Neuroanatomy Practice Questions

Q: Nodular regenerative hyperplasia of the liver is most commonly associated with which of the following conditions?

Drug-induced liver injury. **Explanation:** **Nodular Regenerative Hyperplasia (NRH)** is a rare clinicopathologic entity characterized by the widespread transformation of normal liver parenchyma into small, regenerative nodules without significant fibrosis. **Why Option A is Correct:** The pathogenesis of NRH is primarily linked to **obliterative portal venopathy**, which leads to uneven blood distribution. Areas with decreased perfusion atrophy, while areas with preserved flow undergo compensatory hyperplasia. **Drug-induced liver injury (DILI)**, specifically from medications like **Azathioprine**, 6-thioguanine, and certain chemotherapeutic agents (e.g., Oxaliplatin), is a well-documented cause of this vascular disruption. Other major associations include systemic inflammatory diseases (RA, SLE) and myeloproliferative disorders. **Why Other Options are Incorrect:** * **B & C (Alcoholic Hepatitis & Hepatitis B):** These conditions typically lead to **Cirrhosis**. Unlike NRH, cirrhosis is characterized by diffuse nodules separated by dense **fibrous septa**. NRH is often misdiagnosed as cirrhosis clinically, but the absence of fibrosis on biopsy is the key differentiator. * **D (Autoimmune Hepatitis):** While autoimmune conditions like RA are associated with NRH, Autoimmune Hepatitis itself typically presents with interface hepatitis and progressive fibrosis leading to cirrhosis, rather than the specific vascular-driven nodularity of NRH. **High-Yield Pearls for NEET-PG:** * **Key Histology:** Small regenerative nodules **without** fibrous bands (Reticulin stain is essential to visualize the collapsed framework). * **Clinical Presentation:** Often presents as **Non-cirrhotic Portal Hypertension** (splenomegaly, varices) with relatively preserved liver function tests. * **Associated Drugs:** Azathioprine (most common), Highly Active Antiretroviral Therapy (HAART), and Busulfan.

Q: Which of the following is known as the guardian of the genome?

P53. The correct answer is **A. P53**. **Why P53 is the "Guardian of the Genome":** The **TP53 gene** encodes the p53 protein, a critical tumor suppressor [1]. It acts as a molecular "gatekeeper" that monitors DNA integrity. When DNA damage is detected (via stressors like radiation or toxins), p53 levels rise and trigger one of three pathways: 1. **Quiescence:** Temporary cell cycle arrest (at the G1-S checkpoint) to allow for DNA repair [4]. 2. **Senescence:** Permanent cell cycle arrest. 3. **Apoptosis:** Programmed cell death if the damage is irreparable (via the BAX/BCL-2 pathway) [2, 3]. By preventing cells with mutated DNA from proliferating, p53 maintains genomic stability. **Analysis of Incorrect Options:** * **B. Mdm2:** This is the primary **negative regulator** of p53. It acts as an E3 ubiquitin ligase that targets p53 for degradation in healthy cells. Overexpression of Mdm2 can lead to cancer by silencing p53. * **C. P14 (ARF):** This protein acts as a tumor suppressor by **inhibiting Mdm2**, thereby stabilizing p53. It is a "helper" but not the guardian itself. * **D. ATM (Ataxia-Telangiectasia Mutated):** This is a kinase that senses double-stranded DNA breaks. It phosphorylates p53 to activate it, acting as a **sensor** rather than the central effector. **High-Yield Clinical Pearls for NEET-PG:** * **Li-Fraumeni Syndrome:** A germline mutation in TP53 leading to a high risk of multiple early-onset cancers (Sarcoma, Breast, Leukemia, Adrenal - **SBLA** syndrome) [3]. * **Most Common Mutation:** TP53 is the most frequently mutated gene in human cancers (>50% of all tumors) [1]. * **HPV Link:** The E6 protein of Human Papillomavirus (HPV) causes degradation of p53, leading to cervical cancer.

Q: Which of the following cells are not seen in the cerebellar cortex?

