Neuroanatomy Practice Questions

Q: Name the center shown as $X$ in the cut section of medulla which is responsible for control of respiration.

Pre-Botzinger Complex. ***Pre-Botzinger Complex*** - The **pre-Bötzinger complex** in the medulla is crucial for generating the **respiratory rhythm** and is the primary site of inspiratory rhythmogenesis. - It is located ventral to the nucleus ambiguus and contains **pacemaker neurons** that fire spontaneously. *Pneumotaxic centre* - The **pneumotaxic center** is located in the **pons**, specifically the upper pons, and primarily regulates respiratory rate and depth. - It works by sending inhibitory signals to the inspiratory center, thereby **limiting inspiration**. *Nucleus Para-brachialis* - The **nucleus parabrachialis** is located in the pons and includes the pneumotaxic center, affecting the **transition between inspiration and expiration**. - It helps in fine-tuning respiratory patterns rather than initiating the basic rhythm. *Dorsal group of respiratory neurons* - The **dorsal respiratory group (DRG)**, located in the medulla, primarily controls **inspiration** and receives sensory input from chemoreceptors and mechanoreceptors. - While it initiates the basic inspiratory muscle activity, the pre-Bötzinger complex is considered the rhythm generator. *Ventral group of respiratory neurons* - The **ventral respiratory group (VRG)**, located in the ventrolateral medulla, contains neurons responsible for both **inspiration and expiration**. - The pre-Bötzinger complex is actually part of the VRG and serves as the **rhythm-generating center** within this larger group.

Q: The marked area in the image given below is associated with which part of brain cortex?

Striate cortex. ***Striate cortex*** - The image points to the **calcarine sulcus**, a prominent landmark on the medial surface of the occipital lobe. - The **striate cortex**, also known as the primary visual cortex (V1), is located along the banks of the calcarine sulcus. *Hippocampus* - The hippocampus is a structure located in the **medial temporal lobe**, involved in memory formation. - It would be found deeper within the temporal lobe, not on the medial surface of the occipital lobe as indicated. *Dentate nucleus* - The dentate nucleus is a **deep cerebellar nucleus**, located within the cerebellum. - The arrow points to an area of the cerebral cortex, not the cerebellum. *Orbital cortex* - The orbital cortex (or orbitofrontal cortex) is located in the **ventral-anterior part of the frontal lobes**. - It is involved in decision-making and reward, and its location is far removed from the area indicated by the arrow, which is in the posterior part of the brain. *Entorhinal cortex* - The entorhinal cortex is located in the **medial temporal lobe**, adjacent to the hippocampus. - It serves as a major input/output structure for the hippocampal formation and is not located on the medial occipital cortex where the calcarine sulcus is found.

Q: Identify the structure shown below. (Recent NEET Pattern 2019)

Fornix. ***Fornix*** - The arrow points to a C-shaped bundle of **nerve fibers** in the brain that acts as the primary efferent (output) pathway of the **hippocampus**, a crucial structure for memory. - It is located inferior to the corpus callosum and its position in the image is consistent with the anatomical location of the fornix. *Corpus callosum* - The corpus callosum is a large, **C-shaped nerve fiber bundle** located beneath the cerebral cortex in the longitudinal fissure, connecting the left and right cerebral hemispheres. - While visible in the image, the arrow specifically indicates the structure immediately beneath it, which is the fornix, not the corpus callosum itself. *Pineal gland* - The **pineal gland** is a small endocrine gland located in the epithalamus, near the center of the brain, behind the thalamus. - Its position is medial and inferior to the structure indicated by the arrow. *Splenium* - The **splenium** is the posterior, thicker part of the **corpus callosum**, forming its most caudal end. - The arrow points to a more anterior and inferior structure than the splenium. *Septum pellucidum* - The **septum pellucidum** is a thin, vertical membrane separating the anterior horns of the left and right lateral ventricles. - It is located superior and anterior to the fornix, positioned between the corpus callosum above and the fornix below, which is different from the structure indicated by the arrow.

Q: Identify the nerve marked with an arrow in the given section of cranial cavity.

