Anatomy
1 questionsWhich Brodmann's area is primarily associated with motor speech?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 251: Which Brodmann's area is primarily associated with motor speech?
- A. Area 1, 2, 3
- B. Area 4, 6
- C. Area 40
- D. Area 44 (Correct Answer)
Explanation: Area 44 - **Brodmann Area 44** is primarily known as **Broca's area**, which is critical for **motor speech production** and language processing [1]. - Damage to this area typically results in **Broca's aphasia**, characterized by non-fluent speech and difficulty forming complete sentences [1]. Area 1, 2, 3 - These Brodmann areas constitute the **primary somatosensory cortex**, responsible for processing **tactile and proprioceptive information** from the body. - They are involved in sensory perception, not directly with motor speech production. Area 4, 6 - **Brodmann Area 4** is the **primary motor cortex**, involved in executing voluntary movements [2]. **Brodmann Area 6** is the **premotor and supplementary motor cortex**, involved in planning and coordinating movements [2]. - While these areas are crucial for motor control, they are not specifically associated as the primary center for motor speech in the same way Broca's area is. Area 40 - **Brodmann Area 40**, also known as the **supramarginal gyrus**, is part of the **parietal lobe** and is involved in phonological processing, language perception, and spatial cognition. - While it plays a role in language, it is not the primary area for motor speech production.
Biochemistry
1 questionsGlucagon activates which enzyme ?
NEET-PG 2015 - Biochemistry NEET-PG Practice Questions and MCQs
Question 251: Glucagon activates which enzyme ?
- A. Adenylyl cyclase (Correct Answer)
- B. Pepsin
- C. Trypsin
- D. None of the options
Explanation: ***Adenylyl cyclase*** - **Glucagon** binds to specific G protein-coupled receptors on target cells, activating the **Gαs subunit**. - The activated **Gαs subunit** then stimulates **adenylyl cyclase**, leading to the production of **cyclic AMP (cAMP)**, which mediates glucagon's metabolic effects. *Pepsin* - **Pepsin** is a protease produced in the stomach, involved in protein digestion, and its activity is regulated by **gastrin** and **acid secretion**, not glucagon. - It is synthesized as **pepsinogen** and activated by hydrochloric acid (HCl) at low pH. *Trypsin* - **Trypsin** is a digestive enzyme produced in the pancreas and secreted into the small intestine, primarily involved in protein digestion. - Its activation is dependent on **enteropeptidase**, which cleaves **trypsinogen**, and its activity is not directly regulated by glucagon. *None of the options* - This option is incorrect because **adenylyl cyclase** is indeed activated by glucagon as part of its signaling pathway.
Community Medicine
1 questionsCaisson's disease is primarily associated with which of the following?
NEET-PG 2015 - Community Medicine NEET-PG Practice Questions and MCQs
Question 251: Caisson's disease is primarily associated with which of the following?
- A. None of the options
- B. Underwater construction workers (Correct Answer)
- C. Rapid ascent in aircraft
- D. Rapid ascent of deep sea divers
Explanation: ***Underwater construction workers*** - Caisson's disease, also known as **decompression sickness (DCS)**, is historically linked to workers in **caissons**, which are watertight structures used for underwater construction. - These workers experience changes in pressure that can lead to nitrogen bubbles forming in their tissues upon surfacing, causing the characteristic symptoms of DCS. *Rapid ascent in aircraft* - While rapid ascent in aircraft can cause **decompression sickness**, especially in unpressurized cabins, it is not the primary association for the historical term "Caisson's disease." - The term "Caisson's disease" specifically refers to the condition in workers exposed to **high atmospheric pressure** during underwater construction. *None of the options* - This option is incorrect because **underwater construction workers** are directly associated with Caisson's disease. - The question has a correct and specific answer. *Rapid ascent of deep sea divers* - **Deep-sea divers** are susceptible to decompression sickness due to rapid ascent, which is physiologically similar to Caisson's disease. - However, the specific term "Caisson's disease" most directly refers to the historical experience of **underwater construction workers** in caissons.
Internal Medicine
1 questionsWhat is the immediate emergency treatment for carbon monoxide (CO) poisoning?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 251: What is the immediate emergency treatment for carbon monoxide (CO) poisoning?