Magnocellular cells. The cerebellar cortex is organized into three distinct layers: the **Molecular layer** (outer), the **Purkinje cell layer** (middle), and the **Granular layer** (inner) [1]. ### Why Magnocellular cells is the correct answer: **Magnocellular cells** are not found in the cerebellar cortex. These are large neurons located in the **Red Nucleus** (of the midbrain) and the **Lateral Geniculate Nucleus (LGN)** of the thalamus. In the red nucleus, they give rise to the rubrospinal tract, while in the LGN, they form the magnocellular pathway responsible for detecting motion and depth. ### Why the other options are incorrect: * **Purkinje cells (Option A):** These are the hallmark cells of the cerebellum, located in the middle layer [1]. They are the only cells that provide **inhibitory output** (via GABA) from the cerebellar cortex to the deep cerebellar nuclei [1]. * **Stellate cells (Option B):** These are inhibitory interneurons located in the outer **Molecular layer** [1]. * **Basket cells (Option C):** Also located in the **Molecular layer**, these cells provide powerful inhibitory input to the cell bodies of Purkinje cells [1]. ### High-Yield Facts for NEET-PG: * **Layers of Cerebellar Cortex (Outer to Inner):** Molecular $\rightarrow$ Purkinje $\rightarrow$ Granular. * **Five Cell Types:** Purkinje, Granule, Stellate, Basket, and Golgi cells [1]. * **Excitatory vs. Inhibitory:** All cells in the cerebellar cortex are **inhibitory** EXCEPT for **Granule cells**, which are excitatory (using Glutamate) [1]. * **Afferent Fibers:** **Climbing fibers** (from inferior olivary nucleus) and **Mossy fibers** (from all other sources) are both excitatory [1]. * **Clinical Correlation:** Damage to the cerebellum results in **ipsilateral** symptoms (Ataxia, Hypotonia, Nystagmus, Intention tremor) [1].

Q: What are the findings of trigeminal nerve injury?

Loss of blinking reflex of eye. **Explanation:** The **Trigeminal nerve (CN V)** is the largest cranial nerve and provides sensory innervation to the face and motor innervation to the muscles of mastication. **1. Why Option B is Correct:** The **Blinking (Corneal) Reflex** consists of an afferent and an efferent limb. The **Ophthalmic division (V1)** of the trigeminal nerve carries the afferent (sensory) impulse from the cornea to the brainstem. The **Facial nerve (CN VII)** provides the efferent (motor) limb to the orbicularis oculi muscle. An injury to the trigeminal nerve disrupts the sensory input, resulting in a loss of the blinking reflex when the cornea is touched. **2. Why Incorrect Options are Wrong:** * **A & D (Pupillary dilation and Ptosis):** These are associated with the **Oculomotor nerve (CN III)** or sympathetic chain injury (Horner’s Syndrome). CN III controls the sphincter pupillae (constriction) and levator palpebrae superioris (eyelid elevation). * **C (Normal jaw reflex):** The **Jaw-jerk reflex** is a monosynaptic stretch reflex where both the afferent and efferent limbs are mediated by the **Mandibular division (V3)** of the trigeminal nerve. In a trigeminal nerve injury (specifically the motor root or V3), this reflex would be **absent or diminished**, not normal. **Clinical Pearls for NEET-PG:** * **Trigeminal Neuralgia (Tic Douloureux):** Characterized by stabbing, lancinating pain in the V2 or V3 distribution. * **Muscle Deviation:** In a lower motor neuron lesion of CN V, the jaw deviates **towards the side of the lesion** when opened due to the action of the contralateral lateral pterygoid muscle. * **Mesencephalic Nucleus:** This is the only site in the CNS that contains cell bodies of primary sensory neurons (proprioception for the jaw reflex).

Q: Which colloid-based formula is most commonly used in burn management?

