Anatomy
1 questionsWhich part of the bone is considered the most vascular zone?
NEET-PG 2015 - Anatomy NEET-PG Practice Questions and MCQs
Question 951: Which part of the bone is considered the most vascular zone?
- A. Metaphysis (Correct Answer)
- B. Diaphysis
- C. Epiphysis
- D. Medullary Cavity
Explanation: ***Metaphysis*** - The metaphysis is the most **vascular** part of the bone, containing numerous blood vessels that supply the growing bone. - This high vascularity makes it a common site for **osteomyelitis** and bone tumors due to the abundant blood supply [1]. *Diaphysis* - The diaphysis is the **shaft** or central part of a long bone, primarily composed of **compact bone** [2]. - While it has blood supply through nutrient arteries, its vascularity is less dense compared to the metaphysis. *Epiphysis* - The epiphysis is the **end portion** of a long bone, typically covered by articular cartilage. - It receives its blood supply from periarticular vessels, but is less vascular than the metaphysis, especially in mature bone. *Medullary Cavity* - The medullary cavity is the central cavity of bone shafts where **bone marrow** is stored [2]. - While it contains hematopoietic stem cells and a rich blood supply, the surrounding bone tissue of the metaphysis itself is considered more vascular in terms of nutrient delivery and growth.
Internal Medicine
7 questionsWhich of the following is NOT a criterion for the diagnosis of Primary Hyperaldosteronism?
Most common cause of Addison's Disease in India is:
Female with blood sugar of 600 mg% and sodium of 110 mEq. Insulin was given, what will happen to serum sodium levels ?
What condition is characterized by hypertension and hypokalemia?
Which of the following is the MOST common condition caused by hypernatremia?
Which 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?
NEET-PG 2015 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 951: Which of the following is NOT a criterion for the diagnosis of Primary Hyperaldosteronism?
- A. Diastolic Hypertension without edema
- B. Low Plasma Renin Activity
- C. Hyperkalemia (Correct Answer)
- D. Hyperaldosteronism which is not suppressed by volume expansion
Explanation: Primary hyperaldosteronism is typically characterized by **hypokalemia** due to excessive aldosterone-mediated potassium excretion in the urine, not hyperkalemia [1]. Hyperkalemia would suggest other conditions, such as **adrenal insufficiency** or kidney disease, rather than primary hyperaldosteronism [2]. *Diastolic Hypertension without edema* - **Diastolic hypertension** is a common presentation of primary hyperaldosteronism due to increased **sodium and water retention**, leading to expanded extracellular volume. - The absence of significant edema is also common, as the body often develops an **"escape phenomenon"** where natriuresis occurs despite high aldosterone, preventing overt fluid overload [3]. *Low Plasma Renin Activity* - In primary hyperaldosteronism, the high aldosterone levels **suppress renin secretion** through negative feedback mechanisms. - Therefore, a **low plasma renin activity** (PRA) or plasma renin concentration (PRC) is a key diagnostic feature [4]. *Hyperaldosteronism which is not suppressed by volume expansion* - Normally, volume expansion would suppress aldosterone secretion. However, in primary hyperaldosteronism, aldosterone production is **autonomous** and remains elevated even after volume expansion. - This lack of suppression is a critical diagnostic criterion, often assessed through various **confirmatory tests** like saline infusion or oral sodium loading.
Question 952: Most common cause of Addison's Disease in India is:
- A. Autoimmune
- B. HIV
- C. Tuberculosis (Correct Answer)
- D. Malignancy
Explanation: ***Tuberculosis*** - In India, **tuberculosis** is the most common cause of **Addison's disease** due to the high prevalence of TB infections. - Adrenal involvement in TB can lead to gradual destruction of the adrenal cortex, resulting in **adrenal insufficiency**. *Autoimmune* - **Autoimmune adrenalitis** is the leading cause of Addison's disease in developed Western countries. - It involves the destruction of adrenal cortical cells by the body's own immune system, often associated with other autoimmune conditions. *Malignancy* - **Malignancy**, particularly metastatic cancer to the adrenals, can cause adrenal insufficiency but is a less common primary cause of Addison's disease overall. - While possible, it is not the most prevalent cause in India compared to infectious etiologies. *HIV* - **HIV infection** can lead to adrenal dysfunction, but it's typically through opportunistic infections like CMV, cryptococcosis, or direct HIV effects, rather than being the direct cause of widespread adrenal destruction. - It increases the risk of adrenal insufficiency but is not the most common etiology in India for Addison's disease.
