NEET-PG 2015 Practice Questions

Q: When does the rudimentary cochlea develop in the fetus?

4th to 8th week. 4th to 8th week - The **cochlea** begins its development from the **otic vesicle** around the **4th week** of gestation and undergoes extensive coiling. - By the **8th week**, the cochlea has achieved its characteristic snail-like shape, though further differentiation and maturation continue. *First week* - The first week of embryonic development involves **fertilization**, **cleavage**, and **implantation**, with no organogenesis occurring [1]. - At this stage, the embryo is a **blastocyst**, and specific organ structures like the cochlea have not yet begun to form [1]. *8th to 12th week* - While significant maturation of the inner ear structures occurs during this period, the **rudimentary cochlea** has already formed its basic shape by the 8th week. - This phase involves further differentiation of the **organ of Corti** and development of neural connections, rather than the initial formation of the cochlea itself. *16 to 20th week* - By the 16th to 20th week, the inner ear structures are largely developed and functional, including the **cochlea**, which is capable of responding to sound stimuli. - This period marks the onset of **fetal hearing** and continued fine-tuning of the auditory system, far beyond the rudimentary stage of cochlear development.

Q: Which of the following is not a feature of ethmoidal polyp?

Commonly found as a single polyp. ***Commonly found as a single polyp*** - **Ethmoidal polyps** are typically **multiple** and bilateral, originating from the ethmoid sinuses. - They rarely present as a single, isolated polyp, which is more characteristic of antrochoanal polyps. - This is the key distinguishing feature that makes this statement INCORRECT. *Common in adults* - **Ethmoidal polyps** are indeed **more prevalent in adults** than in children. - Peak incidence occurs between 30-50 years of age. - Their incidence tends to increase with age, often associated with chronic rhinosinusitis. *Commonly bilateral* - **Ethmoidal polyps** almost invariably present as **bilateral polyps**, involving both sides of the nasal cavity. - This bilateral nature is a key differentiating feature from antrochoanal polyps, which are typically unilateral. - Bilateral presentation is one of the hallmark characteristics of ethmoidal polyps. *Associated with chronic rhinosinusitis* - **Ethmoidal polyps** are strongly associated with **chronic rhinosinusitis with nasal polyposis (CRSwNP)**. - They arise from chronic mucosal inflammation of the ethmoid sinuses. - Often associated with conditions like aspirin-exacerbated respiratory disease (AERD/Samter's triad) and non-allergic eosinophilic inflammation.

Q: Which of the following is NOT a common cause of acute renal failure?

Chronic kidney disease due to analgesic nephropathy. Chronic kidney disease due to analgesic nephropathy - This is a cause of chronic kidney disease, characterized by gradual, irreversible kidney damage over a long period due to prolonged use of certain analgesics. [1] - It does not present as an acute, sudden decline in kidney function, which is the hallmark of acute renal failure. [1] Acute pyelonephritis - Severe cases of acute pyelonephritis (kidney infection) can lead to acute kidney injury due to sepsis, inflammation, and potential obstruction. [1] - The systemic inflammatory response and direct tissue damage can impair kidney function rapidly. [1] Acute kidney injury from snakebite - Snake envenomation can cause acute kidney injury through various mechanisms, including hemolysis, rhabdomyolysis, direct nephrotoxicity, and systemic hypotension. - These effects can lead to rapid and severe kidney damage. Acute kidney injury due to rhabdomyolysis - Rhabdomyolysis involves the breakdown of skeletal muscle tissue, releasing large amounts of myoglobin into the bloodstream. [1] - Myoglobin is toxic to the renal tubules, leading to acute tubular necrosis and rapid onset of acute kidney injury. [1]

Q: Murmur heard in aortic stenosis

Right 2nd intercostal, high pitch systolic ejection murmur. ***Right 2nd intercostal, high pitch systolic ejection murmur*** - The murmur of **aortic stenosis** is classically heard loudest at the **right second intercostal space** (aortic area) due to turbulent flow through the stenosed aortic valve. - It is a **high-pitched, systolic ejection murmur** with a crescendo-decrescendo pattern, often radiating to the carotid arteries [2]. *Apex, low pitch murmur associated with mitral valve issues* - A murmur heard at the **apex** that is low-pitched typically suggests **mitral stenosis**, which is a diastolic rumble, not an aortic stenosis murmur [1]. - This option refers to characteristics associated with **mitral valve disease**, not aortic stenosis. *Pan-systolic murmur, high pitch murmur associated with mitral regurgitation* - A **pan-systolic murmur** is characteristic of conditions like **mitral regurgitation** or tricuspid regurgitation, where blood flows throughout the entire systole [3]. - While it can be high-pitched, its pan-systolic nature and association with mitral regurgitation make it distinct from aortic stenosis. *Left Sternal area, murmur indicating mitral regurgitation* - Murmurs heard primarily at the **left sternal area** can indicate various conditions, but this option specifically points to **mitral regurgitation**. - **Mitral regurgitation** is better heard at the apex and usually radiates to the axilla, and the description does not fit the typical presentation of aortic stenosis [3].

