Anatomy
3 questionsAll are parts of anterior segment of eye except?
The junction between Retina & Ciliary body is?
Which are the second order neurons in the optic pathway?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 1011: All are parts of anterior segment of eye except?
- A. Lens
- B. Cornea
- C. Aqueous humor
- D. Vitreous (Correct Answer)
Explanation: ***Vitreous*** - The **vitreous humor**, or simply vitreous, is a transparent, gel-like substance that fills the space posterior to the lens and anterior to the retina, making it part of the **posterior segment** of the eye [3]. - Its main function is to maintain the shape of the eye and keep the retina in place. *Lens* - The **lens** is a transparent, biconvex structure located behind the iris and in front of the vitreous, making it a key component of the **anterior segment** [2]. - It works to focus light onto the retina, changing shape to alter the focal length of the eye. *Cornea* - The **cornea** is the transparent, outermost layer of the eye that covers the iris, pupil, and anterior chamber, clearly positioning it within the **anterior segment** [2]. - It plays a crucial role in focusing light into the eye. *Aqueous humor* - The **aqueous humor** is a clear, watery fluid located in the space between the cornea and the lens (the anterior and posterior chambers), which is definitively part of the **anterior segment** [1]. - It nourishes the cornea and lens and maintains intraocular pressure.
Question 1012: The junction between Retina & Ciliary body is?
- A. Equator
- B. Pars plicata
- C. Pars plana
- D. Ora serrata (Correct Answer)
Explanation: ***Ora serrata*** - The **ora serrata** represents the **anterior-most jagged edge** of the retina where the sensory retina terminates. [1] - It marks the transition point where the neural retina becomes the **non-photoreceptive ciliary body epithelium**. *Equator* - The **equator** is the imaginary line circling the globe of the eye, approximately equidistant from the anterior and posterior poles. - It is a landmark on the retina itself, indicating the approximate middle of the retina, and not its junction with the ciliary body. *Pars plicata* - The **pars plicata** is the anterior, folded portion of the **ciliary body** that produces aqueous humor. - While part of the ciliary body, it is anterior to the junction with the retina and not the junction itself. *Pars plana* - The **pars plana** is the posterior, relatively flat portion of the **ciliary body**, located between the ora serrata and the pars plicata. - It is a part of the ciliary body immediately adjacent to the ora serrata, but the ora serrata itself is the definitive junction.
Question 1013: Which are the second order neurons in the optic pathway?
- A. Bipolar cells (Correct Answer)
- B. Ganglionic cells
- C. Cells of lateral geniculate body
- D. Astrocytes
Explanation: ***Bipolar cells*** - **Photoreceptors** (rods and cones) are first-order neurons, sensing light. [1] - **Bipolar cells** receive input from photoreceptors and transmit signals to retinal ganglion cells, acting as second-order neurons. [1] *Ganglionic cells* - **Ganglion cells** are third-order neurons in the visual pathway. [1] - Their axons form the **optic nerve**, which carries visual information to the brain. [2] *Cells of lateral geniculate body* - The **lateral geniculate nucleus (LGN)** of the thalamus contains fourth-order neurons. [1] - These cells project to the primary visual cortex. [2] *Astrocytes* - **Astrocytes** are a type of glial cell that provides support and protection to neurons in the central nervous system. - They are **not directly involved** in the transmission of visual information in the optic pathway.
ENT
1 questionsWhich of the following statements about laryngeal tuberculosis (TB) is true?
NEET-PG 2013 - ENT NEET-PG Practice Questions and MCQs
Question 1011: Which of the following statements about laryngeal tuberculosis (TB) is true?
- A. It commonly involves the posterior 1/3 of the vocal cord.
- B. It is more common in females.
- C. It is a common form of tuberculosis.