Question 953: Female with blood sugar of 600 mg% and sodium of 110 mEq. Insulin was given, what will happen to serum sodium levels ?
- A. Sodium levels may appear to increase (Correct Answer)
- B. Sodium levels decrease
- C. Sodium levels remain unchanged
- D. Relative sodium deficiency may occur
Explanation: ***Sodium levels may appear to increase*** - The patient's initial presentation with severe hyperglycemia (600 mg%) and hyponatremia (110 mEq/L) suggests **hyperglycemia-induced pseudohyponatremia**. - **Insulin administration** will lower blood glucose, causing water to shift back into the cells from the extracellular space, thereby correcting the dilutional effect and leading to an **apparent increase in serum sodium levels**. *Sodium levels decrease* - This is incorrect because the hyponatremia in this scenario is largely **dilutional** due to hyperglycemia. - As glucose levels decrease with insulin, the osmotic drive for water movement out of cells diminishes, leading to **normalization**, not further decrease, of sodium concentration. *Sodium levels remain unchanged* - This is incorrect because the underlying cause of the initial low sodium is dilution from high glucose. - Once **hyperglycemia is treated**, the osmotic gradient changes, and water shifts, directly impacting and changing the serum sodium concentration. *Relative sodium deficiency may occur* - This option is incorrect because the initial hyponatremia is not primarily due to an absolute lack of sodium in the body but rather a **dilutional effect** caused by the osmotic pull of glucose. - As hyperglycemia resolves, the extracellular fluid becomes less diluted, and the measured sodium concentration will **rise**, not indicate a deficiency.
Question 954: What condition is characterized by hypertension and hypokalemia?
- A. Gitelman's Syndrome
- B. Liddle's Syndrome (Correct Answer)
- C. Bartter Syndrome
- D. All of the options
Explanation: ***Liddle's Syndrome*** - This syndrome is characterized by **overactivity of the epithelial sodium channel (ENaC)** in the collecting ducts, leading to increased sodium reabsorption and potassium excretion. [1] - The resulting **sodium retention causes hypertension**, while the **potassium excretion leads to hypokalemia**. *Gitelman's Syndrome* - This is an **autosomal recessive kidney disorder** causing a defect in the **thiazide-sensitive NaCl cotransporter** in the distal convoluted tubule. - It presents with **hypokalemia and hypomagnesemia**, but typically with **normal or low blood pressure**, not hypertension. *Bartter Syndrome* - This is a group of **autosomal recessive salt-wasting tubulopathies** affecting the **Na-K-2Cl cotransporter** in the thick ascending limb of the loop of Henle. - It leads to **hypokalemia, metabolic alkalosis, and normal or low blood pressure**, similar to chronic loop diuretic use. *All of the options* - While all mentioned conditions involve **hypokalemia**, only **Liddle's Syndrome** is consistently associated with **hypertension**. - **Gitelman's and Bartter syndromes** typically present with **normal or low blood pressure**.
Question 955: Which of the following is the MOST common condition caused by hypernatremia?
- A. Altered mental status
- B. Brain hemorrhage
- C. Seizure (Correct Answer)
- D. Central pontine myelinosis
Explanation: ***Seizure*** - While not the *most* common initial symptom, **seizure** can be a severe manifestation of hypernatremia, particularly when the serum sodium levels rise rapidly or to very high concentrations leading to significant neuronal dehydration. - **Rapid correction of severe hypernatremia** can also induce seizures if the brain cells swell too quickly. *Altered mental status* - **Altered mental status** such as lethargy, confusion, or irritability, is a very common and often an earlier symptom of hypernatremia due to neuronal dehydration and intracellular water shifts, but it generally precedes more severe neurological complications like seizures.[1] - It is a broad term that encompasses a range of neurological dysfunctions, and while frequent, it is not as specific a severe endpoint as a seizure. *Brain hemorrhage* - **Brain hemorrhage** is a rare and severe complication of hypernatremia, primarily seen when extreme osmotic shifts cause significant brain shrinkage, leading to tension on bridging veins and potential rupture. - This is not a common presentation and typically occurs only in very severe cases of hypernatremia or during overly rapid correction. *Central pontine myelinosis* - **Central pontine myelinolysis (CPM)** is a neurological disorder caused by too rapid correction of *chronic hyponatremia*, not hypernatremia.[1] - It results from osmotic damage to myelin sheaths in the pons, leading to severe neurological deficits such as dysphagia, dysarthria, and even locked-in syndrome.[1]
Question 956: 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 957: 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.
