NEET-PG 2015 Practice Questions

Q: Which is the narrowest portion of the esophagus?

At the cricopharyngeal sphincter. ***At the cricopharyngeal sphincter*** - This is the **upper esophageal sphincter (UES)**, representing the **narrowest point of the entire esophagus** with a diameter of approximately **14 mm**. - It is formed by the **cricopharyngeus muscle**, which remains tonically contracted at rest to prevent air entry into the esophagus during respiration. - Located approximately **15 cm from the incisor teeth** at the level of the **C6 vertebra**. - **Clinical significance**: This is the most common site for impaction of foreign bodies and is a critical point during endoscopy. *At the crossing of the left main bronchus* - This represents the **middle constriction** where the esophagus is indented by the **left main bronchus** (approximately 22-23 cm from incisors). - This is a point of **extrinsic compression** rather than an intrinsic anatomical narrowing. - Diameter here is approximately **15.5 mm**, making it wider than the upper esophageal sphincter. - Foreign bodies and food boluses may lodge here, but it is not the narrowest point. *At the level of the aortic arch* - The **aortic arch** causes significant indentation and extrinsic compression, adjacent to the bronchial constriction. - This is also part of the **middle constriction** of the esophagus. - Despite this indentation, the lumen diameter is still greater than at the cricopharyngeal sphincter. *At the diaphragmatic aperture* - The esophagus passes through the **esophageal hiatus** at the level of **T10 vertebra** (approximately 40 cm from incisors). - This represents the **lower constriction** with a diameter of approximately **16-19 mm**. - While clinically important for hiatal hernias and lower esophageal sphincter pathology, it is the **widest of the three anatomical constrictions**.

Q: How often is the Sample Registration System conducted in India?

1 year. ***1 year*** - The **Sample Registration System (SRS)** in India is a large-scale demographic survey conducted **annually** to provide reliable estimates of birth rates, death rates, and other fertility and mortality indicators. - Its annual nature allows for regular monitoring of demographic changes and health trends across different states and regions. *6 months* - While some surveys or data collections might occur semi-annually, the comprehensive SRS is not conducted every six months. - Conducting a system as extensive as the SRS twice a year would be logistically challenging and resource-intensive. *2 years* - A biennial (every two years) frequency would mean less up-to-date data for tracking rapid demographic shifts or evaluating the immediate impact of health interventions. - The need for current statistics on vital events necessitates a more frequent survey than every two years. *5 years* - A quinquennial (every five years) frequency would provide very infrequent data, which is insufficient for effective public health planning and policy formulation. - Key demographic indicators are needed more regularly than every five years to respond to evolving health and population needs.

Q: Caldwell Luc Surgery has its approach to the maxillary antrum through ?

Gingivolabial sulcus. ***Gingivolabial sulcus*** - The Caldwell Luc approach involves an incision made in the **gingivolabial sulcus** of the upper jaw to access the anterior wall of the maxillary sinus. - This provides a direct and wide approach to the maxillary antrum for surgical procedures. *Inferior orbital rim* - An incision near the **inferior orbital rim** is generally used for orbital surgeries or approaches to the orbit, not directly for the maxillary antrum. - This approach offers access to the orbital floor and associated structures. *Nasal septum* - The **nasal septum** is a cartilaginous and bony wall separating the nostrils. Surgical approaches involving the septum are typically for septoplasty or access to the sphenoid sinus. - This anatomical location does not provide direct access to the maxillary antrum. *Cribriform plate* - The **cribriform plate** is a part of the ethmoid bone in the skull base and is associated with the sense of smell. - Access to this area is primarily for anterior cranial fossa surgeries and is entirely separate from the maxillary antrum.

Q: What is the treatment of choice for Deviated Nasal Septum (DNS) in adults?

Septoplasty. ***Septoplasty*** - **Septoplasty** is the surgical procedure of choice to correct a deviated nasal septum by **realigning the cartilage and bone** in the septum. - It is performed to improve nasal airflow and address symptoms like **nasal obstruction** or recurrent sinusitis. *Medical management with decongestants* - **Decongestants** provide temporary relief from nasal congestion but do not correct the underlying **anatomical deviation** of the septum. - Prolonged use of decongestants can lead to **rhinitis medicamentosa**, a rebound congestion. *Observation* - **Observation** is not an appropriate long-term solution for symptomatic DNS as the **anatomical deviation** will persist and symptoms are unlikely to improve spontaneously. - Patients with significant symptoms impacting their quality of life require active intervention rather than just monitoring. *Turbinoplasty* - **Turbinoplasty** is a procedure to reduce the size of the **turbinates**, which are bony structures in the nasal cavity that can contribute to nasal obstruction. - While it can be performed concurrently with septoplasty, it does not correct the **deviated septum itself**.