Q: What is a potential outcome of the integration of a viral genome into a host cell chromosome?

All of the options. ***All of the options*** - The insertion of a viral genome, known as a **provirus**, into the host chromosome can lead to a variety of sustained and complex interactions. - This integration can cause **long-term changes** in cell behavior, including altered gene expression and cell cycle regulation, which may manifest as any of the specified outcomes. *Malignancy* - Viral integration can interrupt or activate host genes, such as **oncogenes** or **tumor suppressor genes**, leading to uncontrolled cell proliferation and potential tumor formation. - An example is **human papillomavirus (HPV)** integrating into host cells, increasing the risk of cervical cancer. *Altered growth* - Integration can change the cell's normal growth patterns, either by promoting excessive division or by causing cell cycle arrest, impacting tissue development and function. - This can be due to the insertion of viral promoters or enhancers near growth-regulating genes. *Latency* - The integrated viral genome can remain dormant within the host chromosome without producing new viral particles for extended periods, a state known as **latency**. - During latency, the virus can be reactivated later to cause a productive infection, as seen with **herpesviruses**.

Q: River blindness is caused by?

Onchocerca volvulus. ***Onchocerca volvulus*** - **River blindness**, or **onchocerciasis**, is caused by the parasitic nematode *Onchocerca volvulus*. - This parasite is transmitted by the bite of infected **blackflies** (genus *Simulium*), which breed in fast-flowing rivers. *Loa loa* - *Loa loa* causes **Loiasis**, also known as African eye worm disease. - While it can manifest as an eye worm and cause itching and swelling, it does not typically lead to permanent blindness or the widespread skin lesions associated with river blindness. *Ascaris* - *Ascaris lumbricoides* causes **ascariasis**, an intestinal infection. - Symptoms are primarily gastrointestinal, such as abdominal pain, malnutrition, and, in severe cases, intestinal obstruction; it does not affect the eyes or cause blindness. *B. malayi* - *Brugia malayi* is one of the causes of **lymphatic filariasis**, also known as **elephantiasis**. - This disease primarily affects the lymphatic system, causing severe swelling in the limbs and genitals, but it does not cause blindness.

Q: All are true regarding cornea except:

The cornea is richly vascular.. ***The cornea is richly vascular.*** - The cornea is an **avascular** tissue, meaning it lacks blood vessels, which is crucial for its transparency. - This avascularity helps prevent light scatter and maintains clear vision. - The cornea receives nutrition from the **aqueous humor**, **tear film**, and **limbal blood vessels** through diffusion. *Endothelium help in maintaining dehydrated state* - The **corneal endothelium** actively pumps fluid out of the corneal stroma via **Na-K-ATPase pumps**, preventing swelling and maintaining its relative state of dehydration. - This **deturgescence** is essential for the cornea's transparency and optimal refractive power. *Oxygen is mostly derived by epithelium directly from the air through tear film* - The corneal **epithelium** primarily obtains oxygen directly from the atmosphere via the **tear film** when the eyes are open. - During sleep, oxygen is primarily supplied by the **palpebral conjunctival vessels**. *Corneal thickness is greater at periphery than center* - The cornea is **thinner at the center** (around 520-540 µm) and gradually **thicker towards the periphery** (around 600-640 µm). - This structural difference contributes to its optical properties and mechanical stability.

Q: Rosette cataract is seen due to:

Trauma. ***Trauma*** - A **rosette cataract** is a classic sign of **blunt or penetrating ocular trauma**, where the force disrupts the lens fibers, leading to a characteristic star-shaped opacity. - The trauma causes a rapid swelling and opacification of the lens, often in the anterior or posterior subcapsular regions in a flower-petal or stellar pattern. *Copper foreign body* - A **copper foreign body** typically causes a **chalcosis lentis**, characterized by a **sunflower cataract** (deposits in the anterior capsule) due to copper deposition. - This is distinct from a rosette cataract, which forms due to the mechanical disruption of lens integrity rather than elemental deposition. *Diabetes* - **Diabetic cataracts** are typically either **"snowflake" cataracts** (rapidly progressive in younger patients with uncontrolled diabetes) or more commonly **age-related cataracts** that progress faster in diabetic patients. - These are metabolically induced cataracts, not presenting with the characteristic rosette or star-shaped pattern associated with trauma. *Hyperparathyroidism* - **Hyperparathyroidism** can lead to **metabolic cataracts** due to chronic hypercalcemia, which can cause calcium deposition within the lens. - These cataracts are typically described as **punctate cortical or subcapsular opacities**, rather than the distinct rosette shape seen after trauma.