Abducens. ***Abducens*** - The image shows the abducens nerve passing through **Dorello's canal** on its way to the **cavernous sinus**. - Its unique path makes it susceptible to injury in cases of increased intracranial pressure, leading to **lateral rectus palsy**. *Trochlear* - The trochlear nerve is the **smallest cranial nerve** and exits the brainstem dorsally, then wraps around to the ventral side. - It innervates the **superior oblique muscle** of the eye. *Trigeminal* - The trigeminal nerve is a large cranial nerve with **three main divisions** and is responsible for sensations in the face and motor functions like chewing. - It arises more laterally from the pons and is typically seen entering the **Meckel's cave**. *Oculomotor* - The oculomotor nerve emerges from the **midbrain** and controls most of the extrinsic eye muscles and pupillary constriction. - It is usually visible superior to the abducens nerve in the **cavernous sinus**. *Facial* - The facial nerve exits the brainstem at the **cerebellopontine angle** and enters the **internal acoustic meatus** with the vestibulocochlear nerve. - It controls muscles of **facial expression** and carries taste sensation from the anterior two-thirds of the tongue.

Q: A child is brought with fever and ear pain. On examination following findings are noted. The cranial nerve involved for ear pain is:

9th nerve. ***9th nerve*** - The **glossopharyngeal nerve (CN IX)** innervates the **nasopharynx, tonsils, soft palate, and Eustachian tube**, areas that can refer pain to the ear. - Infection or inflammation in these structures, such as a **pharyngitis** or **tonsillitis** (as suggested by the image showing exudative tonsils), can cause **referred otalgia** via CN IX. *5th nerve* - The **trigeminal nerve (CN V)** primarily supplies sensory innervation to the face, teeth, and anterior two-thirds of the tongue. - While it has a small branch (auriculotemporal) to the external ear, it is less commonly involved in referred ear pain associated with a pharyngeal infection compared to the glossopharyngeal nerve. *7th nerve* - The **facial nerve (CN VII)** is primarily a motor nerve for facial expression and taste sensation. - It carries some sensory fibers from the external auditory canal, but it is not a major pathway for referred ear pain from the pharynx. *10th nerve* - The **vagus nerve (CN X)** innervates a wide range of structures, including parts of the pharynx, larynx, and external ear canal (Arnold's nerve). - While it can be involved in referred otalgia, the **glossopharyngeal nerve (CN IX)** is more frequently associated with ear pain originating from the tonsillar and pharyngeal regions, especially in cases of infection. *12th nerve* - The **hypoglossal nerve (CN XII)** is a purely motor nerve that innervates the intrinsic and extrinsic muscles of the tongue. - It has no sensory function and does not contribute to ear pain or referred otalgia.

Q: A 4-day-old neonate under phototherapy in NICU. The child has shrill cry. All are true about the acute presentation of the disease except:

Athetosis. ***Athetosis*** - **Athetosis** refers to slow, writhing involuntary movements, which are typically a **chronic manifestation** of severe neurological damage, such as that caused by **kernicterus**, rather than an acute presentation. - Acute bilirubin encephalopathy primarily presents with signs of severe neurological distress but not typically with athetosis. - This is a **late sequela** of kernicterus, appearing weeks to months after the acute injury. *Seizures* - **Seizures** are a common acute manifestation of **acute bilirubin encephalopathy (kernicterus)** due to bilirubin toxicity in the brain, especially in the basal ganglia. - The **shrill cry** mentioned in the patient's presentation can be a precursor or an accompanying symptom of neurological irritation that can lead to seizures. *Opisthotonus* - **Opisthotonus** is a severe neurological sign characterized by **arching of the back and neck**, often due to severe spasm of the extensor muscles. - It is a classic **acute manifestation of kernicterus**, indicating significant bilirubin-induced damage to the central nervous system. *Retrocollis* - **Retrocollis** is a specific type of **dystonia** characterized by involuntary **backward deviation of the head and neck**. - This is an **acute neurological symptom** that can occur in severe cases of kernicterus as part of the overall extrapyramidal involvement. *Hypotonia* - **Hypotonia** (decreased muscle tone) is an **acute manifestation** of bilirubin encephalopathy. - It occurs during the early phase of acute kernicterus along with lethargy, poor feeding, and loss of the Moro reflex.