Q: Chemical labyrinthectomy by transtympanic route is done in Meniere's disease using which drug?

Gentamicin. ***Gentamicin*** - **Gentamicin** is an **aminoglycoside antibiotic** that is commonly used for chemical labyrinthectomy due to its **ototoxic** properties, particularly its selective toxicity to **vestibular hair cells** at lower doses. - When administered transtympanically, it achieves high concentrations in the **inner ear fluid**, effectively ablating the vestibular function and reducing severe vertigo in **Meniere's disease**. *Amikacin* - **Amikacin** is also an **aminoglycoside antibiotic** with ototoxic potential, but it is typically reserved for severe bacterial infections and is not the primary drug of choice for **chemical labyrinthectomy** in Meniere's disease. - While it can cause hearing loss, **gentamicin** has a more established and preferential effect on the **vestibular system** at therapeutic doses for Meniere's. *Amoxycillin* - **Amoxycillin** is a common **beta-lactam antibiotic** used for bacterial infections, and it does not possess **ototoxic** properties that would make it suitable for chemical labyrinthectomy. - It is primarily known for its antibacterial action and has no role in the management of vertigo in **Meniere's disease** via transtympanic administration. *Cyclosporine* - **Cyclosporine** is an **immunosuppressant drug** used to prevent organ rejection and treat autoimmune conditions; it does not have properties for chemical ablation of the labyrinth. - While some autoimmune components are sometimes considered in Meniere's disease, cyclosporine is not used for **transtympanic chemical labyrinthectomy**.

Q: The narrowest part of the nasal cavity is?

Internal nasal valve. ***Internal nasal valve*** - The **internal nasal valve** is considered the narrowest and most restrictive part of the **nasal airway**. - It is formed by the caudal border of the **upper lateral cartilage**, septum, and the head of the inferior turbinate. *Antrochoanal region* - The **antrochoanal region** is the posterior opening of the nasal cavity into the nasopharynx. - While it can be narrowed by polyps or mucosal swelling, it is not anatomically the **narrowest fixed point** of the nasal cavity. *1st nasal turbinate* - The **inferior turbinate** (often referred to as the 1st turbinate) can contribute to nasal resistance, especially when enlarged. - However, the turbinate itself is a structure that can vary in size and degree of congestion, but the **internal nasal valve** represents a consistently narrower anatomical choke point. *External nasal valve* - The **external nasal valve** is formed by the ala, columella, and nostril rim, and represents the entrance to the nasal cavity. - While it is a critical area for airflow, it is typically wider than the **internal nasal valve**.

Q: A patient with first-degree heart block presents with dizziness. What is the most appropriate management for this patient?

Observation and investigation of other causes. ***Observation and investigation of other causes*** - **First-degree heart block** is usually **asymptomatic** and benign, rarely causing dizziness or other symptoms. - The dizziness experienced by the patient is likely due to another underlying condition and warrants **further investigation** rather than direct intervention for the heart block [2], [3]. *Pacemaker insertion* - **Pacemaker insertion** is reserved for **symptomatic heart blocks** of higher degrees (e.g., Mobitz II or complete heart block) or those with significant hemodynamic compromise [1]. - Given that first-degree heart block is typically asymptomatic, inserting a pacemaker would be an **overtreatment** and unnecessary for this condition alone. *Isoprenaline* - **Isoprenaline** is a **beta-agonist** that increases heart rate and AV conduction, sometimes used in certain bradyarrhythmias. - However, for first-degree heart block, which is generally benign, pharmacologic intervention with agents like **isoprenaline** is not typically indicated and carries risks of adverse effects [2]. *Atropine* - **Atropine** is an anticholinergic drug used to **increase heart rate** by blocking vagal stimulation of the SA and AV nodes. - While it can improve AV conduction, it is not indicated for **asymptomatic first-degree heart block** or when symptoms like dizziness are unlikely to be directly caused by the block itself.

Q: Which human IgG subclass has the highest serum concentration?

IgG1. ***IgG1*** - **IgG1** constitutes approximately **60-70%** of the total IgG in human serum, making it the most abundant subclass. - Its high concentration reflects its crucial role in **neutralizing toxins**, agglutinating viruses, and opsonizing bacteria for phagocytosis. *IgG2* - **IgG2** makes up about **20-30%** of total IgG and is primarily important in protecting against **polysaccharide-encapsulated bacteria**. - While significant, its serum concentration is notably lower than that of IgG1. *IgG3* - **IgG3** is the least abundant IgG subclass, accounting for only **5-8%** of total IgG, and is characterized by a shorter half-life. - Despite its low concentration, it is highly efficient in activating the **complement system** due to its flexible hinge region. *IgG4* - **IgG4** comprises approximately **3-6%** of total IgG and is unique for its ability to undergo **Fab arm exchange**, leading to bispecific antibodies. - It does not activate complement and is often associated with allergy and protection against parasitic infections, but its concentration is significantly less than IgG1.