- D. It presents with a mouse-nibbled appearance of the vocal cord. (Correct Answer)
Explanation: ***It presents with a mouse-nibbled appearance of the vocal cord.*** - The appearance of a **mouse-nibbled vocal cord** is a classic and pathognomonic description of the irregular, ulcerated, and often edematous lesions seen in laryngeal tuberculosis. - This characteristic finding is due to the granulomatous inflammation and tissue destruction caused by *Mycobacterium tuberculosis* in the larynx. *It commonly involves the posterior 1/3 of the vocal cord.* - Laryngeal tuberculosis typically affects the **anterior two-thirds of the vocal cord**, rather than the posterior third, and often involves the arytenoids and epiglottis. - The involvement pattern can be variable, but posterior involvement is less common than mid-cord or anterior involvement. *It is more common in females.* - Laryngeal tuberculosis is generally **more common in males** than in females, with a male-to-female ratio often reported to be around 2-3:1. - This higher prevalence in males may be attributed to a combination of factors including occupational exposure and lifestyle choices. *It is a common form of tuberculosis.* - Laryngeal tuberculosis is considered a **rare form of extrapulmonary TB**, accounting for a small percentage of all TB cases. - Pulmonary tuberculosis is much more common, and laryngeal involvement is often secondary to active pulmonary disease, occurring via direct spread of infected sputum.
Internal Medicine
1 questionsIn head injury, unilateral dilatation of the pupil is seen due to?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 1011: In head injury, unilateral dilatation of the pupil is seen due to?
- A. Ophthalmic N. compression
- B. Trigeminal N. compression
- C. Oculomotor nerve compression (Correct Answer)
- D. None of the options
Explanation: Oculomotor nerve compression - Unilateral pupillary dilation, often referred to as a **blown pupil**, is a classic sign of **oculomotor nerve (CN III) compression** due to increased intracranial pressure, typically from a **herniating uncus** [1]. - The parasympathetic fibers responsible for pupillary constriction run on the superficial aspect of the oculomotor nerve and are thus vulnerable to extrinsic compression [1], [2]. *Ophthalmic N. compression* - The **ophthalmic nerve (CN V1)** is a sensory nerve responsible for sensation to the forehead, scalp, upper eyelid, and cornea, not pupillary control. - Compression of this nerve would cause **sensory deficits** in its distribution and potentially abolish the **corneal reflex**, but not pupillary dilation. *Trigeminal N. compression* - The **trigeminal nerve (CN V)** is primarily responsible for sensation to the face and motor control of the muscles of mastication. - Compression would lead to **facial numbness or pain** and **weakness in chewing**, with no direct impact on pupillary size. *None of the options* - This option is incorrect because oculomotor nerve compression is a well-established cause of unilateral pupillary dilation in head injuries [1].
Ophthalmology
5 questionsWhich of the following conditions is least likely to cause proptosis?
Normal level of visual acuity is attained at which age
What is the normal aqueous production rate in the human eye?
Maximum correction of myopia can be done by?
Which Goldmann type is considered the standard in perimetry?
NEET-PG 2013 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 1011: Which of the following conditions is least likely to cause proptosis?
- A. Sarcoidosis
- B. Myxoedema (Correct Answer)
- C. Grave's disease
- D. Pituitary adenoma
Explanation: ***Myxoedema*** - **Myxoedema** is associated with severe **hypothyroidism** and is characterized by non-pitting edema due to the accumulation of **glycosaminoglycans** in tissues. - While it can cause facial puffiness, it is **least likely** to cause **proptosis** as there is no direct mechanism for an increase in orbital contents to push the eye forward. *Grave's disease* - **Grave's disease** is the most common cause of **proptosis** due to **immune-mediated inflammation** and accumulation of **glycosaminoglycans** and fat in the orbital tissues, leading to expansion. - This condition specifically affects the **extraocular muscles** and fat, causing bulging of the eyes. *Sarcoidosis* - **Orbital sarcoidosis** can cause **proptosis** due to the formation of **granulomas** within the orbit, leading to mass effect and inflammation. - It can affect any part of the eye and orbit, leading to varied clinical presentations including axial or non-axial globe displacement. *Pituitary adenoma* - A **pituitary adenoma** itself does not directly cause proptosis as it is located in the **sella turcica**, posterior to the orbits. - However, **large adenomas** can cause proptosis indirectly if they invade the **cavernous sinus** and obstruct venous return from the orbit, or if they are associated with **acromegaly**, which can lead to bony overgrowth of the orbital structures and surrounding tissues.
