NEET-PG 2015 Practice Questions

Q: Base of sphenoid fuses with occiput at the age of -

20 years. ***20 years*** - The **spheno-occipital synchondrosis** typically fuses by the age of **20 to 25 years**, marking the cessation of growth in the cranial base. - This fusion is an important indicator of skeletal maturity and is often used in **forensic anthropology** for age estimation. *30 years* - Fusion of the **spheno-occipital synchondrosis** beyond the early twenties is considered late and is not the typical age for this event. - By 30 years, most cranial sutures and synchondroses are already fused. *40 years* - At 40 years of age, the **spheno-occipital synchondrosis** would have been completely fused for many years, making this an incorrect age for the fusion process itself. - This age is well past the usual developmental timeframe for cranial base closure. *50 years* - Fusion at 50 years would be an **anomalous finding** as this synchondrosis is known to fuse much earlier in life. - By this age, the skull is fully mature, and fusion events of this nature have long since completed.

Q: What is a distinguishing feature of reticulocytes?

Presence of residual RNA and ribosomes. ***Presence of residual RNA and ribosomes*** - This is the **defining and most distinguishing feature** of reticulocytes that differentiates them from mature red blood cells. - Reticulocytes contain residual **ribosomal RNA** and other organelles that are lost when they mature into erythrocytes. - This residual RNA forms a **reticular (network-like) pattern** when stained with supravital stains like **new methylene blue** or **brilliant cresyl blue**, which is the basis for their name and identification. - The presence of RNA allows for **reticulocyte counting**, an important marker of bone marrow erythropoietic activity. *Slightly larger in size than RBCs* - While reticulocytes may be slightly larger (polychromatophilic appearance), size variation is **not specific** and overlaps significantly with mature RBCs. - Size is not a reliable distinguishing feature and is not used for identification or counting. *Mature in bone marrow* - Reticulocytes are **released from the bone marrow** as immature red cells and complete their maturation in the **peripheral circulation** over 24-48 hours. - They do not fully mature in the bone marrow; their presence in peripheral blood is normal. *Constitute approximately 1% of the red cells* - Normal reticulocyte count is **0.5-2%** (or approximately 1%) of total red blood cells in healthy adults. - This is a **population characteristic** indicating normal erythropoietic activity, not a distinguishing cellular feature.

Q: All of the following are features of granulomatous thyroiditis except?

Painless. ***Painless*** - Granulomatous thyroiditis is characterized by **painful** thyroid gland inflammation, which is a distinguishing feature. - Thus, describing it as **painless** contradicts the typical clinical presentation. *Hyperthyroidism* - Granulomatous thyroiditis may lead to **hyperthyroidism** initially due to the release of thyroid hormones from damaged follicles [1]. - However, this condition can also lead to transient thyroid function changes or even permanent hypothyroidism later on [1]. *Hypothyroidism* - While **hypothyroidism** can occur post-thyroiditis, it is not a feature of granulomatous thyroiditis at the outset like the **painless** descriptor. - This condition often starts with hyperthyroid symptoms and may evolve later, differing from primary hypothyroid disorders. *Giant cells on histology* - Histological examination typically reveals **multinucleated giant cells**, a hallmark of granulomatous inflammation, as seen in this thyroid condition. - This significant finding helps in differentiating it from other thyroid disorders. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Endocrine System, pp. 1091-1092.

Q: What is the first cellular response observed after a sharp nerve cut?

Chromatolysis. ***Chromatolysis*** - **Chromatolysis** is the dissolution of the Nissl bodies (rough endoplasmic reticulum) in the neuron cell body following axonal injury, which is the **first observable cellular response** [1]. - This process is a preparatory step for neuronal regeneration, indicating the cell's attempt to repair the damaged axon [1]. *Polymorphic arrangement* - This term is not typically used to describe an immediate cellular response to a nerve cut; it might refer to diverse cell shapes or arrangements in different contexts but is not a recognized initial post-injury event. - The neuron's immediate response involves changes within the cell body, not a re-arrangement of its cellular structure with other cells. *Increased protein synthesis* - While increased protein synthesis does occur during neuronal repair and regeneration, it is a consequence of chromatolysis and part of a later, more sustained response, not the very first visible cellular change [1]. - **Chromatolysis precedes** and facilitates the subsequent increase in protein synthesis necessary for axonal regrowth [1]. *Macrophage activation* - **Macrophage activation** is a crucial part of the inflammatory response and debris clearance following nerve injury, but it is not the *first cellular response* of the neuron itself [2]. - Macrophages migrate to the site of injury hours to days after the initial insult, whereas chromatolysis begins within the neuron's cell body much earlier [2]. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1254-1256. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 697-698.

Q: Reversible change from one cell type to another is known as -

Metaplasia. ***Metaplesia*** - Refers to the **reversible change** from one cell type to another in response to chronic irritation or damage [1][2]. - It often occurs as an adaptive response in **epithelial tissues**, such as in the respiratory tract in smokers [1][2]. *Hypertrophy* - Represents an **increase in cell size** rather than a change in cell type [2]. - It is often a response to increased functional demand, as seen in **cardiac muscle** in athletes. *Hyperplesia* - Refers to an **increase in cell number** within a tissue or organ, not a change in cell type [2]. - Common in conditions such as **benign prostatic hyperplasia** but does not involve differentiation into other cell types. *Dysplasia* - Indicates an **abnormal growth or development** of cells, leading to disordered morphology rather than a transformation into another cell type. - It is often a precursor to cancer but does not signify the reversible nature of metaplasia. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Cellular Responses to Stress and Toxic Insults: Adaptation, Injury, and Death, p. 49. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 85-92.