Q: Parasitosis of extraocular eye muscles is seen in?

Trichinella infection. ***Trichinella infection*** - **Trichinellosis** (caused by *Trichinella spiralis*) commonly involves the **extraocular muscles** during the muscle encystment phase [1]. - Ocular symptoms like **periorbital edema**, eosinophilic myositis of extraocular muscles, and subconjunctival hemorrhage are characteristic [1]. *Cysticercus infection* - **Cysticercosis**, caused by *Taenia solium* larvae, can affect the eye, predominantly forming **subretinal** or **vitreous cysts** [2]. - While it can involve orbital muscles, involvement of extraocular muscles is less typical and less specific than in trichinellosis [2]. *Amoebic infection* - **Amoebic infections** primarily cause **keratitis** (e.g., *Acanthamoeba*) [3] or can lead to granulomatous encephalitis in immunocompromised individuals. - They do not typically cause direct parasitosis of the extraocular muscles. *Ascariasis infection* - **Ascariasis**, caused by *Ascaris lumbricoides*, is an intestinal nematode and is not known to infect the extraocular muscles. - Ocular manifestations are rare and usually involve migration of adult worms to the orbit or eyelid, not muscle encystment. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 404-405. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 403-404. [3] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 735-736.

Q: HIV envelope is formed by:

Both. ***Both (Correct Answer)*** - The HIV envelope is a **composite structure** derived from both host and viral components - The **lipid bilayer** is acquired from the **host cell membrane** during viral budding - **Viral glycoproteins (gp120 and gp41)** encoded by the viral genome are inserted into this host-derived membrane - This makes the envelope a true hybrid structure essential for viral infectivity *Host cell (Incomplete)* - While the **lipid bilayer** of the envelope comes from the host cell membrane during budding, this alone does not form a functional envelope - The host cell provides the membrane scaffold but lacks the viral glycoproteins necessary for receptor binding and cell entry - Without viral proteins, the envelope cannot mediate infection *Virus (Incomplete)* - The virus encodes essential **envelope glycoproteins** (gp120 for receptor binding, gp41 for membrane fusion) - However, the virus does **not synthesize the lipid bilayer** itself - The viral genome lacks genes for lipid synthesis; the membrane must be acquired from the host *None of the options* - This is incorrect as the HIV envelope clearly requires contributions from **both** the host cell (lipid membrane) and the virus (glycoproteins)

Question 1

Which is the narrowest portion of the esophagus?

Accepted Answer

At the cricopharyngeal sphincter

Answer

At the diaphragmatic aperture

Answer

At the crossing of the left main bronchus

Answer

At the level of the aortic arch

Question 2

How often is the Sample Registration System conducted in India?

Accepted Answer

1 year

Answer

2 years

Answer

5 years

Answer

6 months

Question 3

Caldwell Luc Surgery has its approach to the maxillary antrum through ?

Accepted Answer

Gingivolabial sulcus

Answer

Inferior orbital rim

Answer

Nasal septum

Answer

Cribriform plate

Question 4

What is the treatment of choice for Deviated Nasal Septum (DNS) in adults?

Accepted Answer

Septoplasty

Answer

Medical management with decongestants

Answer

Observation

Answer

Turbinoplasty

Question 5

Chemical labyrinthectomy by transtympanic route is done in Meniere's disease using which drug?

Accepted Answer

Gentamicin

Answer

Amikacin

Answer

Amoxycillin

Answer

Cyclosporine

Question 6

The narrowest part of the nasal cavity is?

Accepted Answer

Internal nasal valve

Answer

Antrochoanal region

Answer

1st nasal turbinate

Answer

External nasal valve

Question 7

A patient with first-degree heart block presents with dizziness. What is the most appropriate management for this patient?

Accepted Answer

Observation and investigation of other causes

Answer

Pacemaker insertion

Answer

Isoprenaline

Answer

Atropine

Question 8

Which human IgG subclass has the highest serum concentration?

Accepted Answer

IgG1

Answer

IgG2

Answer

IgG3

Answer

IgG4

Question 9

Parasitosis of extraocular eye muscles is seen in?

Accepted Answer

Trichinella infection

Answer

Cysticercus infection

Answer

Amoebic infection

Answer

Ascariasis infection

Question 10

HIV envelope is formed by:

Accepted Answer

Both

Answer

Host cell

Answer

Virus

Answer

None of the options

NEET-PG 2015

Anatomy

Community Medicine

Dental

ENT

Internal Medicine

Microbiology