NEET-PG 2015 Practice Questions

Q: Sertoli cells are derived from -

Coelomic epithelium. Sertoli cells are derived from the **coelomic epithelium** (surface epithelium) of the urogenital ridge during gonadal development. - The coelomic epithelium proliferates to form the **primitive sex cords** (medullary cords in males), and cells within these cords differentiate into Sertoli cells. - These cells are essential for **spermatogenesis**, providing structural support and nutrition to developing germ cells, and producing **anti-Müllerian hormone (AMH)** which causes regression of Müllerian ducts in male development [1]. *Germinal epithelium* - This is an **outdated term** previously used for the surface epithelium of the gonad, based on the misconception that it gave rise to germ cells. - Modern embryology uses the term **coelomic epithelium** or surface epithelium instead. - While historically used, this terminology is no longer preferred in current medical literature. *Genital swelling* - **Genital swellings** (labioscrotal swellings) are external mesodermal structures that develop into the **scrotum** in males or **labia majora** in females. - These are external genitalia components and are not the source of internal testicular cells like Sertoli cells. *Primordial germ cells* - **Primordial germ cells (PGCs)** originate from the epiblast, migrate via the hindgut to the developing gonads, and differentiate into **spermatogonia** (males) or **oogonia** (females) [1]. - They form the **germ cell lineage** (gametes), not somatic support cells like Sertoli cells, which are of coelomic epithelial origin.

Q: Which subtype of Acute Myeloid Leukemia (AML) is associated with the best prognosis?

Acute promyeloblastic leukemia (M3). ***Acute promyeloblastic leukemia (M.3)*** [1] - **Best prognosis** in acute myeloid leukemia (AML) is associated with acute promyeloblastic leukemia due to its responsiveness to **all-trans retinoic acid (ATRA)** treatment. [1] - This type often presents with a **prominent coagulopathy**, but successful treatment can lead to **long-term remission**. *Acute monocytic leukemia* - Generally associated with **poor prognosis** and is characterized by a high white blood cell count and organ infiltration. - It lacks the favorable features seen in acute promyeloblastic leukemia, such as effective treatment outcomes. *Erythroleukemia* - Known for having a **poor prognosis** due to its aggressive nature and frequent association with complex chromosomal abnormalities. [1] - Treatment responses are often suboptimal compared to that of acute promyeloblastic leukemia. *Acute myelomonocytic leukemia* - Typically has an **intermediate prognosis** [1] and presents with a mixture of myeloid and monocytic features. - It does not have the same treatment responsiveness and favorable outcomes as seen in acute promyeloblastic leukemia.

Q: Most common lung cancer in non-smokers is:

Adenocarcinoma. ***Adenocarcinoma*** - **Adenocarcinoma** is the most common type of lung cancer found in non-smokers, often associated with peripheral lung nodules. - This subtype has a rising incidence rate, particularly among women and younger individuals, often linked to factors like **environmental exposures** or **genetics**. *None of the above* - This option is incorrect since adenocarcinoma is a recognized **primary lung cancer** type in non-smokers. - The statement does not address the specific cancer types and neglects to acknowledge the commonality of adenocarcinoma. *Squamous cell carcinoma* - Generally associated with smoking [1,2] and presents centrally in the lungs, making it less common among non-smokers. - Often linked to **cavitary lesions** [1] and associated with **hypercalcemia** due to parathyroid hormone-related peptide secretion. *Oat cell carcinoma* - Also known as small cell lung cancer (SCLC), is primarily linked to smoking and has a **very aggressive** nature. - Typically arises in the central airways and is associated with **paraneoplastic syndromes**, which are not relevant to the non-smoker context. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 336-337. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 720-721.

Q: Radiotherapy induced radiation pneumonitis is mediated by all of the following cytokines and factors except -

PAF. ***PAF*** - **Platelet-activating factor (PAF)** is primarily involved in **anaphylaxis**, **asthma**, and **allergic responses**, mediating inflammation through platelet aggregation and smooth muscle contraction. - While it has pro-inflammatory effects, it is **not a primary mediator** of the specific inflammatory cascade seen in radiotherapy-induced radiation pneumonitis. *TNF-α* - **Tumor Necrosis Factor-alpha (TNF-α)** is a crucial **pro-inflammatory cytokine** that plays a significant role in the initial acute phase of radiation pneumonitis. - It induces **cytotoxicity**, **apoptosis**, and the production of other inflammatory mediators, contributing to lung tissue damage. *TGF-β* - **Transforming Growth Factor-beta (TGF-β)** is a key cytokine involved in the **fibrotic phase** of radiation pneumonitis. - It promotes **fibroblast proliferation**, collagen synthesis, and extracellular matrix deposition, leading to lung scarring. *NF-kB* - **Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-kB)** is a master **transcription factor** that regulates the expression of numerous genes involved in inflammation and immune responses. - Radiation exposure **activates NF-kB**, leading to the transcription of various pro-inflammatory cytokines, including TNF-α, which contribute to radiation pneumonitis.

