Anatomy
10 questionsLargest cranial nerve is:
The nasopharynx is primarily lined by which type of epithelium?
From which structure is the greater petrosal nerve formed?
The third ventricle is a cavity located in which part of the brain?
Oculomotor nucleus is located in -
Which of the following is pure sensory nerve?
The Great cerebral vein of Galen drains into which structure?
Superficial middle cerebral vein drains into -
Which artery is the major supply of the medial surface of the cerebral hemisphere?
Ligament which prevents the spleen from falling in left iliac fossa -
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 111: Largest cranial nerve is:
- A. Trochlear
- B. Trigeminal (Correct Answer)
- C. Oculomotor
- D. Vagus
Explanation: ***Trigeminal*** - The **trigeminal nerve (CN V)** is the largest cranial nerve, both in terms of its overall diameter and the number of fibers it contains. - It has three major divisions: **ophthalmic, maxillary, and mandibular**, providing extensive sensory innervation to the face and motor innervation to the muscles of mastication. *Trochlear* - The **trochlear nerve (CN IV)** is the smallest cranial nerve in terms of diameter and number of axons. - It primarily innervates a single muscle, the **superior oblique muscle** of the eye. *Oculomotor* - The **oculomotor nerve (CN III)** is responsible for innervating several extrinsic eye muscles and plays a role in pupil constriction. - While significant, it is not the largest cranial nerve. *Vagus* - The **vagus nerve (CN X)** has the longest anatomical course among all cranial nerves, extending into the abdomen, but it is not the largest in terms of overall size or fiber count. - It carries extensive **parasympathetic fibers** and has broad effects on visceral organs.
Question 112: The nasopharynx is primarily lined by which type of epithelium?
- A. Stratified squamous keratinized
- B. Ciliated columnar (Correct Answer)
- C. Cuboidal
- D. Stratified squamous nonkeratinized
Explanation: ***Ciliated columnar*** - The **nasopharynx** is lined by **pseudostratified ciliated columnar epithelium** with goblet cells, also known as respiratory epithelium [2]. - This specialized epithelium is crucial for **warming**, **humidifying**, and **filtering** inhaled air before it reaches the lungs [1]. *Stratified squamous nonkeratinized* - This type of epithelium is found in areas subject to **abrasion** and needing protection, such as the **oral cavity**, pharynx (oropharynx and laryngopharynx), and esophagus. - It is not primary in the nasopharynx, which requires ciliary action for particle removal. *Stratified squamous keratinized* - This robust epithelium is characteristic of areas that require significant **protection against friction** and **drying**, such as the **epidermis of the skin**. - It is not found in the nasopharynx due to its lack of flexibility and ciliary function. *Cuboidal* - **Cuboidal epithelium** is typically found in glands and kidney tubules, where its function includes **secretion** and **absorption**. - It lacks the specialized cilia and goblet cells necessary for the respiratory function of the nasopharynx [2].
Question 113: From which structure is the greater petrosal nerve formed?
- A. Geniculate ganglion (Correct Answer)
- B. Plexus around ICA
- C. Plexus around middle meningeal artery
- D. None of the options
Explanation: ***Geniculate ganglion*** - The **greater petrosal nerve** arises directly from the **geniculate ganglion** of the **facial nerve (cranial nerve VII)**. - This nerve carries **preganglionic parasympathetic fibers** destined for the lacrimal gland and mucous glands of the nose, palate, and pharynx, as well as **taste fibers** from the palate. *Plexus around ICA* - The **plexus around the internal carotid artery (ICA)** typically carries **postganglionic sympathetic fibers**, primarily for structures in the head, including the dilator pupillae muscle. - It does not give rise to the greater petrosal nerve, which is predominantly parasympathetic and sensory. *Plexus around middle meningeal artery* - The **plexus around the middle meningeal artery** consists mainly of **sympathetic fibers** that supply the artery itself and surrounding structures. - It has no direct connection or contribution to the formation of the greater petrosal nerve. *None of the options* - This option is incorrect because the **greater petrosal nerve** does indeed arise from the **geniculate ganglion**.
Question 114: The third ventricle is a cavity located in which part of the brain?