Muir and Barclay formula. The management of major burns focuses on aggressive fluid resuscitation to counteract "burn shock" caused by increased capillary permeability. **1. Why Muir and Barclay is correct:** The **Muir and Barclay formula** is the classic **colloid-based** resuscitation protocol. It utilizes Plasma (or albumin) and is calculated based on the formula: * *(Total Area of Burn % × Weight in kg) / 2 = Volume of one aliquot (in ml).* This volume is administered over six specific time periods (36 hours total), making it distinct from crystalloid-heavy regimens. [1] **2. Analysis of Incorrect Options:** * **Parkland Formula (and Baxter’s Formula):** These are essentially synonymous and represent the most widely used **crystalloid-based** protocols. They utilize Ringer’s Lactate (4 ml/kg/% TBSA) over the first 24 hours. No colloids are used in the initial 24 hours in these formulas. * **Wallace Formula:** This is not a resuscitation formula but a method for estimating the **Total Body Surface Area (TBSA)** involved in a burn, commonly known as the **"Rule of Nines."** **3. NEET-PG High-Yield Pearls:** * **Fluid of Choice:** Ringer’s Lactate is the preferred crystalloid for the first 24 hours (Parkland). * **Monitoring:** The most reliable indicator of adequate fluid resuscitation is **Urinary Output** (Target: 0.5–1 ml/kg/hr in adults; 1 ml/kg/hr in children). [1] * **Modified Brooke Formula:** Another crystalloid formula (2 ml/kg/% TBSA). * **Colloid Timing:** In modern practice, colloids are generally introduced *after* the first 24 hours when capillary permeability begins to normalize. [1]

Q: The attachment of eukaryotic mRNA to the ribosome is mediated through which of the following?

Guanyl cap. **Explanation:** In eukaryotes, the initiation of translation begins with the recognition of the **5' Guanyl cap** (7-methylguanosine cap) by the eukaryotic initiation factor 4E (eIF4E). This cap-binding complex then recruits the 40S ribosomal subunit to the mRNA. This process is essential for the ribosome to scan the mRNA for the start codon (AUG). **Analysis of Options:** * **Guanyl cap (Correct):** It serves as the primary recognition signal for the ribosome in eukaryotes. It also protects mRNA from exonuclease degradation. * **Poly-A tail:** Located at the 3' end, it enhances stability and translation efficiency but is not the primary site for initial ribosomal attachment. * **tRNA:** These are adapter molecules that carry amino acids to the ribosome; they do not mediate the initial attachment of the mRNA strand to the ribosome itself. * **Shine-Dalgarno sequence:** This is a **prokaryotic** feature. It is a purine-rich sequence located upstream of the start codon that aligns the 16S rRNA of the 30S ribosomal subunit. Eukaryotes use the **Kozak consensus sequence** for a similar purpose, but the initial binding is cap-dependent. **Clinical Pearls for NEET-PG:** * **Kozak Sequence:** In eukaryotes, the ribosome identifies the correct AUG start codon by recognizing the Kozak sequence (5'-ACCAUGG-3'). * **Cap-Independent Translation:** Some viral and cellular mRNAs can bypass the guanyl cap requirement using an **IRES (Internal Ribosome Entry Site)**. * **eIF4F Complex:** This is the "cap-binding complex" consisting of eIF4E (binds cap), eIF4A (helicase), and eIF4G (scaffold). Overexpression of eIF4E is often linked to cancer progression.

Q: The primary palate is formed from which embryological structure?

Medial nasal prominences. ### Explanation The development of the face and palate occurs between the 4th and 10th weeks of gestation. Understanding the derivatives of the five facial primordia is crucial for NEET-PG. **Why Option A is Correct:** The **primary palate** (also known as the premaxilla) is formed by the fusion of the two **medial nasal prominences**. These prominences merge in the midline to form the **intermaxillary segment**. This segment gives rise to three components: 1. The philtrum of the upper lip. 2. The four upper incisor teeth and associated gingiva. 3. The triangular **primary palate**, which lies anterior to the incisive foramen. **Why Other Options are Incorrect:** * **B. Lateral nasal prominences:** These form the alae (sides) of the nose. They do not contribute to the palate or the upper lip. * **C. Maxillary prominences:** These give rise to the **secondary palate** (via palatal shelves), the lateral parts of the upper lip, the cheeks, and the maxilla. * **D. Mandibular prominences:** These fuse in the midline to form the lower jaw, lower lip, and the chin. --- ### High-Yield Clinical Pearls for NEET-PG: * **Secondary Palate:** Formed by the fusion of **palatal shelves** (outgrowths of the maxillary prominences). * **Incisive Foramen:** This serves as the anatomical landmark separating the primary and secondary palate. * **Cleft Lip:** Results from the failure of the **maxillary prominence** to fuse with the **medial nasal prominence**. * **Cleft Palate:** Results from the failure of the **palatal shelves** (maxillary prominence) to fuse with each other or with the primary palate. * **Naso-lacrimal duct:** Formed at the junction of the maxillary and lateral nasal prominences (the nasolacrimal groove).