Q: Which of the following does not predispose to leukemia?

Alcohol. ***Alcohol*** - Alcohol consumption does not have a well-established association with an increased risk of leukemia compared to other factors. - While excessive alcohol can impact overall health, it is not considered a primary risk factor for developing leukemia. *Chemical exposure* - Certain chemicals, such as **benzene** and **formaldehyde**, are known to be **leukemogenic** and can increase the risk of leukemia. [1] - Occupational exposure to these chemicals has been linked to **acute myeloid leukemia (AML)** and other types of leukemia. [1] *Smoking* - Smoking has been clearly associated with an increased risk of **acute myeloid leukemia (AML)** and other hematologic malignancies. [1] - The toxins in tobacco smoke can cause **DNA damage**, contributing to the development of leukemia. *Genetic disorder* - Certain genetic disorders, like **Down syndrome** and **Fanconi anemia**, are associated with an increased risk of leukemia. - Individuals with these genetic predispositions have a higher likelihood of developing various forms of leukemia.

Q: Which of the following is NOT seen in polycythemia vera?

Increased erythropoietin. ***Increased erythropoietin*** - In polycythemia vera, patients usually exhibit **low erythropoietin levels** due to feedback inhibition from increased red blood cell mass. - The condition is driven by a **myeloproliferative disorder** [2], not by increased erythropoietin stimulation. *Most common cause of polycythemia* - This option is incorrect because polycythemia vera is specifically a type of **primary polycythemia** [1], rather than the most common cause, which is often **secondary causes** such as hypoxia or abnormal erythropoietin production. - Other causes including chronic lung disease or renal tumors are more prevalent sources of increased red blood cell production. *Intrinsic abnormality of hematopoietic precursors* - While polycythemia vera indeed involves an **abnormality in hematopoietic stem cells** [1], it is not the only mechanism leading to polycythemia; many cases have secondary causes. - Hence, this option misrepresents the specific and more accurate characterization of polycythemia vera. *Erythropoietin independent growth of red cell progenitors* - Polycythemia vera is associated with **erythropoietin-independent** proliferation of hematopoietic cells [2], which is characteristic of the condition due to mutations in **JAK2** [2,3]. - This accurately reflects a significant feature of the disease, aligning closely with the pathophysiology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 663-664. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 614-615. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of White Blood Cells, Lymph Nodes, Spleen, and Thymus, pp. 626-627.

Q: Which antigen is tested in routine Rh typing?

D antigen. ***D antigen*** - Routine Rh typing specifically tests for the **D antigen**, which determines the Rh status of an individual as Rh-positive or Rh-negative [1]. - The presence of the **D antigen** is crucial for blood transfusions and pregnancy management [1]. *A antigen* - The **A antigen** is tested in the context of the ABO blood group system, not specifically for Rh typing. - It does not provide information regarding the Rh factor which is critical in blood compatibility. *C antigen* - Similar to the **A antigen**, the **C antigen** is part of the broader Rh system but is not routinely assessed in standard Rh typing. - Its testing is typically reserved for specific clinical scenarios involving Rh incompatibility. *B antigen* - The **B antigen** pertains to the ABO blood group and does not relate to the Rh factor or routine Rh typing. - Rh typing is solely focused on the **presence of the D antigen** to determine the Rh status. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 627-628.

Q: Shelf life of platelets in a blood bank is

5 days. **5 days** - Platelets stored at **room temperature (20-24°C)** have a limited shelf life due to the risk of bacterial contamination and metabolic changes. - This short storage period ensures the **viability and function** of platelets for transfusion. *7 days* - A 7-day shelf life was initially proposed but was not widely adopted due to concerns about increased **bacterial growth** and the practical challenges of extended storage at room temperature. - The risk of **bacterial sepsis** significantly increases with longer room temperature storage. *10 days* - This duration is beyond the currently accepted shelf life for platelets, leading to an unacceptably high risk of **bacterial contamination** and reduced therapeutic efficacy. - Storing platelets for 10 days would likely result in an increased incidence of **transfusion-associated sepsis**. *21 days* - A shelf life of 21 days is typical for **red blood cells** when stored at 1-6°C with specific anticoagulants, but it is far too long for platelets. - Platelets stored for this duration at room temperature would be significantly **non-viable** and pose a severe risk of bacterial infection.