- A. Mesencephalon
- B. Rhombencephalon
- C. Diencephalon (Correct Answer)
- D. Telencephalon
Explanation: ***Diencephalon*** - The **third ventricle** is a narrow, median cavity situated within the **diencephalon** of the brain. - It connects the lateral ventricles via the **interventricular foramen (of Monro)** and with the fourth ventricle via the **cerebral aqueduct (of Sylvius)** [2]. *Mesencephalon* - The **mesencephalon (midbrain)** contains the **cerebral aqueduct**, but not the third ventricle itself [1]. - It is located superior to the pons and inferior to the diencephalon. *Rhombencephalon* - The **rhombencephalon (hindbrain)** contains the **fourth ventricle**, which is situated posterior to the pons and medulla oblongata [2]. - It develops into the pons, cerebellum, and medulla oblongata. *Telencephalon* - The **telencephalon (cerebrum)** contains the **lateral ventricles**, which are paired cavities, one in each cerebral hemisphere [2]. - The telencephalon is the most anterior part of the brain and develops into the cerebral cortex, basal ganglia, and limbic system.
Question 115: Oculomotor nucleus is located in -
- A. Forebrain
- B. Midbrain (Correct Answer)
- C. Pons
- D. Medulla
Explanation: ***Midbrain*** - The **oculomotor nucleus** (cranial nerve III) and the Edinger-Westphal nucleus (parasympathetic component) are both located in the **ventral gray matter** near the cerebral aqueduct in the **midbrain** [1]. - This position allows the oculomotor nerve to exit from the interpeduncular fossa of the midbrain [1]. *Forebrain* - The **forebrain** primarily contains structures like the cerebral hemispheres, thalamus, and hypothalamus, which are involved in higher cognitive functions and sensory processing. - No cranial nerve nuclei are located within the forebrain itself; they are largely concentrated in the brainstem. *Pons* - The **pons** contains nuclei for cranial nerves V (trigeminal), VI (abducens), VII (facial), and VIII (vestibulocochlear), but not the oculomotor nucleus. - It is located inferior to the midbrain and superior to the medulla. *Medulla* - The **medulla oblongata** houses nuclei for cranial nerves IX (glossopharyngeal), X (vagus), XI (accessory), and XII (hypoglossal). - It is the most caudal part of the brainstem, inferior to the pons, and is not where the oculomotor nucleus is found.
Question 116: Which of the following is pure sensory nerve?
- A. Trigeminal
- B. Abducent
- C. Trochlear
- D. Olfactory (Correct Answer)
Explanation: ***Olfactory*** - The **olfactory nerve (Cranial Nerve I)** is exclusively responsible for the sense of **smell**, making it a pure **sensory nerve** [1]. - It transmits impulses from the **olfactory receptors** in the nasal cavity to the brain. *Trigeminal* - The **trigeminal nerve (Cranial Nerve V)** is a **mixed nerve**. - It has both **sensory functions** (face sensation) and **motor functions** (mastication). *Abducent* - The **abducent nerve (Cranial Nerve VI)** is a **motor nerve**. - It innervates the **lateral rectus muscle**, responsible for moving the eye laterally. *Trochlear* - The **trochlear nerve (Cranial Nerve IV)** is primarily a **motor nerve**. - It innervates the **superior oblique muscle**, which depresses and intorts the eyeball.
Question 117: The Great cerebral vein of Galen drains into which structure?
- A. Cavernous sinus
- B. Basal vein of Rosenthal
- C. Internal cerebral vein
- D. Straight sinus (Correct Answer)
Explanation: ***Straight sinus*** - The **Great cerebral vein of Galen** is a major venous channel that collects blood from the deep cerebral veins, including the internal cerebral veins. - It empties directly into the **straight sinus**, which then joins the confluence of sinuses. *Cavernous sinus* - The **cavernous sinus** drains blood from the orbit, face, and temporal lobe, and it receives input from superficial cerebral veins, not the deep system of Galen. - It is located on either side of the **sella turcica** and is distinct from the drainage pathway of the Great cerebral vein. *Basal vein of Rosenthal* - The **basal vein of Rosenthal** is a tributary that drains into the Great cerebral vein of Galen, not a structure that Galen drains into. - It courses around the midbrain and receives blood from various deep structures, eventually contributing to the formation of the Great cerebral vein. *Internal cerebral vein* - The **internal cerebral veins** are tributaries that merge to form the Great cerebral vein of Galen; therefore, Galen does not drain into them. - These veins run within the tela choroidea of the third ventricle and collect blood from the thalamus, basal ganglia, and internal capsule.
