Anatomy
2 questionsThe zonules suspending the lens are attached to the?
Lens is attached to ciliary body via?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 951: The zonules suspending the lens are attached to the?
- A. Root of iris
- B. Ciliary body (Correct Answer)
- C. Anterior vitreous
- D. Limbus
Explanation: ***Ciliary body*** - The **suspensory ligaments of the lens**, also known as zonules of Zinn, connect the **lens capsule** to the **ciliary body**. - These zonules play a crucial role in **accommodation** by transmitting forces from the ciliary muscle to alter the shape of the lens. *Root of iris* - The **root of the iris** attaches the iris to the ciliary body but does not directly connect to the lens zonules. - The iris primarily controls the **pupil size** and light entry, while the zonules are involved in lens suspension and focusing. *Anterior vitreous* - The **anterior vitreous** is the part of the vitreous humor located in front of the lens. - While it is in close proximity to the lens, the zonules do not directly attach to the vitreous but rather to the ciliary body. *Limbus* - The **limbus** is the transitional zone between the cornea and the sclera, the white outer layer of the eye. - It is an important anatomical landmark for eye surgery and drainage of aqueous humor, but it has no direct role in suspending the lens.
Question 952: Lens is attached to ciliary body via?
- A. Limbus
- B. Vitreous Humour
- C. Root of iris
- D. Zonular fibers (Correct Answer)
Explanation: ***Zonular fibers*** - The **suspensory ligaments** of the lens, known as zonular fibers (or **Zonules of Zinn**), connect the lens capsule to the ciliary body. - These fibers play a crucial role in **accommodation** by transmitting the tension from the ciliary muscle to the lens, causing it to change shape [2]. *Limbus* - The **limbus** is the junction between the cornea and the sclera, serving as a transitional zone [3]. - It does not directly attach the lens to the ciliary body but is an important anatomical landmark for eye surgery. *Vitreous Humour* - The **vitreous humor** is the clear, gel-like substance that fills the space between the lens and the retina [4]. - It maintains the shape of the eye and holds the retina in place, but it does not provide structural attachment for the lens. *Root of iris* - The **root of the iris** is the outermost part of the iris where it attaches to the ciliary body. - While it is adjacent to the ciliary body, it is the iris structure itself and does not serve to attach the lens [1].
Internal Medicine
4 questionsWhich of the following symptoms is least likely to be associated with hyponatremia?
A patient involved in an accident presents with unconsciousness. Upon physical examination, there is unilateral pupillary dilatation. What is the most likely cause of this finding?
Gaisbock syndrome is known as:
Hutchinson's Triad is specifically associated with which type of syphilis?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 951: Which of the following symptoms is least likely to be associated with hyponatremia?
- A. anorexia
- B. Drowsiness
- C. Convulsions
- D. Myalgia (Correct Answer)
Explanation: Myalgia - While muscle cramps can occur with electrolyte imbalances, generalized myalgia (muscle pain) is not a typical or primary symptom of hyponatremia. - Hyponatremia primarily affects neurological function due to osmotic shifts in the brain. anorexia - Anorexia (loss of appetite) is a common, non-specific symptom of many metabolic disturbances, including hyponatremia, and often accompanies nausea and vomiting. - It arises from the general malaise and gastrointestinal upset associated with the condition. Convulsions - Convulsions are a severe neurological symptom of acute and profound hyponatremia, resulting from cerebral edema and increased intracranial pressure [1]. - This occurs when the brain swells due to the osmotic shift of water into brain cells. Drowsiness - Drowsiness is a frequent neurological manifestation of hyponatremia, indicative of altered mental status [1]. - It reflects impaired brain function due to the osmotic disturbances and potential cerebral edema [1].
Question 952: A patient involved in an accident presents with unconsciousness. Upon physical examination, there is unilateral pupillary dilatation. What is the most likely cause of this finding?
- A. Uncal herniation (Correct Answer)
- B. Tonsillar herniation
- C. Cingulate herniation
- D. Transcalvarial herniation
Explanation: ***Uncal herniation*** - **Uncal herniation** compresses the **ipsilateral oculomotor nerve (CN III)**, leading to **pupillary dilation** due to predominant parasympathetic fiber damage [1], [2]. - This condition occurs when the **medial temporal lobe (uncus)** is forced over the tentorial notch, often as a result of a **supratentorial mass effect** [2]. *Tonsillar herniation* - **Tonsillar herniation** is the downward displacement of the **cerebellar tonsils** through the **foramen magnum** [1], [2]. - This compression primarily affects the **brainstem** and **cardiorespiratory centers**, causing **respiratory arrest** or **cardiac dysfunction**, not direct pupillary dilation [1]. *Cingulate herniation* - **Cingulate herniation** involves the displacement of the **cingulate gyrus** under the **falx cerebri**. - While it can lead to **hydrocephalus** and **cognitive changes**, it does not directly cause **unilateral pupillary dilation**. *Transcalvarial herniation* - **Transcalvarial herniation** occurs when **brain tissue** extends through a **skull defect** (e.g., following a craniectomy or skull fracture). - This type of herniation is typically visible externally and does not inherently cause **unilateral pupillary dilation** through direct nerve compression.
