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Free STEP1 Exam Braindumps (page: 33)

Page 33 of 213
PDF with 845 Questions

A patient suffering from Charcot-Marie-Tooth disease displays progressive degeneration of peripheral nerves, distal muscle weakness and atrophy, and defects in deep tendon reflexes. This condition is associated with an abnormal mutation in the gene encoding connexin-32. Connexins are normally found in which type of cell junctions?

  1. communicating (gap) junction
  2. hemidesmosome
  3. macula adherens (spot desmosome)
  4. occluding (tight) junction
  5. zonula adherens (belt desmosome)

Answer(s): A

Explanation:

Communicating (gap) junctions are formed by connexins, which associate together in groups of six to form connexons. The alignment of connexions between two cells allows for direct channels of communication between their cytoplasms, facilitating the transfer of molecules such as calcium or cyclic adenosine monophosphate (cAMP). Hemidesmosome (choice B), macula adherens (spot desmosome; choice C), and zonula adherens (belt desmosome; choice E) are classified as anchoring junctions. They are associated with intermediate filaments (hemidesmosome and macula adherens) or with actin microfilaments (zonula adherens), but not connexins. Occluding (tight) junctions (choice D) contain the proteins occludin and claudin but not connexin.



Calcitonin decreases blood calcium and boneresorbing activity in which of the following?

  1. osteoblast
  2. osteoclast
  3. osteocyte
  4. osteon
  5. osteoprogenitor cells

Answer(s): B

Explanation:

Calcitonin reduces the surface ruffling of osteoclasts and their activity. Osteoclasts are formed by fusion of blood monocyte derivatives and are components of the mononuclear phagocyte system. Under the influence of parathyroid hormone, osteoclasts enlarge their ruffled borders and increase their bone- resorbing activity. Osteoprogenitor cells (choice E), osteoblast (choice A), and osteocyte (choice C) are bone-forming cells. Osteon (choice D) is another name for the haversian system which is the haversian canal, its contents, surrounding lamellae, and osteocytes.



During development, which of the following structures act as a temporary set of kidneys in the fetus?

  1. mesonephroi
  2. metanephroi
  3. paramesonephric ducts
  4. pronephroi
  5. ureteric bud

Answer(s): A

Explanation:

The second set or mesonephroi appear late in the fourth week and are functional until the permanent kidneys or metanephroi are fully developed. During development, three sets of kidneys are formed in the embryo. The first set or pronephroi (choice D) are transitional, nonfunctional structures that appear around the fourth week of development. Next come the mesonephroi, then the permanent set of kidneys develops from the metanephroi. The paramesonephric ducts (choice C) are structures developing lateral to the gonads and mesonephric ducts. They play an essential role in the female reproductive system, but are not involved in the formation of the kidneys. The ureteric bud (choice E) is an outgrowth from the mesonephric duct that gives rise to the ureter, renal pelvis, calices, and collecting tubules.



In adults, lack of vitamin D gives rise to the disease osteomalacia characterized by progressive softening and bending of the bones. This is due to a defect in the mineralization of the osteoid. Under normal conditions, the osteoid is found along which of the following locations?

  1. the interface between osteocytes and bones
  2. the interface between osteoprogenitor cells and bone marrow
  3. the interface between the fibroblasts in the periosteum
  4. the interface between the osteoblast and bone
  5. the ruffled border of osteoclasts

Answer(s): D

Explanation:

Osteoid is the unmineralized organic matrix formed by osteoblasts and found at the interface between these cells and bone. Osteocytes (choice A) are surrounded by bone and no longer manufacture osteoid.
Osteoprogenitor cells (choice B) are similar to stem cells and do not manufacture bone material.
Fibroblasts (choice C) are cells of connective tissue forming the periosteum and not bone. Osteoclasts (choice E) are bone-resorbing cells.