Question 118: Superficial middle cerebral vein drains into -
- A. Internal cerebral vein
- B. Cavernous sinus (Correct Answer)
- C. Great cerebral vein of Galen
- D. Straight sinus
Explanation: **Cavernous sinus** - The **superficial middle cerebral vein** runs along the **lateral sulcus** and is a major drainage pathway, typically emptying into the **cavernous sinus**. - Its drainage into the **cavernous sinus** then allows blood to eventually reach the superior and inferior petrosal sinuses [1]. *Internal cerebral vein* - This vein is part of the **deep venous system** of the brain [1] and primarily drains structures like the **basal ganglia** and **thalamus**. - It does not receive direct drainage from the **superficial middle cerebral vein**. *Great cerebral vein of Galen* - The **great cerebral vein of Galen** is formed by the union of the **internal cerebral veins** and is a major collector of **deep venous blood**. - It drains into the **straight sinus** and is not the primary drainage site for the superficial middle cerebral vein. *Straight sinus* - The **straight sinus** is a large dural venous sinus that receives blood from the **great cerebral vein of Galen** and the **inferior sagittal sinus**. - It primarily drains deeper structures of the brain and does not directly receive the **superficial middle cerebral vein** [1].
Question 119: Which artery is the major supply of the medial surface of the cerebral hemisphere?
- A. Anterior cerebral artery (Correct Answer)
- B. Posterior cerebral artery
- C. Middle cerebral artery
- D. Posterior inferior cerebellar artery
Explanation: ***Anterior cerebral artery*** - The **anterior cerebral artery (ACA)** is a primary branch of the internal carotid artery and is responsible for supplying blood to the **medial surface** of the frontal and parietal lobes of the cerebral hemispheres [1]. - It also supplies the **corpus callosum**, the superior aspect of the frontal and parietal lobes, and parts of the basal ganglia [1]. *Posterior cerebral artery* - The **posterior cerebral artery (PCA)** primarily supplies the **occipital lobe** and the inferior part of the **temporal lobe** [1]. - It also provides blood to parts of the midbrain and the **thalamus** [1]. *Middle cerebral artery* - The **middle cerebral artery (MCA)** is the largest cerebral artery and supplies most of the **lateral surface** of the cerebral hemispheres [1]. - It is crucial for the blood supply to the **motor and sensory cortices** for the face and upper limb, as well as language areas (Broca's and Wernicke's). *Posterior inferior cerebellar artery* - The **posterior inferior cerebellar artery (PICA)** is a branch of the **vertebral artery** and exclusively supplies the **cerebellum** and the lateral medulla. - It is not involved in the blood supply to the cerebral hemispheres.
Question 120: Ligament which prevents the spleen from falling in left iliac fossa -
- A. Phrenicocolic ligament (Correct Answer)
- B. Lienorenal ligament
- C. Upper pole of right kidney
- D. Sigmoid colon
Explanation: ***Phrenicocolic ligament*** - The **phrenicocolic ligament** is a fold of peritoneum that extends from the left colic flexure to the diaphragm, under the spleen. - It forms a shelf that **supports the spleen** and prevents it from descending into the left iliac fossa. *Lienorenal ligament* - The **lienorenal (splenorenal) ligament** connects the hilum of the spleen to the posterior abdominal wall (specifically over the left kidney) [1]. - While it helps to anchor the spleen, its primary role is not preventing caudal displacement, but rather containing the **splenic artery and vein** and the tail of the pancreas [1]. *Upper pole of right kidney* - The **right kidney** is located on the opposite side of the abdominal cavity from the spleen. - It plays no role in supporting the spleen or preventing its descent. *Sigmoid colon* - The **sigmoid colon** is a part of the large intestine located in the left lower quadrant of the abdomen and pelvis. - It is situated far below the spleen and has no direct anatomical connection or supporting role for the spleen.