Q: What is the primary predisposing factor for retinopathy of prematurity?

Low gestational age. ***Low gestational age*** - **Prematurity** is the most significant risk factor, as the **retinal vasculature** is still immature and susceptible to abnormal development. - The earlier the gestational age, the **higher the risk** of ROP developing and progressing to severe stages. *Low birth weight* - While strongly correlated with ROP, **low birth weight** is often a consequence of prematurity rather than the primary predisposing factor itself. - Many term infants can have low birth weight due to **intrauterine growth restriction** but do not typically develop ROP. *Oxygen toxicity* - **Supplemental oxygen** can exacerbate ROP by causing initial **vasoconstriction** and subsequent abnormal vessel proliferation. - However, it acts as a secondary trigger in an already vulnerable, premature retina, not the primary predisposing factor. *Carbohydrate excess* - **Carbohydrate excess** is not a recognized predisposing factor for retinopathy of prematurity. - This condition is primarily related to the **vascular development of the retina** in premature infants.

Q: In a case of myopia, LASIK can correct up to how many diopters?

-12D. ***-12D*** - LASIK can effectively correct myopia up to approximately **-12 diopters** in suitable candidates, though this can vary slightly based on individual corneal thickness and health. - The excimer laser reshapes the **cornea** to reduce its curvature, thereby decreasing the focusing power of the eye and correcting the myopic error. *-20D* - While some highly myopic individuals might desire such a correction, LASIK is generally not recommended or effective for myopia higher than **-12 to -14 diopters** due to limitations in corneal tissue removal and potential for complications. - Correcting very high myopia with LASIK would require removing too much corneal tissue, potentially leading to **corneal instability** or vision-threatening complications like **ectasia**. *-6D* - This is a common and highly successful range for LASIK correction, but it represents only a **moderate level of myopia** and not the maximum correctable range. - Patients with myopia of -6D typically achieve excellent visual outcomes with very low complication rates after LASIK. *-4D* - This is a relatively low level of myopia, and LASIK is very effective for this amount of correction, but it is far from the **upper limit** of what LASIK can achieve. - This level of correction requires minimal corneal reshaping and typically results in a very high success rate and predictable outcomes.

Question 1

When does the rudimentary cochlea develop in the fetus?

Accepted Answer

4th to 8th week

Answer

First week

Answer

8th to 12th week

Answer

16 to 20th week

Question 2

Which of the following is not a feature of ethmoidal polyp?

Accepted Answer

Commonly found as a single polyp

Answer

Common in adults

Answer

Commonly bilateral

Answer

Associated with chronic rhinosinusitis

Question 3

Which of the following is NOT a common cause of acute renal failure?

Accepted Answer

Chronic kidney disease due to analgesic nephropathy

Answer

Acute pyelonephritis

Answer

Acute kidney injury from snakebite

Answer

Acute kidney injury due to rhabdomyolysis

Question 4

Murmur heard in aortic stenosis

Accepted Answer

Right 2nd intercostal, high pitch systolic ejection murmur

Answer

Apex, low pitch murmur associated with mitral valve issues

Answer

Pan-systolic murmur, high pitch murmur associated with mitral regurgitation

Answer

Left Sternal area, murmur indicating mitral regurgitation

Question 5

What is a potential outcome of the integration of a viral genome into a host cell chromosome?

Accepted Answer

All of the options

Answer

Altered growth

Answer

Malignancy

Answer

Latency

Question 6

River blindness is caused by?

Accepted Answer

Onchocerca volvulus

Answer

Loa loa

Answer

Ascaris

Answer

B. malayi

Question 7

All are true regarding cornea except:

Accepted Answer

The cornea is richly vascular.

Answer

Endothelium help in maintaining dehydrated state

Answer

Oxygen is mostly derived by epithelium directly from the air through tear film

Answer

Corneal thickness is greater at periphery than center

Question 8

Rosette cataract is seen due to:

Accepted Answer

Trauma

Answer

Hyperparathyroidism

Answer

Copper foreign body

Answer

Diabetes

Question 9

What is the primary predisposing factor for retinopathy of prematurity?

Accepted Answer

Low gestational age

Answer

Oxygen toxicity

Answer

Carbohydrate excess

Answer

Low birth weight

Question 10

In a case of myopia, LASIK can correct up to how many diopters?

Accepted Answer

-12D

Answer

-4D

Answer

-20D

Answer

-6D

NEET-PG 2015

Anatomy

ENT

Internal Medicine

Microbiology

Ophthalmology