Q: Which of the following is a long-acting beta-2 agonist?

Formoterol. ***Formoterol*** - **Formoterol** is a **long-acting beta-2 agonist (LABA)** commonly used in the treatment of asthma and COPD. - It provides **bronchodilation** for up to 12 hours due to its high lipophilicity, allowing it to remain in the cell membrane and continuously activate beta-2 receptors. *Isoprenaline (non-selective adrenergic agonist)* - **Isoprenaline** is a **non-selective beta-adrenergic agonist**, meaning it activates both beta-1 and beta-2 receptors. - It is **short-acting** and primarily used as a vasodilator or to stimulate heart rate, not as a long-acting bronchodilator. *Ephedrine (non-selective adrenergic agonist)* - **Ephedrine** is a **mixed-acting sympathomimetic amine** that increases the release of norepinephrine and directly stimulates alpha and beta receptors. - It has a short duration of action and is primarily used as a decongestant or bronchodilator in emergency situations, not as a long-acting agent. *Salbutamol (short-acting beta-2 agonist)* - **Salbutamol** is a **short-acting beta-2 agonist (SABA)**, providing rapid onset but a short duration of action (typically 4-6 hours). - It is used for **relieving acute bronchospasm** and is not considered a long-acting medication for maintenance therapy.

Q: Which anti-cholinesterase drug is known for its central nervous system activity?

Physostigmine. ***Physostigmine*** - Unlike most other anti-cholinesterases, **physostigmine** is a **tertiary amine** and is relatively lipid-soluble, allowing it to cross the **blood-brain barrier**. [2] - Its ability to increase acetylcholine in the CNS makes it useful in treating anticholinergic toxicity (e.g., atropine overdose). [2] *Pyridostigmine* - **Pyridostigmine** is a **quaternary amine** and does not readily cross the blood-brain barrier, primarily acting peripherally. - It is mainly used in the long-term management of **myasthenia gravis**. *Edrophonium* - **Edrophonium** is a very short-acting **quaternary amine** that does not cross the blood-brain barrier. [1] - It is primarily used for the **diagnosis of myasthenia gravis** (Tensilon test) due to its rapid onset and short duration of action. [1] *Neostigmine* - **Neostigmine** is also a **quaternary amine** with poor lipid solubility, meaning it has minimal central nervous system activity. [2] - It is commonly used to reverse the effects of **non-depolarizing neuromuscular blockers** and in the treatment of **myasthenia gravis**.

Q: Inhibition of heart by vagus is mediated by which receptors?

M2. ***M2*** - The **vagus nerve** primarily mediates its inhibitory effects on the heart through **muscarinic M2 receptors**. - Activation of M2 receptors by **acetylcholine** (released from the vagus nerve) decreases heart rate and contractility. *M1* - **M1 receptors** are primarily found in neuronal tissue and glands, playing a role in **gastric acid secretion** and cognitive functions. - They are not the primary muscarinic subclass responsible for vagal inhibition of the heart. *NN* - **NN receptors** are **nicotinic receptors** found on postganglionic neurons in autonomic ganglia. - They are involved in **ganglionic transmission** and are not directly responsible for efferent vagal effects on the heart. *NM* - **NM receptors** are **nicotinic receptors** found at the **neuromuscular junction** of skeletal muscles. - Their activation leads to **skeletal muscle contraction**, and they have no role in regulating heart function.

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

Base of sphenoid fuses with occiput at the age of -

Accepted Answer

20 years

Answer

30 years

Answer

40 years

Answer

50 years

Question 2

Which of the following statements about peripheral nerve injury is false?

Accepted Answer

Neuropraxia is irreversible

Answer

Wallerian degeneration starts in axonotmesis

Answer

Neurotmesis is the most severe form of injury

Answer

Epineurium is intact in axonotmesis

Question 3

What is a distinguishing feature of reticulocytes?

Accepted Answer

Presence of residual RNA and ribosomes

Answer

Slightly larger in size than RBCs

Answer

Mature in bone marrow

Answer

Constitute approximately 1% of the red cells

Question 4

All of the following are features of granulomatous thyroiditis except?

Accepted Answer

Painless

Answer

Hyperthyroidism

Answer

Giant cells on histology

Answer

Hypothyroidism

Question 5

What is the first cellular response observed after a sharp nerve cut?

Accepted Answer

Chromatolysis

Answer

Polymorphic arrangement

Answer

Increased protein synthesis

Answer

Macrophage activation

Question 6

Reversible change from one cell type to another is known as -

Accepted Answer

Metaplasia

Answer

Hypertrophy

Answer

Dysplasia

Answer

Hyperplasia

Question 7

Which of the following is a long-acting beta-2 agonist?

Accepted Answer

Formoterol

Answer

Isoprenaline

Answer

Ephedrine

Answer

Salbutamol

Question 8

Which anti-cholinesterase drug is known for its central nervous system activity?

Accepted Answer

Physostigmine

Answer

Edrophonium

Answer

Pyridostigmine

Answer

Neostigmine

Question 9

Inhibition of heart by vagus is mediated by which receptors?

Accepted Answer

M2

Answer

M1

Answer

NN

Answer

NM

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

Forensic Medicine

Pathology

Pharmacology

Physiology

Surgery