Question 953: Gaisbock syndrome is known as:
- A. Primary Familial Polycythemia
- B. High Altitude Erythrocytosis
- C. Spurious Polycythemia (Correct Answer)
- D. Polycythemia Vera
Explanation: ***Spurious Polycythemia*** - Gaisbock syndrome is characterized by an increase in **red blood cells** due to **dehydration** and is a form of **spurious or relative polycythemia** [1]. - It typically occurs in individuals with **high hematocrit levels** without true pathological erythrocytosis [1]. *High Altitude Erythrocytosis* - This condition is caused by **hypoxia** at high altitudes leading to increased **erythropoietin**, resulting in genuine **erythrocytosis** [2]. - Unlike Gaisbock syndrome, it reflects a true physiological response to reduced oxygen levels [2]. *Polycythemia Vera* - Polycythemia vera is a **myeloproliferative disorder** characterized by increased red blood cell mass due to intrinsic bone marrow changes. - It entails elevated **erythropoietin** levels and features such as **splenomegaly** and other cytogenetic changes, which are not present in Gaisbock syndrome [1][3]. *Primary Familial Polycythemia* - This hereditary condition results in increased red blood cells due to genetic mutations leading to overproduction of erythrocytes. - It is distinct from Gaisbock syndrome as it typically manifests from genetic predisposition rather than environmental factors such as dehydration.
Question 954: Hutchinson's Triad is specifically associated with which type of syphilis?
- A. Tertiary syphilis
- B. Primary syphilis
- C. Congenital Syphilis (Correct Answer)
- D. Secondary Syphilis
Explanation: ***Congenital Syphilis*** - **Hutchinson's Triad** is a classic constellation of symptoms specific to **congenital syphilis**, reflecting the long-term effects of *in utero* infection [1]. - The triad includes **Hutchinson's teeth** (notched incisors), **interstitial keratitis** (corneal inflammation), and **sensorineural hearing loss**. *Tertiary syphilis* - This stage is characterized by **gummas**, **cardiovascular syphilis** (e.g., aortitis), and **neurosyphilis**, but not Hutchinson's triad [1]. - These manifestations develop years after initial infection in adults. *Primary syphilis* - The primary stage is marked by the appearance of a **painless chancre** at the site of infection [1]. - It does not involve the systemic, long-term complications seen in congenital syphilis. *Secondary Syphilis* - This stage typically presents with a **diffuse maculopapular rash**, **lymphadenopathy**, and sometimes **condylomata lata** [1]. - These are acute systemic symptoms, distinct from the developmental abnormalities of Hutchinson's triad.
Obstetrics and Gynecology
1 questionsHydrocephalus is best detected antenatally by :
NEET-PG 2015 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 951: Hydrocephalus is best detected antenatally by :
- A. X-ray abdomen
- B. Amniocentesis
- C. Clinical examination
- D. Ultrasonography (Correct Answer)
Explanation: ***Ultrasonography*** - **Antenatal ultrasonography** is the primary and most effective method for detecting fetal hydrocephalus. - It allows direct visualization of **ventricular dilation**, the key diagnostic finding in hydrocephalus (lateral ventricles >10mm at atrium level). - USG is **safe, non-invasive**, and can be performed repeatedly without radiation exposure. - It also helps identify associated anomalies and determine the cause of hydrocephalus. *X-ray abdomen* - **X-rays** expose the fetus to **ionizing radiation**, posing risks and violating ALARA (As Low As Reasonably Achievable) principles. - They provide limited detail of **soft tissue structures** like brain ventricles, making them unsuitable for diagnosing hydrocephalus. - X-rays are not used for antenatal diagnosis of fetal brain abnormalities. *Amniocentesis* - **Amniocentesis** is primarily used for **chromosomal analysis** and genetic testing, not for direct visualization of brain anomalies. - While some genetic conditions can lead to hydrocephalus, amniocentesis doesn't directly detect the hydrocephalus itself. - It cannot visualize structural fetal abnormalities. *Clinical examination* - **Antenatal clinical examination** of the mother cannot directly assess fetal brain abnormalities. - It may suggest fetal issues if there is an abnormally large uterine size or polyhydramnios, but it **lacks the specificity and sensitivity** to diagnose hydrocephalus. - Clinical examination alone is inadequate for detecting structural fetal anomalies.
