NEET-PG 2015 Practice Questions

Q: Which carpal bone does not articulate with the radius?

Pisiform. ***Pisiform*** - The **pisiform** is a sesamoid bone located within the tendon of the **flexor carpi ulnaris** muscle. - It articulates only with the **triquetrum**, not directly with the radius. *Scaphoid* - The **scaphoid** is one of the carpal bones that directly articulates with the radius, forming part of the **radiocarpal joint**. - It is located in the **proximal row** of carpal bones on the lateral side. *Lunate* - The **lunate** is another bone in the proximal carpal row that articulates directly with the **radius**, alongside the scaphoid. - It plays a crucial role in wrist movement and stability. *Triquetrum* - The **triquetrum** is a carpal bone in the proximal row, located medially. - Although it is in the proximal row, it primarily articulates with the **ulnar articular disc** (triangular fibrocartilage complex), which separates it from the distal ulna, and does not directly articulate with the radius.

Q: Posterior cardinal veins develop into:

Common iliac vein. ***Common iliac vein*** - The **posterior cardinal veins** are paired primitive veins in the embryo that drain the caudal body. - The **caudal portions** of the posterior cardinal veins persist and directly form the **common iliac veins** and contribute to the internal iliac veins [1]. - This is the **primary and most direct derivative** of the posterior cardinal veins, making it the best answer. *Azygos vein* - The **azygos vein** develops from the **right supracardinal vein** + **cranial portion of the right posterior cardinal vein**. - While posterior cardinal veins do contribute to its formation, this is not the primary derivative. - The middle portions of posterior cardinal veins regress, and the supracardinal contribution is more significant. *Hemiazygos vein* - The **hemiazygos vein** is derived from the **left supracardinal vein** + **cranial portion of the left posterior cardinal vein**. - Similar to the azygos, posterior cardinal veins contribute but are not the primary source. - The supracardinal vein provides the major contribution. *Parts of inferior vena cava* - The **IVC** forms from multiple embryonic veins: right vitelline vein (hepatic segment), right subcardinal vein (renal segment), right supracardinal vein (infrarenal segment), and hepatic veins. - While the common iliac veins (derived from posterior cardinal veins) drain into the IVC, the posterior cardinal veins themselves do **not directly form the IVC proper**. - The posterior cardinal veins largely regress in their middle portions.

Q: Which blinding technique is considered the most effective in clinical trials?

Double blinding. **Double blinding** - Involves both the **participants** and the **researchers/investigators** being unaware of the treatment assignment. - This method effectively minimizes bias from both **subject expectation** (placebo effect) and **observer expectation** (detection bias). *Single blinding* - Only the **participant** is unaware of the treatment they are receiving, while the investigator knows. - While it reduces participant bias, it can still introduce bias from the investigator regarding **outcome assessment** or **patient interaction**. *Triple blinding* - Extends blinding to include the **data analyst** who is also unaware of the treatment assignments during analysis. - While theoretically offering an additional layer of protection against bias, its practical benefits over double blinding are often marginal and it's less commonly implemented due to **complexity**. *No blinding* - Both the **participants** and the **researchers** are aware of the treatment assignments (open-label study). - This approach is highly susceptible to **bias** from both participant and researcher expectations, significantly compromising the study's validity and reliability.

Q: Absence of the intrahepatic bile ducts leads to which syndrome?

Alagille Syndrome. ***Alagille Syndrome*** - Characterized by the **absence of intrahepatic bile ducts**, leading to cholestasis and liver dysfunction. - Often associated with **cardiac defects** and **skeletal abnormalities**, as well as distinct **facial features**. *Von Meyenburg Complexes* - Refers to **bile duct hamartomas**, which are developmental abnormalities but do not lead to complete absence of ducts. - Typically discovered incidentally and are not associated with syndromic presentations like Alagille syndrome. *Caroli Disease* - Involves **dilated intrahepatic bile ducts** [1] and does not result in their absence; thus, it leads to **recurrent cholangitis**. - More associated with **cysts** and can lead to biliary complications rather than complete duct loss. *Polycystic Liver Disease* - Characterized by the presence of multiple **cysts** in the liver, but the intrahepatic bile ducts are typically present. - It is often associated with **kidney cysts** and systemic manifestations, not the absence of bile ducts.

Q: Which of the following statements about Wilson's disease is true?