- A. 5% CO2 inhalation
- B. 10% CO2 inhalation
- C. High flow O2 (Correct Answer)
- D. Nitroglycerine
Explanation: ***High flow O2*** - **High-flow oxygen** is the immediate emergency treatment for CO poisoning because it helps to displace CO from **hemoglobin**, thereby increasing oxygen delivery to tissues [1], [2]. - CO has a much **higher affinity** for hemoglobin than oxygen, so administering high concentrations of oxygen helps to reverse this binding and accelerate CO elimination [2]. *5% CO2 inhalation* - Administering **CO2** would worsen the patient's condition as it can cause **respiratory acidosis** and increase cerebral blood flow, potentially exacerbating CO toxicity. - CO2 inhalation would not effectively displace **carbon monoxide** from hemoglobin. *10% CO2 inhalation* - Similar to 5% CO2, **10% CO2 inhalation** would be detrimental, leading to significant **acidosis** and further compromising respiratory function. - This treatment does not address the primary issue of **carbon monoxide** binding to **hemoglobin** [2]. *Nitroglycerine* - **Nitroglycerine** is a vasodilator primarily used for conditions like **angina** or **heart failure**; it has no role in treating CO poisoning. - It would not help in displacing **carbon monoxide** or improving tissue oxygenation.
Pathology
1 questionsWhat is the primary process involved in Wallerian degeneration?
NEET-PG 2015 - Pathology NEET-PG Practice Questions and MCQs
Question 251: What is the primary process involved in Wallerian degeneration?
- A. Nerve degeneration (Correct Answer)
- B. Muscle degeneration
- C. Nerve regeneration
- D. Muscle regeneration
Explanation: ***Nerve degeneration*** - **Wallerian degeneration** specifically refers to the process of **axon degeneration** that occurs distal to the site of injury when a nerve fiber is severed [2]. - This process involves the breakdown of the **axon** and its myelin sheath, leading to loss of function [1]. *Muscle degeneration* - While prolonged nerve degeneration can lead to muscle **atrophy** due to denervation, **muscle degeneration itself** is not the primary process of Wallerian degeneration. - Wallerian degeneration focuses on the **nerve itself**, not the target tissue. *Nerve regeneration* - **Nerve regeneration** is the process where damaged nerves attempt to regrow and re-establish connections [2]. - This is a subsequent, and not always successful, event that can occur *after* Wallerian degeneration has cleared the debris [1]. *Muscle regeneration* - **Muscle regeneration** refers to the repair and regrowth of damaged muscle tissue, typically involving satellite cells. - It is unrelated to Wallerian degeneration, which is a process affecting the **nerve**. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 697-698. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 109-110.
Physiology
5 questionsBroca's area is primarily involved in which of the following functions?
Which of the following receptors is stimulated by sustained pressure?
Vibrations are detected by which types of receptors?
Tetany in muscle occurs in spite of normal serum Ca2+ level. Which ion is responsible?
What is another name for the withdrawal reflex?
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 251: Broca's area is primarily involved in which of the following functions?
- A. Speech production (Correct Answer)
- B. Language comprehension
- C. Language repetition
- D. Reading ability
Explanation: ***Speech production*** - **Broca's area** is a region in the frontal lobe of the dominant hemisphere, typically the left, that is crucial for the formation of coherent and grammatically correct speech. - Damage to this area leads to **Broca's aphasia**, characterized by **non-fluent speech**, difficulty retrieving words, and impaired syntax. *Language comprehension* - **Wernicke's area**, located in the temporal lobe, is primarily responsible for **language comprehension**. - Patients with **Wernicke's aphasia** can produce fluent speech but have difficulty understanding spoken and written language. *Language repetition* - The **arcuate fasciculus**, a bundle of nerve fibers connecting Broca's and Wernicke's areas, is essential for **language repetition**. - Lesions in this pathway result in **conduction aphasia**, where comprehension and fluency are relatively preserved, but repetition is severely impaired. *Reading ability* - Reading ability involves a complex network of brain regions, including the **angular gyrus** and **visual cortex**, in addition to language areas. - While Broca's area contributes to the motor planning aspects of reading aloud, it is not its primary function.
Question 252: Which of the following receptors is stimulated by sustained pressure?
- A. Ruffini's end organ (Correct Answer)
- B. Merkel's disc
- C. Hair cells
- D. Meissner Corpuscles
Explanation: ***Ruffini's end organ*** - These are **slowly adapting mechanoreceptors** located deep in the dermis and subcutaneous tissue. - They are responsible for detecting **sustained pressure**, stretch, and position sense. *Merkel's disc* - These are **slowly adapting mechanoreceptors** found in the basal epidermis. - They are crucial for sensing **light touch** and **two-point discrimination**. *Hair cells* - These are **mechanoreceptors** primarily found in the inner ear, responsible for hearing and balance. - They are not involved in the perception of somatosensory stimuli like pressure on the skin. *Meissner Corpuscles* - These are **rapidly adapting mechanoreceptors** located in the dermal papillae, close to the skin surface. - They are primarily involved in detecting **light touch** and **discriminative touch**, especially changes in texture.
Question 253: Vibrations are detected by which types of receptors?
- A. Slowly adapting
- B. Rapidly adapting (Correct Answer)
- C. Non-adapting
- D. None of the above
Explanation: ***Rapidly adapting*** - **Rapidly adapting mechanoreceptors**, such as **Pacinian corpuscles** and **Meissner's corpuscles**, are highly sensitive to changes in pressure and movement. - They fire at the **onset and offset of a stimulus**, making them ideal for detecting vibrations, which are rhythmic changes in pressure. *Slowly adapting* - **Slowly adapting mechanoreceptors**, such as **Merkel cells** and **Ruffini endings**, are responsible for sustained pressure and touch. - They continue to fire as long as the stimulus is present, making them less suited for detecting transient vibratory stimuli. *Non-adapting* - The human body does not typically have **truly non-adapting** sensory receptors; most receptors show some form of adaptation to continuous stimuli. - This term is not standard in the classification of mechanoreceptors based on their adaptation rates. *None of the above* - This option is incorrect because rapidly adapting receptors are indeed responsible for detecting vibrations.
Question 254: Tetany in muscle occurs in spite of normal serum Ca2+ level. Which ion is responsible?
- A. Mg2+
- B. K+
- C. Na+
- D. Ionized Ca2+ (Correct Answer)
Explanation: ***Ionized Ca2+*** - While total serum calcium might be normal, **tetany** is specifically caused by a decrease in the concentration of **ionized (free) calcium** in the extracellular fluid. - Ionized calcium is the physiologically active form of calcium responsible for neuromuscular excitability. *Mg2+* - **Hypomagnesemia** can exacerbate hypocalcemia and contribute to tetany, but it is not the primary ion directly responsible for tetany when **total serum calcium is normal**. - A deficiency in Mg2+ can impair the release of **parathyroid hormone** and reduce target organ responsiveness to PTH. *K+* - Abnormalities in **potassium levels** (hypokalemia or hyperkalemia) primarily affect cardiac and muscular excitability, leading to arrhythmias or muscle weakness/paralysis. - While electrolyte imbalances are interconnected, changes in potassium are not the direct cause of tetany due to calcium's role. *Na+* - **Sodium ions** are crucial for nerve impulse transmission and muscle contraction by establishing the resting membrane potential and initiating action potentials. - However, direct changes in sodium concentration do not typically cause tetany; rather, they can lead to neurological symptoms like seizures (hyponatremia) or altered mental status (hypernatremia).
Question 255: What is another name for the withdrawal reflex?
- A. Golgi tendon reflex
- B. Extension reflex
- C. Stretch reflex
- D. Flexor reflex (Correct Answer)
Explanation: ***Flexor reflex*** - The withdrawal reflex is also known as the **flexor reflex** because it causes the rapid flexion (bending) of a limb to withdraw it from a noxious stimulus. - This reflex is a **polysynaptic reflex** involving interneurons in the spinal cord. *Golgi tendon reflex* - The **Golgi tendon reflex** is a protective reflex that causes muscle relaxation in response to excessive muscle tension. - It involves activation of **Golgi tendon organs**, which are proprioceptors located in the tendons. *Extension reflex* - The **extension reflex** is typically observed in withdrawal reflexes of the opposing limb, known as the **crossed extensor reflex**, to maintain balance. - It involves the extension of the contralateral limb while the ipsilateral limb flexes. *Stretch reflex* - The **stretch reflex** (or myotatic reflex) causes muscle contraction in response to stretching of the muscle. - It is a **monosynaptic reflex** involving muscle spindles and maintaining muscle tone.