Ophthalmology
3 questionsWhere is the intraocular lens placed during cataract surgery?
Non foldable lens is made of?
Rigid gas permeable (RGP) lenses are made from which of the following combinations of materials?
NEET-PG 2015 - Ophthalmology NEET-PG Practice Questions and MCQs
Question 951: Where is the intraocular lens placed during cataract surgery?
- A. Surface of iris
- B. Capsular bag (Correct Answer)
- C. Around the limbus
- D. Over the face of vitreous
Explanation: ***Capsular bag*** - The **capsular bag** is the natural anatomical space where the human crystalline lens resides and is the ideal location for an intraocular lens (IOL) to mimic the natural lens's position and function. - Placing the IOL in the capsular bag provides **optimal stability**, centration, and reduces the risk of complications such as glare or secondary glaucoma. *Surface of iris* - Placing an IOL on the surface of the iris (**iris-fixated IOL**) is a less common surgical approach, typically reserved for cases where capsular support is absent or insufficient. - This position can lead to potential complications including **iris chafing**, pigment dispersion, and increased risk of uveitis or secondary glaucoma. *Over the face of vitreous* - Placing an IOL over the face of the vitreous typically occurs in cases of **capsular rupture** with inadequate posterior capsule support, requiring anterior vitrectomy and alternative IOL fixation. - This position is less stable and carries a higher risk of **vitreous prolapse**, retinal detachment, and cystoid macular edema compared to capsular bag placement. *Around the limbus* - The limbus is the **junction between the cornea and sclera** and is an entirely incorrect location for an intraocular lens implant. - An IOL around the limbus would be outside the globe and would serve no optical purpose within the eye, leading to **severe visual impairment** and potentially structural damage.
Question 952: Non foldable lens is made of?
- A. Acrylic
- B. PMMA (Correct Answer)
- C. Hydrogel
- D. Silicone
Explanation: ***PMMA*** - **Polymethylmethacrylate (PMMA)** is a rigid, non-foldable material historically used for **intraocular lenses (IOLs)**. - Due to its rigidity, PMMA IOLs require a **larger incision** for implantation, which can lead to astigmatism and slower recovery. *Silicone* - **Silicone** is a flexible, foldable material commonly used for modern IOLs, allowing for **smaller incisions**. - It has excellent **elastic properties** but may be associated with certain risks in eyes with silicone oil. *Acrylic* - **Acrylic** (both hydrophobic and hydrophilic) is a popular material for foldable IOLs, known for its **biocompatibility** and ability to be inserted through small incisions. - It is currently the most widely used material due to its **foldable nature** and good optical qualities. *Hydrogel* - **Hydrogel** is a type of hydrophilic acrylic material, characterized by its **high water content** and flexibility. - While foldable, hydrogel IOLs are less commonly used than other acrylic types, partly due to some concerns about long-term clarity or calcification in certain formulations.
Question 953: Rigid gas permeable (RGP) lenses are made from which of the following combinations of materials?
- A. Hydroxymethylmethacrylate
- B. Cellulose acetate Butyrate
- C. Polymethylmethacrylate
- D. Copolymer of PMMA, Silicon containing monomer & cellulose acetyl butyrate (Correct Answer)
Explanation: ***Copolymer of PMMA, Silicon containing monomer & cellulose acetyl butyrate*** - **Rigid gas permeable (RGP) lenses** are designed to be permeable to oxygen, which is achieved through the incorporation of **silicon-containing monomers**. - The combination of **PMMA** (for rigidity), **silicon** (for oxygen permeability), and **cellulose acetyl butyrate** (for improved wettability and flexibility) provides the desired mechanical and optical properties. *Polymethylmethacrylate* - **PMMA** was the primary material for the earliest **hard contact lenses** but offered virtually no oxygen permeability. - This lack of oxygen permeability led to significant corneal hypoxia issues and limited wear time. *Hydroxymethylmethacrylate* - **Hydroxymethylmethacrylate (HEMA)** is a key material in **hydrogel soft contact lenses**, known for its ability to absorb water. - HEMA is not used in RGP lenses because it would make the lens soft and flexible, contrary to the "rigid" characteristic. *Cellulose acetate Butyrate* - **Cellulose acetate butyrate (CAB)** was an early material used for **gas permeable lenses**, offering some oxygen permeability. - While it was an improvement over PMMA, it did not achieve the high level of oxygen permeability seen with newer silicon-containing materials.