Low serum ceruloplasmin and high urinary copper. ***Low serum ceruloplasmin and high urinary copper*** - In **Wilson's disease**, there is a defect in **copper transport**, leading to impaired incorporation of copper into ceruloplasmin and reduced biliary excretion. - This results in **low serum ceruloplasmin** levels (since ceruloplasmin is the main copper-carrying protein in the blood) and **increased urinary copper excretion** as the body attempts to eliminate excess free copper. *Low serum ceruloplasmin and low urinary copper* - While **low serum ceruloplasmin** is characteristic, **low urinary copper** would indicate adequate copper elimination or a different condition, which is not the case for Wilson's disease. - Patients with Wilson's disease have **excess copper accumulation**, and increased urinary excretion is a compensatory mechanism [1]. *High serum ceruloplasmin and low urinary copper* - **High serum ceruloplasmin** is inconsistent with Wilson's disease, as ceruloplasmin levels are typically low due to the impaired copper binding. - **Low urinary copper** excretion would indicate normal or low total body copper, which contradicts the copper overload seen in Wilson's disease. *High serum ceruloplasmin and high urinary copper* - **High serum ceruloplasmin** would suggest normal or increased ceruloplasmin synthesis or release, which is contrary to the pathophysiology of Wilson's disease. - Although **high urinary copper** is a feature, it isn't accompanied by high ceruloplasmin in this condition, as ceruloplasmin is primarily involved in carrying copper in the blood rather than excreting excess copper [1].

Q: Cataract is caused by all except:

MRI. ***MRI*** - Magnetic Resonance Imaging (MRI) uses powerful **magnetic fields** and radio waves to generate images, which are not known to cause cataracts. - The energy used in MRI is **non-ionizing** and does not directly damage lens proteins. *Ultraviolet radiation* - Prolonged exposure to **UV-B radiation** is a significant risk factor for the development of various types of cataracts, especially cortical and posterior subcapsular cataracts. - UV radiation can cause oxidative damage to lens proteins and lipids, leading to their aggregation and opacification. *Infrared radiation* - Chronic exposure to high levels of **infrared (IR) radiation**, such as that experienced by glassblowers or steelworkers, can lead to "glassblower's cataract" or "heat cataract." - IR radiation causes thermal damage to the lens, particularly the anterior capsule and subcapsular region. *Microwave radiation* - High-intensity **microwave radiation** has been implicated in the formation of cataracts, particularly in occupational exposure scenarios. - It causes thermal effects within the lens due to absorption of energy, leading to protein denaturation and opacification.

Q: Newborns typically lose how much weight in the first week?

5-10%. ***5-10%*** - **Physiologic weight loss** of 5-10% of birth weight is normal in newborns during the first week of life. - This loss is primarily due to the **mobilization of extracellular fluid** and delayed onset of full milk production (lactogenesis). - Most infants regain their birth weight by **10-14 days** of age. *1-2%* - A weight loss of only 1-2% in the first week would be **less than expected** and might suggest the infant is retaining excess fluid. - While not necessarily pathological, it's at the **lower end of the normal range** and less typical than the 5-10% range. *11-15%* - A weight loss greater than **10%** is generally considered **excessive** and indicates inadequate feeding or possible dehydration. - Weight loss of 11-15% typically requires **closer monitoring**, feeding assessment, and possible lactation support or supplementation. *15-20%* - A weight loss of 15-20% is significantly **above the normal physiological range** and represents a serious concern for **severe dehydration** or inadequate nutritional intake. - This degree of weight loss would warrant **immediate medical evaluation** and intervention, including possible hospitalization.

Q: Drug not used in pulmonary hypertension is:

Alpha blocker. ***Alpha blocker*** - Alpha-blockers primarily cause **systemic vasodilation** [1] and are not indicated for the specific pulmonary vascular remodeling and vasoconstriction seen in pulmonary hypertension. [2] - Their use could lead to an undesirable drop in **systemic blood pressure** [3] without adequately addressing the pulmonary arterial pressure. *Calcium channel blocker* - **Calcium channel blockers** (namely **dihydropyridines** like nifedipine and amlodipine) are used in a small subset of pulmonary hypertension patients who are **vasoreactive** on acute testing. - They work by relaxing pulmonary arterial smooth muscle, reducing **pulmonary vascular resistance**. *Endothelin receptor antagonist* - **Endothelin receptor antagonists** (e.g., bosentan, ambrisentan) block the effects of **endothelin-1**, a potent vasoconstrictor and smooth muscle proliferator involved in pulmonary hypertension. - They improve hemodynamics, exercise capacity, and clinical outcomes by preventing **vasoconstriction** and **vascular remodeling**. *Prostacyclin* - **Prostacyclin analogs** (e.g., epoprostenol, treprostinil) are potent **vasodilators** and inhibitors of platelet aggregation. - They are highly effective in treating severe pulmonary hypertension by relaxing pulmonary arteries and preventing **thrombosis**.

Q: What is the cause of cough and angioedema in a patient receiving ACE inhibitors?