Q: The epithelium of the cornea is:

Stratified squamous non-keratinized. The cornea is the transparent front part of the eye that covers the iris and pupil. Its outermost layer, the **corneal epithelium**, is composed of **stratified squamous non-keratinized epithelium** [1]. This specific tissue type is ideal because it provides a smooth, protective barrier against mechanical trauma while remaining moist and transparent to allow light passage—a necessity for vision [1], [3]. **Why the correct answer is right:** * **Stratified:** Multiple layers (usually 5–6) allow for constant cell turnover and protection [1]. * **Squamous:** The superficial cells are flat. * **Non-keratinized:** Unlike the skin, the cornea must remain moist. Keratin would make the cornea opaque and dry, leading to blindness. **Analysis of incorrect options:** * **A. Pseudostratified:** Found primarily in the respiratory tract (ciliated). It consists of a single layer of cells of varying heights, which would not provide sufficient protection for the ocular surface. * **B. Transitional (Urothelium):** Exclusive to the urinary tract (e.g., bladder). It is designed for distension and stretching, which is not a requirement for the rigid cornea. * **C. Stratified squamous keratinized:** This is found in the **epidermis of the skin**. The presence of keratin provides water-proofing and toughness but results in opacity. **High-Yield Clinical Pearls for NEET-PG:** * **Corneal Layers (Outer to Inner):** Epithelium $\rightarrow$ Bowman’s membrane $\rightarrow$ Stroma (thickest layer) $\rightarrow$ Descemet’s membrane $\rightarrow$ Endothelium [1], [3]. * **Regeneration:** The corneal epithelium is replaced every 7 days. Stem cells for this regeneration are located in the **limbus** (palisades of Vogt) [2]. * **Nerve Supply:** The cornea is one of the most sensitive tissues in the body, supplied by the **long ciliary nerves** (branches of the Ophthalmic nerve, CN V1).

Question 1

Nodular regenerative hyperplasia of the liver is most commonly associated with which of the following conditions?

Accepted Answer

Drug-induced liver injury

Answer

Alcoholic hepatitis

Answer

Hepatitis B infection

Answer

Autoimmune hepatitis

Question 2

Which of the following is known as the guardian of the genome?

Accepted Answer

P53

Answer

Mdm2

Answer

P14

Answer

ATM

Question 3

All are derivatives of the neural crest except?

Accepted Answer

Neurons of sensory ganglia of cranial nerves V, VII, VIII, IX, and X

Answer

Dorsal nerve root ganglia

Answer

Neurons of sympathetic ganglia

Answer

Neurons of parasympathetic ganglia

Question 4

Which of the following cells are not seen in the cerebellar cortex?

Accepted Answer

Magnocellular cells

Answer

Purkinje cells

Answer

Stellate cells

Answer

Basket cells

Question 5

What are the findings of trigeminal nerve injury?

Accepted Answer

Loss of blinking reflex of eye

Answer

Pupillary dilation

Answer

Normal jaw reflex

Answer

Ptosis

Question 6

Which colloid-based formula is most commonly used in burn management?

Accepted Answer

Muir and Barclay formula

Answer

Parkland formula

Answer

Baxter's formula

Answer

Wallace formula

Question 7

The attachment of eukaryotic mRNA to the ribosome is mediated through which of the following?

Accepted Answer

Guanyl cap

Answer

Poly-A tail

Answer

tRNA

Answer

Shine-Dalgarno sequence

Question 8

The floor of the fourth ventricle is NOT formed by which of the following structures?

Accepted Answer

Posterior surface of pons

Answer

Sulcus limitans

Answer

Anterior medullary velum

Answer

Posterior surface of medulla

Question 9

The primary palate is formed from which embryological structure?

Accepted Answer

Medial nasal prominences

Answer

Lateral nasal prominences

Answer

Maxillary prominences

Answer

Mandibular prominences

Question 10

The epithelium of the cornea is:

Accepted Answer

Stratified squamous non-keratinized

Answer

Pseudostratified

Answer

Transitional

Answer

Stratified squamous keratinized

Neuroanatomy — MCQs

Neuroanatomy — MCQs

On this page

Practice by Chapter

Want unlimited practice?