. |
| Answer D | AnswerD::Retina |
| Answer D Explanation | AnswerDExp::The retina is derived from neuroectoderm. |
| Answer E | AnswerE::Anterior pituitary |
| Answer E Explanation | AnswerEExp::The anterior pituitary is derived from surface ectoderm. |
| Right Answer | RightAnswer::A |
| Explanation | [[Explanation::Anterior fontanelles typically close between 4 months and 2 years, half of which occur in the first year. The bones of the skull, unlike the rest of the skeletal system, are derived from neural crest cells. Other bones are generally derived from the mesodermal layer. Other derivatives of neural crest cells include:
Educational Objective: Both the arachnoid mater and the bones of the skull are derived from the neural crest cells. References: Crane JF, Trainor PA. Neural crest stem and progenitor cells. Annu Rev Cell Dev Biol. 2006;22(1):267-86. Aisenson MR. Closing of the anterior fontanelle. Pediatrics. 1950;6(2):223-6. First Aid 2014 page 553 ]] |
| Approved | Approved::No |
| Keyword | WBRKeyword::Embryologic derviatives, WBRKeyword::Neural crest cells, WBRKeyword::Bones of the skull, WBRKeyword::Arachnoid mater, WBRKeyword::fontanelles |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |