NEET-PG 2015 Practice Questions

Q: B cells are located in which region of lymph nodes?

Cortical follicles. ***Cortical follicles*** - **B cells** are predominantly found within the **cortical follicles** of lymph nodes, where they mature and become activated upon encountering antigens [2]. - These follicles can be primary (inactive) or secondary (active, containing **germinal centers** for B cell proliferation and differentiation). *Paracortical region* - The **paracortical region** is primarily occupied by **T cells** and is the site where T cells interact with antigen-presenting cells [1]. - While it's adjacent to B cell areas, it's not the primary location for B cells. *Medullary sinuses* - **Medullary sinuses** are channels in the medulla of the lymph node, containing macrophages and plasma cells, which are *differentiated B cells*. - They are not the primary residence for undifferentiated B cells. *Subcapsular region* - **Subcapsular region** is the space immediately beneath the capsule of the lymph node where lymph initially enters. - It contains macrophages and dendritic cells that sample antigens but is not a primary B cell zone.

Q: What is the end product of purine metabolism in most mammals?

Allantoin. ***Allantoin*** - **Allantoin** is the primary end product of **purine metabolism** in **most mammals** (except humans and higher primates), formed by the oxidation of uric acid by the enzyme **uricase**. - This conversion makes purine waste products more **water-soluble** and easier to excrete via the kidneys. - **Important clinical note:** Humans lack functional uricase, so **uric acid** is the end product in humans; this distinction is why hyperuricemia and gout occur in humans but not in most other mammals. *Glycogen* - **Glycogen** is a complex carbohydrate and serves as a primary **energy storage molecule** in animals, derived from glucose metabolism, not purine catabolism. - Its metabolism is regulated by hormones like **insulin** and **glucagon**, involved in maintaining blood glucose levels. *Pyrimidine* - **Pyrimidine** is a type of nitrogenous base, structurally distinct from purines, and is a component of DNA and RNA, not an end product of purine catabolism. - **Pyrimidine metabolism** involves the synthesis and breakdown of bases like cytosine, thymine, and uracil, which follows a separate biochemical pathway. *Histidine* - **Histidine** is an **essential amino acid**, a building block of proteins, and is involved in various metabolic processes, including histamine synthesis. - It plays no role as an end product of purine degradation; rather, its own metabolism leads to products like **urocanic acid**.

Q: Which of the following is not a feature of Poststreptococcal Glomerulonephritis (PSGN)?

Normal C3 level. ***Normal C3 level*** - In Post-streptococcal glomerulonephritis (PSGN), **C3 levels are typically decreased** due to complement consumption during the inflammatory process. [1] - A **normal C3 level** would not be consistent with PSGN, as it suggests no significant complement activation. *Increased urea* - Increased urea can occur due to **impaired renal function**, which is common in PSGN due to glomerular inflammation. [1] - It's a typical finding reflecting the kidneys' inability to excrete waste products properly. *HTN* - Hypertension is frequently associated with PSGN due to **volume overload** and activation of the renin-angiotensin system. [1] [2] - It is a common clinical feature that results from increased fluid retention. *Increased creatinine* - Increased creatinine levels indicate **renal impairment**, which is characteristic of PSGN as kidney function is affected during this condition. [1] - This finding highlights the reduction in glomerular filtration rate (GFR), typical in glomerulonephritis. [2]

Q: Subepithelial deposits in the kidney are primarily associated with which condition?

Post-Streptococcal Glomerulonephritis (PSGN). ***PSGN*** - Post-streptococcal glomerulonephritis (PSGN) is characterized by **subepithelial immune complex deposits** [1], typically after a streptococcal infection [1]. - It is associated with **hematuria**, **edema**, and elevated **anti-streptolysin O (ASO)** titers. *GPS* - Minimal change disease (often referred to as idiopathic nephrotic syndrome) does not primarily feature **subepithelial deposits** but rather **effacement of podocyte foot processes**. - Clinical presentation includes **nephrotic syndrome** symptoms, not glomerulonephritis like PSGN. *MPGN-1* - Membranoproliferative glomerulonephritis type 1 includes **subendothelial deposits** rather than subepithelial deposits associated with PSGN. - Symptoms often include **nephritic syndrome** and is commonly linked with conditions like **HCV infection**. *All* - While several conditions can show **deposits in kidney**, not all are characterized by **subepithelial deposits**, hence this option is inaccurate. - Each type of glomerular disease has specific types of deposits (immune complex vs. complement) associated with their pathophysiology. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Kidney, pp. 914-916.

Q: Osmotic fragility test is commonly used for which of the following conditions?

Hereditary spherocytosis. ***Hereditary spherocytosis*** - The **osmotic fragility test** helps in diagnosing hereditary spherocytosis, where **spherical red blood cells** are more prone to hemolysis in hypotonic solutions [1][2]. - This condition is characterized by **spherocytes** (abnormally shaped RBCs) leading to increased osmotic fragility [1][3]. *Megaloblastic anemia* - Megaloblastic anemia is primarily associated with **deficiencies in B12 or folate**, affecting the size and maturation of red blood cells, not their osmotic fragility. - The diagnosis focuses on **serum vitamin levels** and **bone marrow examination** rather than osmotic fragility. *Iron deficiency anemia* - Iron deficiency anemia features **microcytic** and **hypochromic RBCs**, and its diagnosis relies on **iron studies**, not osmotic fragility tests. - The osmotic fragility test does not reveal significant changes in red blood cells for this condition. *Aplastic anemia* - Aplastic anemia involves **pancytopenia** due to bone marrow failure and does not typically show altered osmotic fragility. - The diagnosis is confirmed through **bone marrow biopsy**, not by assessing osmotic fragility. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 597-598. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, pp. 640-641. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Red Blood Cell and Bleeding Disorders, p. 638.

Q: Which of the following is the longest acting carbapenem?

Ertapenem. ***Ertapenem*** - **Ertapenem** has the **longest half-life** among the carbapenems, allowing for once-daily dosing. - Its prolonged action is due to its **chemical structure**, which provides high protein binding and reduced renal clearance compared to other carbapenems. *Imipenem* - **Imipenem** has a **relatively short half-life** and requires co-administration with cilastatin to prevent its renal metabolism by dehydropeptidase-1. - Its short duration of action necessitates **frequent dosing**, typically every 6 to 8 hours. *Meropenem* - **Meropenem** has a **shorter half-life** than ertapenem, generally requiring dosing every 8 hours. - Although it does not require cilastatin, its pharmacokinetic profile is not as extended as ertapenem's. *Doripenem* - **Doripenem** also has a **shorter half-life** than ertapenem, necessitating administration every 8 hours. - Its spectrum of activity is similar to meropenem, but it does not offer the same extended duration of action.

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: Vital capacity is measured by:

Spirometer. ***Spirometer*** - A **spirometer** is a device used to measure lung volumes and capacities, including **vital capacity**. - It measures the volume of air inspired and expired by evaluating mechanical changes in the volume of air in the lungs. *Plethysmography* - **Plethysmography** is primarily used to measure **residual volume** and **total lung capacity**, not vital capacity directly. - This method measures changes in body volume to infer changes in lung volume. *Gas-dilution method* - The **gas-dilution method**, typically using helium, is used to measure the **functional residual capacity (FRC)** and subsequently calculate residual volume and total lung capacity. - It involves rebreathing a known concentration of gas to determine the volume of gas already in the lungs. *Nitrogen washout technique* - The **nitrogen washout technique** is also used to measure **functional residual capacity (FRC)** and detect uneven ventilation. - It involves breathing 100% oxygen to wash out all nitrogen from the lungs, allowing for calculation of lung volumes.

Q: What do motor evoked potentials primarily assess?