Obstetrics and Gynecology
1 questionsWhat is the primary clinical advantage of the occipitoanterior position in childbirth?
NEET-PG 2015 - Obstetrics and Gynecology NEET-PG Practice Questions and MCQs
Question 951: What is the primary clinical advantage of the occipitoanterior position in childbirth?
- A. It is the most favorable position for vaginal delivery.
- B. It allows optimal fetal head flexion reducing the presenting diameter. (Correct Answer)
- C. Anterior fontanelle is anterior in this position.
- D. It is associated with shorter labor duration and fewer complications.
Explanation: ***It allows optimal fetal head flexion reducing the presenting diameter.*** - In the occipitoanterior (OA) position, the fetal head is **well-flexed**, allowing the **smallest diameter** of the fetal head to present to the maternal pelvis - The presenting diameter is the **suboccipitobregmatic diameter** (~9.5 cm), which is the smallest anteroposterior diameter of the fetal head - This optimal flexion is the **primary clinical advantage** as it facilitates easier passage through the birth canal and reduces maternal and fetal trauma - The **occiput (posterior fontanelle)** faces anteriorly in this position, which is a key anatomical landmark used to diagnose OA position during vaginal examination *It is the most favorable position for vaginal delivery.* - While this statement is true, it is **too general** and doesn't explain the specific anatomical or mechanical reason - It describes an outcome rather than explaining the **primary clinical advantage** in terms of fetal head mechanics *Anterior fontanelle is anterior in this position.* - This statement is **anatomically incorrect** - In occipitoanterior position, the **occiput (posterior fontanelle)** is anterior, not the anterior fontanelle - The anterior fontanelle (bregma) is actually positioned **posteriorly** in the OA position *It is associated with shorter labor duration and fewer complications.* - This is a **consequence** of the favorable OA position, not the primary clinical advantage itself - The shorter labor and fewer complications result from the optimal fetal head flexion and smaller presenting diameter - This option describes an **outcome** rather than the underlying anatomical/mechanical advantage
Physiology
1 questionsOsteoclasts have all of the following functions except -
NEET-PG 2015 - Physiology NEET-PG Practice Questions and MCQs
Question 951: Osteoclasts have all of the following functions except -
- A. Receptor for parathormone (Correct Answer)
- B. Ruffled border
- C. Bone resorption
- D. RANK ligand production
Explanation: ***Receptor for parathormone*** - **Osteoclasts** do not directly have receptors for **parathormone (PTH)**; instead, **osteoblasts** have PTH receptors. - When PTH binds to osteoblasts, they release factors (like **RANKL**) that stimulate osteoclast activity, thus indirectly regulating bone resorption. *Bone resorption* - **Osteoclasts** are specialized cells primarily responsible for **resorbing bone matrix**, a critical process in bone remodeling. - They secrete **acids and enzymes** to break down the mineral and organic components of bone. *Ruffled border* - The **ruffled border** is a characteristic morphological feature of active osteoclasts, representing a highly folded plasma membrane. - This specialized structure increases the surface area for the secretion of **protons and lysosomal enzymes** into the bone-resorbing compartment. *RANK ligand production* - **Osteoclasts** do not produce **RANK ligand (RANKL)**; rather, they have **RANK receptors** that bind to RANKL produced by **osteoblasts and stromal cells**. - The binding of RANKL to RANK is essential for the **differentiation, activation, and survival** of osteoclasts.