Q: At what age does maximum brain growth occur?

6 months. ***6 months*** - **Brain growth** is most rapid during the early postnatal period, with the brain reaching almost **50% of its adult size by 6 months of age**. - This period involves rapid **synaptogenesis** and myelination, crucial for early cognitive and motor development. *1 year* - While significant **brain growth** continues, the peak rate of increase in brain volume has typically passed by 1 year. - At this age, the brain has reached approximately **75% of its adult size**. *2 years* - By 2 years, the brain is about **80% of its adult size**, indicating ongoing but slower growth compared to the first year. - This period is more characterized by refinement of neural circuits rather than rapid volumetric expansion. *3 years* - At 3 years, the brain has attained around **90% of its adult size**, though important developmental changes continue. - The rate of **neural development** at this stage largely focuses on strengthening existing connections and pruning less used ones. *5 years* - By 5 years, the brain has reached approximately **90-95% of its adult size**, with growth significantly slower than in earlier years. - Development at this age focuses primarily on **synaptic pruning** and refinement of neural networks rather than volumetric growth.

Q: Arrange in sequence the structures involved in the direct pathway (1=Striatum, 2=GPi, 3=Thalamus, 4=Cortex output, 5=Cortex input):-

5,1,2,3,4. ***5,1,2,3,4*** - The direct pathway of the basal ganglia begins with the **cortex** (5) sending excitatory signals to the **striatum** (1). - The striatum then inhibits the **internal globus pallidus (GPi)** (2), which disinhibits the **thalamus** (3), leading to excitation of the **cortex** (4). - This is the correct sequence: **Cortex input → Striatum → GPi → Thalamus → Cortex output**. *1,3,4,2,5* - This sequence is incorrect as it starts with the striatum instead of cortical input. - The direct pathway does not begin with striatal activity; the cortex must first activate the striatum. *1,2,3,4,5* - This order is incorrect because it implies the pathway starts at the striatum rather than the cortex. - The cortex should be the starting point (5) and the ending point (4) of the motor loop. *5,4,2,3,1* - This sequence is incorrect as it places cortex output (4) before the striatum receives input. - This reverses the functional flow and does not follow the **disinhibitory mechanism** of the direct pathway. *5,1,3,2,4* - This sequence incorrectly places the thalamus (3) before the GPi (2). - In the direct pathway, the striatum must first inhibit the GPi before the thalamus can be disinhibited.

Q: A 2-year-old boy is brought to the physician because of progressive headaches, dizziness, and recurrent episodes of vomiting for 3 weeks. He has a history of surgical removal of a sac-like protuberance on his lower back soon after birth. Neurologic examination shows ataxia. Fundoscopy shows bilateral optic disk swelling. An MRI of the brain is shown. Which of the following is the most likely diagnosis?

Chiari II malformation. ***Chiari II malformation*** - History of **surgical removal of a sac-like protuberance on the lower back** (myelomeningocele) is nearly **100% associated with Chiari II malformation** - MRI shows **downward displacement of the cerebellar vermis and brainstem** into the foramen magnum, the pathognomonic finding - Symptoms of progressive **headaches, dizziness, vomiting, and ataxia** with **optic disk swelling** indicate increased intracranial pressure from associated hydrocephalus and brainstem compression *Dandy-Walker malformation* - Characterized by **cystic dilation of the fourth ventricle**, **agenesis or hypoplasia of the cerebellar vermis**, and **enlargement of the posterior fossa** - Can cause hydrocephalus and similar symptoms, but MRI does not show a large posterior fossa cyst - **History of myelomeningocele strongly points to Chiari II**, not Dandy-Walker *Medulloblastoma* - **Malignant cerebellar tumor** most common in children, would appear as a **discrete mass lesion** on MRI - Can cause increased intracranial pressure and ataxia, but MRI shows **structural malformation** rather than a tumor mass - Not associated with myelomeningocele history *Vestibular schwannoma* - **Benign tumor of the vestibular nerve** presenting as a mass in the **cerebellopontine angle** on MRI - Typically occurs in **adults** with hearing loss, tinnitus, and balance problems - Extremely rare in a 2-year-old and not seen on this MRI *Ependymoma* - **Tumor arising from ependymal cells** lining the ventricles, often in the fourth ventricle - Would present as a **distinct mass lesion** on MRI, not the structural malformation shown - Not associated with myelomeningocele history

