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{{WBRQuestion
{{WBRQuestion
|QuestionAuthor={{Rim}}
|QuestionAuthor= {{YD}} (Reviewed by Serge Korjian)
|ExamType=USMLE Step 1
|ExamType=USMLE Step 1
|MainCategory=Histology
|MainCategory=Histology
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|MainCategory=Histology
|MainCategory=Histology
|SubCategory=Endocrine
|SubCategory=Endocrine
|MainCategory=Histology
|MainCategory=Histology
|MainCategory=Histology
|MainCategory=Histology
|MainCategory=Histology
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|MainCategory=Histology
|MainCategory=Histology
|SubCategory=Endocrine
|SubCategory=Endocrine
|Prompt=A scientist injects rats with insulin antibodies to induce experimental diabetes.
|Prompt=A scientist investigating a novel antidiabetic drug injects rats with insulin antibodies to induce experimental diabetes. Shown below is an image depicting the localization of the insulin antibodies by immunofluorescent microscopy.  The red color represents the insulin antibodies, the blue color represents the nuclei and the green color represents unspecific anti-mouse secondary antibody staining mostly the intercellular matrix.  To which of the following cells does the area in red most likely correspond to?<br>
[[File:Mouse pancreatic islet.jpg|400px]]
|Explanation=Hormones produced in the islets of Langerhans are secreted directly into the blood flow by (at least) five types of cells. In rat islets, endocrine cell subsets are distributed as follows:<br>


Shown below is an image depicting the localization of the insulin antibody by immunofluorescent microscopy.  Shown in red are the insulin antibodies and shown in blue are green unspecific anti-mouse secondary antibody staining mostly the intercellular matrix.  To which of the following cells does the area in red corresponds to?
*[[Alpha cells]] producing [[glucagon]] (15–20% of total islet cells)
[[File:Mouse pancreatic islet.jpg|300px]]
*[[Beta cells]] producing [[insulin]] and [[amylin]] (65–80%)- [[Delta cells]] producing [[somatostatin]] (3–10%)
|Explanation=Hormones produced in the islets of Langerhans are secreted directly into the blood flow by (at least) five types of cells. In rat islets, endocrine cell subsets are distributed as follows:
*[[Gamma cells]] or PP cells producing pancreatic polypeptide (3–5%)
 
*[[Epsilon cells]] producing [[ghrelin]] (<1%)
- [[Alpha cells]] producing [[glucagon]] (15–20% of total islet cells)
Since insulin is produced in the beta cells, the insulin antibodies will label the beta cells in red.
- [[Beta cells]] producing [[insulin]] and [[amylin]] (65–80%)
- [[Delta cells]] producing [[somatostatin]] (3–10%)
- [[Gamma cells]] or PP cells producing pancreatic polypeptide (3–5%)
- [[Epsilon cells]] producing [[ghrelin]] (<1%)
 
'''Educational objective:'''
The [[islets of langerhans]] are formed by different types of cells.  [[Beta cells]] occupy the center of the islet of langerhans and produce [[insulin]].
 
'''Reference:'''
First aid for USMLE step 1, (2013).  Page 287.
|AnswerA=Alpha cella
|AnswerA=Alpha cella
|AnswerAExp=[[Alpha cell]]s produce glucagon.  Alpha cells form 15–20% of the total number of cells of the [[islets of langerhans]].
|AnswerAExp=[[Alpha cell]]s produce glucagon.  Alpha cells form 15–20% of the total number of cells of the [[islets of langerhans]].
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|AnswerE=Epsilon cells
|AnswerE=Epsilon cells
|AnswerEExp=Epsilon cells produce ghrelin.  Epsilon cells form <1% of the total number of cells of the [[islets of langerhans]].
|AnswerEExp=Epsilon cells produce ghrelin.  Epsilon cells form <1% of the total number of cells of the [[islets of langerhans]].
|EducationalObjectives=The [[islets of langerhans]] are formed by different types of cells.  [[Beta cells]] occupy the center of the islet of langerhans and produce [[insulin]].
|References=Gomori, George. "Observations with differential stains on human islets of Langerhans." The American journal of pathology 17.3 (1941): 395.<br>
First Aid 2015 page 313
|RightAnswer=B
|RightAnswer=B
|WBRKeyword=Beta cells, insulin
|WBRKeyword=Beta cells, Insulin, Diabetes, Histology,
|Approved=No
|Approved=Yes
}}
}}

Latest revision as of 02:19, 28 October 2020

 
Author [[PageAuthor::Yazan Daaboul, M.D. (Reviewed by Serge Korjian)]]
Exam Type ExamType::USMLE Step 1
Main Category MainCategory::Histology
Sub Category SubCategory::Endocrine
Prompt [[Prompt::A scientist investigating a novel antidiabetic drug injects rats with insulin antibodies to induce experimental diabetes. Shown below is an image depicting the localization of the insulin antibodies by immunofluorescent microscopy. The red color represents the insulin antibodies, the blue color represents the nuclei and the green color represents unspecific anti-mouse secondary antibody staining mostly the intercellular matrix. To which of the following cells does the area in red most likely correspond to?

]]

Answer A AnswerA::Alpha cella
Answer A Explanation [[AnswerAExp::Alpha cells produce glucagon. Alpha cells form 15–20% of the total number of cells of the islets of langerhans.]]
Answer B AnswerB::Beta cells
Answer B Explanation [[AnswerBExp::Beta cells produce insulin and amylin. Beta cells form 65–80% of the total number of cells of the islets of langerhans.]]
Answer C AnswerC::Delta cells
Answer C Explanation [[AnswerCExp::Delta cells produce somatostatin. Delta cells form 3–10% of the total number of cells of the islets of langerhans.]]
Answer D AnswerD::Gamma cells
Answer D Explanation [[AnswerDExp::Gamma cells, or PP cells, produce pancreatic polypeptide. Gamma cells form 3–5% of the total number of cells of the islets of langerhans.]]
Answer E AnswerE::Epsilon cells
Answer E Explanation [[AnswerEExp::Epsilon cells produce ghrelin. Epsilon cells form <1% of the total number of cells of the islets of langerhans.]]
Right Answer RightAnswer::B
Explanation [[Explanation::Hormones produced in the islets of Langerhans are secreted directly into the blood flow by (at least) five types of cells. In rat islets, endocrine cell subsets are distributed as follows:

Since insulin is produced in the beta cells, the insulin antibodies will label the beta cells in red.
Educational Objective: The islets of langerhans are formed by different types of cells. Beta cells occupy the center of the islet of langerhans and produce insulin.
References: Gomori, George. "Observations with differential stains on human islets of Langerhans." The American journal of pathology 17.3 (1941): 395.
First Aid 2015 page 313]]

Approved Approved::Yes
Keyword WBRKeyword::Beta cells, WBRKeyword::Insulin, WBRKeyword::Diabetes, WBRKeyword::Histology
Linked Question Linked::
Order in Linked Questions LinkedOrder::