Central motor pathways. ***Central motor pathways*** - **Motor evoked potentials (MEPs)** are generated by electrical or magnetic stimulation of the **motor cortex** and primarily assess the integrity of **central motor pathways**, specifically the **corticospinal tracts**. - MEPs are the **gold standard** for monitoring **upper motor neuron** function during neurosurgical and spinal procedures. - The technique is most sensitive to dysfunction in the **brain and spinal cord** (central nervous system), making this their primary clinical utility. *Peripheral motor pathways* - While MEPs do eventually activate peripheral motor neurons to produce muscle responses, they are **not the primary tool** for assessing peripheral pathways. - **Nerve conduction studies (NCS)** and **electromyography (EMG)** are direct and more specific measures for evaluating peripheral motor nerve function. *Both central and peripheral motor pathways* - Although MEPs provide information about the entire motor pathway from cortex to muscle, their **primary diagnostic strength and clinical application** is in detecting dysfunction within the **central nervous system**. - The latency and amplitude of MEPs are most sensitive to **conduction abnormalities along the corticospinal tract**, not peripheral nerves. *Muscle regeneration* - MEPs do **not assess muscle regeneration** or intrinsic muscle health. - **Electromyography (EMG)** with needle examination and **muscle biopsy** are the appropriate methods to evaluate muscle regeneration and myopathic processes.

Q: Amount of blood loss in Stage I of hemorrhagic shock is -

<15%. ***<15%*** - Stage I (Class I) hemorrhagic shock is characterized by **minimal blood loss of up to 15%** of total blood volume (up to 750 mL in a 70 kg adult). - This is the **universally accepted ATLS definition** for Class I hemorrhage. - At this level, compensatory mechanisms maintain normal vital signs with minimal clinical manifestations. - Patients typically show minimal or no symptoms, with possible mild tachycardia only. * 100 bpm), tachypnea, and decreased pulse pressure, but blood pressure remains normal. - This is too broad to specifically define Stage I. * 120 bpm), altered mental status, and decreased urine output. - This is far beyond the compensated Stage I definition.

Question 1

B cells are located in which region of lymph nodes?

Accepted Answer

Cortical follicles

Answer

Paracortical region

Answer

Subcapsular region

Answer

Medullary sinuses

Question 2

What is the end product of purine metabolism in most mammals?

Accepted Answer

Allantoin

Answer

Glycogen

Answer

Pyrimidine

Answer

Histidine

Question 3

Which of the following is not a feature of Poststreptococcal Glomerulonephritis (PSGN)?

Accepted Answer

Normal C3 level

Answer

HTN

Answer

Increased urea

Answer

Increased creatinine

Question 4

Subepithelial deposits in the kidney are primarily associated with which condition?

Accepted Answer

Post-Streptococcal Glomerulonephritis (PSGN)

Answer

None of these conditions are associated with subepithelial deposits.

Answer

Membranoproliferative Glomerulonephritis (MPGN) Type I

Answer

Goodpasture's Syndrome (GPS)

Question 5

Osmotic fragility test is commonly used for which of the following conditions?

Accepted Answer

Hereditary spherocytosis

Answer

Megaloblastic anemia

Answer

Aplastic anemia

Answer

Iron deficiency anemia

Question 6

Which of the following is the longest acting carbapenem?

Accepted Answer

Ertapenem

Answer

Imipenem

Answer

Meropenem

Answer

Doripenem

Question 7

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 8

Vital capacity is measured by:

Accepted Answer

Spirometer

Answer

Plethysmography

Answer

Nitrogen washout technique

Answer

Gas-dilution method

Question 9

What do motor evoked potentials primarily assess?

Accepted Answer

Central motor pathways

Answer

Both central and peripheral motor pathways

Answer

Muscle regeneration

Answer

Peripheral motor pathways

Question 10

Amount of blood loss in Stage I of hemorrhagic shock is -

Accepted Answer

<15%

Answer

<10%

Answer

<30%

Answer

<40%

NEET-PG 2015

Anatomy

Biochemistry

Internal Medicine

Pathology

Pharmacology

Physiology

Surgery