Q: Which of the following is an example of topical administration producing only local effects (not systemic)?

Topical corticosteroid cream. ***Topical corticosteroid cream*** - When applied to the skin for conditions like dermatitis, topical corticosteroids primarily exert their effects at the site of application, reducing **local inflammation** and itching. - While systemic absorption can occur with potent steroids over large areas, typical use aims for **localized action** without significant systemic effects. *Sublingual nitroglycerin* - This route is designed for **rapid systemic absorption** through the oral mucosa, bypassing first-pass metabolism to quickly treat angina. - The goal is a **widespread vasodilatory effect** throughout the body, not a local one within the mouth. *Transdermal patch* - Transdermal patches, such as those for nicotine or fentanyl, are specifically designed to deliver medication **systemically** through the skin into the bloodstream over a prolonged period. - They provide a **sustained release** and systemic therapeutic effect throughout the body. *Rectal diazepam* - Administered rectally, diazepam is absorbed into the systemic circulation to produce **CNS effects** such as sedation, anxiolysis, or anticonvulsant activity. - Although the administration is local, the intended clinical effect is **systemic** and widespread throughout the body.

Q: Fastest receptor mediated action is through?

Intrinsic ion channels. ***Intrinsic ion channels*** - Receptors that are also **ion channels** (ligand-gated ion channels) allow direct and rapid ion flow across the membrane upon ligand binding, leading to immediate changes in membrane potential. - This direct mechanism bypasses complex intracellular signaling cascades, resulting in the **fastest cellular response** compared to other receptor types. *Cell surface receptors* - This is a broad category that includes **G protein-coupled receptors** and **receptor tyrosine kinases**, which typically involve more complex and slower signaling pathways. - While located on the cell surface, not all receptors in this category mediate action as quickly as intrinsic ion channels. *Receptor tyrosine kinases* - These receptors initiate signaling by **phosphorylating tyrosine residues** on target proteins, triggering a cascade of intracellular events that take time to manifest. - Their action involves **multiple phosphorylation steps** and protein interactions, making their response slower compared to direct ion channels. *Intracellular receptors* - These receptors, such as **steroid hormone receptors**, are located in the cytoplasm or nucleus and require their ligands to diffuse across the cell membrane. - The activated receptor then typically translocates to the nucleus to regulate gene transcription, a process that is much **slower** due to gene expression and protein synthesis.

Question 1

Sertoli cells are derived from -

Accepted Answer

Coelomic epithelium

Answer

Genital swelling

Answer

Primordial germ cells

Answer

Germinal epithelium

Question 2

Which subtype of Acute Myeloid Leukemia (AML) is associated with the best prognosis?

Accepted Answer

Acute promyeloblastic leukemia (M3)

Answer

Acute myelo monocytic leukemia.

Answer

Acute monocytic leukemia.

Answer

Erythro leukemia

Question 3

Most common lung cancer in non-smokers is:

Accepted Answer

Adenocarcinoma

Answer

Squamous cell carcinoma

Answer

Oat cell carcinoma

Answer

Large cell carcinoma

Question 4

Radiotherapy induced radiation pneumonitis is mediated by all of the following cytokines and factors except -

Accepted Answer

PAF

Answer

NF-kB

Answer

TNF-α

Answer

TGF-β

Question 5

Which of the following does not predispose to leukemia?

Accepted Answer

Alcohol

Answer

Smoking

Answer

Chemical exposure

Answer

Genetic disorder

Question 6

Which of the following is NOT seen in polycythemia vera?

Accepted Answer

Increased erythropoietin

Answer

Intrinsic abnormality of hematopoietic precursors

Answer

Erythropoietin independent growth of red cell progenitors

Answer

Most common cause of primary polycythemia

Question 7

Which antigen is tested in routine Rh typing?

Accepted Answer

D antigen

Answer

C antigen

Answer

A antigen

Answer

B antigen

Question 8

Shelf life of platelets in a blood bank is

Accepted Answer

5 days

Answer

7 days

Answer

10 days

Answer

21 days

Question 9

Which of the following is an example of topical administration producing only local effects (not systemic)?

Accepted Answer

Topical corticosteroid cream

Answer

Sublingual nitroglycerin

Answer

Transdermal patch

Answer

Rectal diazepam

Question 10

Fastest receptor mediated action is through?

Accepted Answer

Intrinsic ion channels

Answer

Intracellular receptors

Answer

Cell surface receptors

Answer

Receptor tyrosine kinases

NEET-PG 2015

Anatomy

Internal Medicine

Pathology

Pharmacology