Page 33 of 213



Post your Comments and Discuss USMLE STEP1 exam with other Community members:

Karlik commented on September 27, 2024
I passed the exam with help from this questions :)
Anonymous
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Nate commented on September 27, 2024
Has anyone recently taken the exam? Can anyone confirm these questions are similar or word for word?
Anonymous
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Birkha commented on September 27, 2024
NO comments
BHUTAN
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raba commented on September 26, 2024
@khorshal can i use this alone to pass the exams
Anonymous
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raba commented on September 26, 2024
some of the questions are straight forward
Anonymous
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Judwa commented on September 26, 2024
This exam is super hard. I was overwhelmed. After using this exam dump, I went into the exam feeling a bit better. I passed my test. :-)
INDIA
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Jubran commented on September 26, 2024
Clear explanations and well-structured content made it so much easier to prepare and pass.
UNITED STATES
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KXK commented on September 26, 2024
The study guide was concise yet comprehensive. It helped me focus on the key topics and feel more prepared than ever!
INDIA
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Chandra commented on September 26, 2024
I passed my exam with ease, thanks to the targeted material in this guide. It made a huge difference in how I prepared.
CANADA
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raba commented on September 26, 2024
I was thinking question 16 should be a legacy systems
Anonymous
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Bubba commented on September 26, 2024
Good work guys. The layout is user-friendly, and the content is spot on.
Hong Kong
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rabihu commented on September 26, 2024
These are really challenging questions.i love it
Anonymous
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Murad commented on September 26, 2024
This guide gave me the exact focus I needed to pass my exam on the first try. Highly effective and reliable.
Turkey
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raba commented on September 26, 2024
these are really good questions
Anonymous
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Kg commented on September 26, 2024
hi @phil , thank you for the response , basically i must just check wether the answers are correct
Anonymous
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Alhassan commented on September 26, 2024
these are really good questions
Anonymous
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Jose commented on September 26, 2024
these are really good questions
Anonymous
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David commented on September 26, 2024
good Questions
Anonymous
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Mohammed commented on September 26, 2024
Absolutely grateful for this exam dumps. Passed on the first set down.
France
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Phil commented on September 26, 2024
Hi @kg I feel you. Based on my experience, the questions are valid but some of the answers were not accurate. So I managed to study and kinda figure these answers. For me the accuracy of the questions were more important and I saw most of them in the exam.
Anonymous
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Madhan commented on September 26, 2024
Useful questions
INDIA
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Owol Sentmi commented on September 26, 2024
great Questions
Anonymous
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Noha commented on September 26, 2024
Feeling very confident now. Went over the free questions here then decided to buy the full PDF and test engine with the sale price and now ready to write my test. Will share my experience next week after I go for my exam. Wish me luck guys.
UNITED STATES
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Baylis commented on September 26, 2024
I am certified now. Thank you team.
UNITED STATES
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Harper commented on September 26, 2024
If you have access to full version of this exam dumps then you are good to go and pass your exam.
EUROPEAN UNION
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Suil commented on September 26, 2024
Very good Practice questions
CHINA
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lala commented on September 26, 2024
really helping
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Champ commented on September 26, 2024
Good to see that something is still free. I truly appreciate this service.
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kg commented on September 26, 2024
anyone who sees this comment please respond to my question, can the answers on freedumps be trusted , because im using different materials also from exam topics and the answers dont look the same
Anonymous
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Shams commented on September 25, 2024
This exam is valid in UAE. I passed.
UNITED ARAB EMIRATES
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rb commented on September 25, 2024
these are really good questions
Anonymous
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Muhammad Saleem commented on September 25, 2024
In which Service Studio layer can Entities be found? I think Answer should be Data but It's Interface
UNITED ARAB EMIRATES
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Khoshal commented on September 25, 2024
@Emily I have taken this exam and yes it is hard. But I managed to pass this exam with some study and using the questions from this exam dumps. I would say about 80% more or less of these questions are in the exam.
INDIA
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Emily commented on September 25, 2024
I understand that most users reported that this exam is very hard. But how much of these questions were present in the exam if anyone has taken the exam? Please share.
Hong Kong
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