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?
Which nucleus is not seen in floor of the 4th ventricle -
Which tract is responsible for the ventral tegmental decussation in the cerebral peduncle?
Lining epithelium of vagina is
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 81: 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 82: 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 83: 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 84: 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 85: 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 86: 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 87: 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 88: Which nucleus is not seen in floor of the 4th ventricle -
- A. Dorsal vagal nucleus
- B. Hypoglossal nucleus
- C. Abducens nucleus
- D. Facial nucleus (Correct Answer)
Explanation: Facial nucleus - The facial nucleus is located in the pontine tegmentum, anterior and ventrolateral to the abducens nucleus, and its fibers loop around the abducens nucleus forming the facial colliculus within the floor of the fourth ventricle, but the nucleus itself is not directly in the floor. - The nucleus's motor neurons originate deeper within the brainstem, not superficially in the floor. Abducens nucleus - The abducens nucleus is directly located in the floor of the fourth ventricle, beneath the facial colliculus. - Its neurons are responsible for innervating the lateral rectus muscle of the eye. Dorsal vagal nucleus - The dorsal vagal nucleus is situated in the floor of the fourth ventricle in the medulla, specifically in the vagal trigone. - It is responsible for the parasympathetic innervation of organs below the neck. Hypoglossal nucleus - The hypoglossal nucleus is located in the floor of the fourth ventricle, forming the hypoglossal trigone in the medulla. - It contains motor neurons that innervate the intrinsic and extrinsic muscles of the tongue.
Question 89: Which tract is responsible for the ventral tegmental decussation in the cerebral peduncle?
- A. Tectospinal tract
- B. Vestibulospinal tract
- C. Rubrospinal tract (Correct Answer)
- D. Tectobulbar tract
Explanation: The rubrospinal tract originates in the red nucleus and decussates in the ventral tegmental decussation at the level of the midbrain, before descending to the spinal cord. This decussation is the characteristic feature that distinguishes it from other descending tracts. It primarily modulates flexor muscle tone and fine motor control of distal limb muscles. The tectospinal tract originates in the superior colliculus and decussates immediately as the dorsal tegmental decussation, involved in coordinating head and eye movements in response to stimuli. The vestibulospinal tract originates in the vestibular nuclei and descends ipsilaterally and contralaterally [1], but it does not form a distinct ventral tegmental decussation in the cerebral peduncle. It is crucial for maintaining posture and balance by influencing extensor muscles [1]. The tectobulbar tract arises from the superior colliculus and projects to cranial nerve nuclei, but it does not undergo the specific ventral tegmental decussation.
Question 90: Lining epithelium of vagina is
- A. Squamous epithelium (Correct Answer)
- B. Columnar epithelium
- C. Transitional epithelium
- D. Secretory epithelium
Explanation: Squamous epithelium * The vagina is lined by stratified squamous non-keratinized epithelium [1], providing a protective barrier against friction and pathogens. * This type of epithelium is well-suited for areas subject to significant mechanical stress, such as during intercourse and childbirth. Columnar epithelium * Columnar epithelium [2] is typically found in areas specialized for secretion and absorption, such as the gastrointestinal tract and glandular linings. * It would not offer the necessary protective qualities for the vaginal environment. Transitional epithelium * Transitional epithelium is a specialized stratified epithelium found in the urinary tract, capable of stretching and distending. * It is not found in the vagina, which requires a more robust, friction-resistant lining. Secretory epithelium * While the cervix has secretory glands, the lining of the vagina itself is not primarily secretory. * The primary role of the vaginal lining is protection, not secretion, and its cells do not typically produce a large amount of substances.