Question 1

A histology slide from a surgical biopsy of the small intestine reveals tall columnar cells with a prominent brush border, interspersed with flask-shaped cells containing apical mucin granules, and occasional triangular cells wedged at the base of the crypts with eosinophilic granules. A separate population of undifferentiated cells is clustered at the base of the crypts. Based on this architecture, which cell type is responsible for the eosinophilic granules and what is its primary functional role?

Accepted Answer

Paneth cells; secretion of antimicrobial peptides including defensins and lysozyme

Answer

Enteroendocrine cells; secretion of cholecystokinin in response to luminal fat

Answer

Goblet cells; secretion of mucin to lubricate and protect the epithelial surface

Answer

Tuft cells; chemosensory detection of luminal parasites and initiation of type 2 immunity

Answer

M cells; transcytosis of luminal antigens to underlying Peyer patches

Question 2

Name the center shown as $X$ in the cut section of medulla which is responsible for control of respiration.

Accepted Answer

Pre-Botzinger Complex

Answer

Pneumotaxic centre

Answer

Nucleus Para-brachialis

Answer

Dorsal group of respiratory neurons

Answer

Ventral group of respiratory neurons

Question 3

The marked area in the image given below is associated with which part of brain cortex?

Accepted Answer

Striate cortex

Answer

Hippocampus

Answer

Dentate nucleus

Answer

Orbital cortex

Answer

Entorhinal cortex

Question 4

Identify the structure shown below. (Recent NEET Pattern 2019)

Accepted Answer

Fornix

Answer

Corpus callosum

Answer

Pineal gland

Answer

Splenium

Answer

Septum pellucidum

Question 5

Identify the nerve marked with an arrow in the given section of cranial cavity.

Accepted Answer

Abducens

Answer

Trochlear

Answer

Trigeminal

Answer

Oculomotor

Answer

Facial

Question 6

A child is brought with fever and ear pain. On examination following findings are noted. The cranial nerve involved for ear pain is:

Accepted Answer

9th nerve

Answer

5th nerve

Answer

7th nerve

Answer

10th nerve

Answer

12th nerve

Question 7

A 4-day-old neonate under phototherapy in NICU. The child has shrill cry. All are true about the acute presentation of the disease except:

Accepted Answer

Athetosis

Answer

Seizures

Answer

Opisthotonus

Answer

Retrocollis

Answer

Hypotonia

Question 8

At what age does maximum brain growth occur?

Accepted Answer

6 months

Answer

1 year

Answer

2 years

Answer

3 years

Answer

5 years

Question 9

Arrange in sequence the structures involved in the direct pathway (1=Striatum, 2=GPi, 3=Thalamus, 4=Cortex output, 5=Cortex input):-

Accepted Answer

5,1,2,3,4

Answer

1,3,4,2,5

Answer

1,2,3,4,5

Answer

5,4,2,3,1

Answer

5,1,3,2,4

Question 10

A 2-year-old boy is brought to the physician because of progressive headaches, dizziness, and recurrent episodes of vomiting for 3 weeks. He has a history of surgical removal of a sac-like protuberance on his lower back soon after birth. Neurologic examination shows ataxia. Fundoscopy shows bilateral optic disk swelling. An MRI of the brain is shown. Which of the following is the most likely diagnosis?

Accepted Answer

Chiari II malformation

Answer

Dandy-Walker malformation

Answer

Medulloblastoma

Answer

Vestibular schwannoma

Answer

Ependymoma

Neuroanatomy — MCQs

Neuroanatomy — MCQs

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