Bradykinin accumulation. ***Bradykinin accumulation*** - **ACE inhibitors** block the enzyme **angiotensin-converting enzyme (ACE)**, which is responsible for degrading **bradykinin**. - The resulting **accumulation of bradykinin** is a potent vasodilator and increases capillary permeability, leading to **cough** (5-20% of patients) and **angioedema** (0.1-0.7%). - This is the most **precise answer** as it specifies the mechanism: impaired degradation leading to accumulation. *Bradykinin (alone)* - While **bradykinin** is the mediator involved, this option is **less precise** than "bradykinin accumulation." - **Bradykinin** is naturally present in the body; the problem with ACE inhibitors is specifically the **accumulation** due to impaired degradation. - The correct answer requires understanding that it's the **excess levels**, not just the presence, that causes symptoms. *Increased renin levels* - **ACE inhibitors** block the conversion of **angiotensin I to angiotensin II**, leading to reduced negative feedback. - This causes **compensatory increase in renin secretion** from the juxtaglomerular apparatus. - However, increased renin is **not responsible** for cough or angioedema—these are bradykinin-mediated effects. *Increased angiotensin-II levels* - **ACE inhibitors** actually **decrease angiotensin-II levels**, which is their primary **antihypertensive mechanism**. - This option is **incorrect** as ACE inhibitors reduce (not increase) angiotensin-II. - The reduction in angiotensin-II does not cause cough or angioedema.

Q: What is the mechanism of action of ticagrelor?

P2Y12 receptor antagonist. ***P2Y12 receptor antagonist*** - **Ticagrelor** is an **oral antiplatelet drug** that reversibly binds to the **P2Y12 ADP receptor** on platelet surfaces. - By blocking this receptor, it prevents **ADP-mediated platelet activation** and subsequent aggregation, reducing the risk of thrombotic events. *Cox inhibition* - **COX inhibitors** like **aspirin** prevent the synthesis of **thromboxane A2**, a powerful platelet aggregator. - This mechanism is characteristic of **NSAIDs** and **aspirin**, not ticagrelor. *GPIIB/IIIA inhibition* - **GPIIb/IIIa inhibitors** (e.g., abciximab, eptifibatide, tirofiban) directly block the final common pathway for platelet aggregation by preventing **fibrinogen binding** to the GPIIb/IIIa receptor. - While also an antiplatelet mechanism, this is distinct from ticagrelor's action on the P2Y12 receptor. *Inhibition of thromboxane synthase* - Inhibition of **thromboxane synthase** would reduce the production of **thromboxane A2**, similar to the effect of COX inhibition. - This is not the primary mechanism of action for ticagrelor; drugs like **dazoxiben** or **picotamide** act through this pathway.

Question 1

Which carpal bone does not articulate with the radius?

Accepted Answer

Pisiform

Answer

Scaphoid

Answer

Lunate

Answer

Triquetrum

Question 2

Posterior cardinal veins develop into:

Accepted Answer

Common iliac vein

Answer

Parts of inferior vena cava

Answer

Hemiazygos vein

Answer

Azygos vein

Question 3

Which blinding technique is considered the most effective in clinical trials?

Accepted Answer

Double blinding

Answer

Triple blinding

Answer

No blinding

Answer

Single blinding

Question 4

Absence of the intrahepatic bile ducts leads to which syndrome?

Accepted Answer

Alagille Syndrome

Answer

Polycystic Liver Disease

Answer

Caroli Disease

Answer

Von Meyenburg Complexes

Question 5

Which of the following statements about Wilson's disease is true?

Accepted Answer

Low serum ceruloplasmin and high urinary copper

Answer

Low serum ceruloplasmin and low urinary copper

Answer

High serum ceruloplasmin and low urinary copper

Answer

High serum ceruloplasmin and high urinary copper

Question 6

Cataract is caused by all except:

Accepted Answer

MRI

Answer

Ultraviolet radiation

Answer

Infrared radiation

Answer

Microwave radiation

Question 7

Newborns typically lose how much weight in the first week?

Accepted Answer

5-10%

Answer

1-2%

Answer

11-15%

Answer

15-20%

Question 8

Drug not used in pulmonary hypertension is:

Accepted Answer

Alpha blocker

Answer

Endothelin receptor antagonist

Answer

Prostacyclin

Answer

Calcium channel blocker

Question 9

What is the cause of cough and angioedema in a patient receiving ACE inhibitors?

Accepted Answer

Bradykinin accumulation

Answer

Bradykinin

Answer

Increased renin levels

Answer

Increased angiotensin-II levels

Question 10

What is the mechanism of action of ticagrelor?

Accepted Answer

P2Y12 receptor antagonist

Answer

Cox inhibition

Answer

Inhibition of thromboxane synthase

Answer

GPIIb/IIIa inhibition

NEET-PG 2015

Anatomy

Community Medicine

Internal Medicine

Ophthalmology

Pediatrics

Pharmacology