Question 1012: Normal level of visual acuity is attained at which age
- A. 6 months
- B. 1 year
- C. 3 years
- D. 6 years (Correct Answer)
Explanation: ***6 years*** - **Normal adult visual acuity (20/20 or 6/6)** is typically achieved around the age of **6 years** as the visual system fully matures. - This age allows for the complete development of **foveal vision** and **binocular functions**. *6 months* - At 6 months of age, an infant's visual acuity is still developing and is typically around **20/200 to 20/400**. - While significant visual development occurs by this age, including **face recognition and tracking objects**, it is not yet at adult levels. *1 year* - By one year, visual acuity improves to approximately **20/50 to 20/100**. - Infants at this age are able to **distinguish fine details** and have improved **depth perception**, but full maturity is still some years away. *3 years* - At 3 years of age, visual acuity is generally around **20/30 to 20/40**. - Children at this stage are able to perform **visual tasks** like drawing and recognizing letters, but subtle refinements are still ongoing.
Question 1013: What is the normal aqueous production rate in the human eye?
- A. 2 µl/min (Correct Answer)
- B. 2 ml/min
- C. 5 ml/min
- D. 5 µl/min
Explanation: ***2 µl/min*** - The ciliary body in the human eye continuously produces **aqueous humor** at a typical rate of approximately **2.0-3.0 µl/min**. - This rate is crucial for maintaining **intraocular pressure (IOP)** and providing nutrients to avascular eye structures like the **cornea** and **lens**. - This translates to approximately **3-4 ml per day** of aqueous humor production. *2 ml/min* - This rate is significantly **higher** than the actual production of aqueous humor, which is measured in microliters per minute. - Such a high production rate would lead to a rapid and severe increase in **intraocular pressure**, causing damage to the eye. *5 ml/min* - This value is an **excessively high** rate of fluid production and is not physiologically correct for aqueous humor. - It would result in unsustainable and damaging **intraocular pressure** levels. *5 µl/min* - While closer to the correct order of magnitude, **5 µl/min** is generally considered to be at the higher end or slightly above the average physiological range for aqueous humor production. - Most sources cite the normal range as being between **2-3 µl/min**.
Question 1014: Maximum correction of myopia can be done by?
- A. Radial keratotomy
- B. LASIK (Correct Answer)
- C. Photorefractive keratectomy
- D. Orthokeratology
Explanation: ***LASIK*** - **LASIK (Laser-Assisted In Situ Keratomileusis)** allows for significant correction of high myopia by reshaping the cornea with an excimer laser. - It involves creating a **corneal flap** and then ablating tissue underneath, offering precise and stable vision correction for a wide range of refractive errors. - Among the given corneal refractive procedures, LASIK can correct myopia up to **-10 to -12 D**. *Radial keratotomy* - **Radial keratotomy (RK)** involves making radial incisions in the cornea to flatten it, primarily used for low to moderate myopia (up to -3 to -4 D). - It has a higher risk of **unpredictable outcomes**, induced astigmatism, and glare compared to modern laser procedures. *Photorefractive keratectomy* - **Photorefractive keratectomy (PRK)** involves direct ablation of the corneal surface without creating a flap, which is suitable for moderate myopia (up to -8 to -10 D). - While effective, PRK typically has a **longer recovery period** and more post-operative pain than LASIK. *Orthokeratology* - **Orthokeratology (Ortho-K)** uses specially designed rigid contact lenses worn overnight to temporarily reshape the cornea and correct myopia. - The effect is **temporary**, requiring continuous lens wear to maintain vision correction, and is generally limited to low to moderate myopia (up to -4 to -6 D).
Question 1015: Which Goldmann type is considered the standard in perimetry?
- A. Goldmann type I (small stimulus size)
- B. Goldmann type II (medium-small stimulus size)
- C. Goldmann type IV (large stimulus size)
- D. Goldmann type III (commonly used stimulus size) (Correct Answer)
Explanation: ***Goldmann type III (commonly used stimulus size)*** - This stimulus size is the **international standard** for kinetic perimetry and ensures comparability of visual field charts worldwide. - It provides a balance between **sensitivity** and minimizing the effects of **pupil size** and other ocular factors. *Goldmann type I (small stimulus size)* - While very small, this stimulus type is **not the standard** for general perimetry. - It is sometimes used for detecting **subtle defects** or for patients with very good visual acuity, but its small size can make it harder to detect. *Goldmann type II (medium-small stimulus size)* - This stimulus size is **smaller than the standard** and is not universally adopted for perimetry. - It offers slightly more sensitivity than the standard but can be more affected by **refractive errors** or media opacities. *Goldmann type IV (large stimulus size)* - This stimulus is **much larger than the standard** and is typically used for detecting **gross defects** or in patients with severely impaired vision. - Its large size makes it **less sensitive** to smaller visual field abnormalities.