Anatomy
1 questionsWhich of the following is a cerebellar nucleus?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 271: Which of the following is a cerebellar nucleus?
- A. Putamen
- B. Caudate nucleus
- C. Subthalamic nucleus
- D. Fastigial nucleus (Correct Answer)
Explanation: ***Fastigial nucleus*** - The **fastigial nucleus** is one of the four principal deep cerebellar nuclei, involved in regulating **balance** and **posture** [2]. - The deep cerebellar nuclei are crucial for the cerebellum's output, relaying processed information to other brain regions [2]. *Caudate nucleus* - The **caudate nucleus** is part of the **basal ganglia**, a group of subcortical nuclei in the forebrain [1]. - It plays a significant role in **motor control**, learning, memory, and reward processing. *Subthalamic nucleus* - The **subthalamic nucleus** is a small nucleus located in the **diencephalon**, below the thalamus and above the substantia nigra [1]. - It is also part of the **basal ganglia system** and is critical for modulating motor control [1]. *Putamen* - The **putamen** is another structure belonging to the **basal ganglia**, located in the forebrain [1]. - It is primarily involved in regulating various types of **motor behavior** and learning.
Biochemistry
1 questionsWhat is the unit for a prolactin level of 20 in blood?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 271: What is the unit for a prolactin level of 20 in blood?
- A. ng/ml (Correct Answer)
- B. mg/ml
- C. mg/l
- D. ng/l
Explanation: ***ng/ml*** - Prolactin levels in blood are typically measured in **nanograms per milliliter (ng/mL)**, reflecting the very small concentrations of hormones. - A value of 20 ng/mL falls within the typical reference range for prolactin. *mg/mL* - **Milligrams per milliliter (mg/mL)** is a unit used for much higher concentrations, more common for drugs or larger molecules, not hormones like prolactin. - If prolactin were measured in mg/mL, a value of 20 mg/mL would be an astronomically high and physiologically impossible level. *mg/L* - **Milligrams per liter (mg/L)** is also a unit for higher concentrations than those typically seen for hormones in blood. - 20 mg/L is equivalent to 20 µg/mL or 20,000 ng/mL, which would indicate severe hyperprolactinemia. *ng/L* - **Nanograms per liter (ng/L)** is a unit for extremely low concentrations. - A reading of 20 ng/L would be too low for normal physiological prolactin levels, as 1 ng/mL equals 1000 ng/L.
Pathology
2 questionsAll of the following are true regarding fibromuscular dysplasia EXCEPT:
Which of the following is a primary pleural tumor?
NEET-PG 2013 - Pathology NEET-PG Practice Questions and MCQs
Question 271: All of the following are true regarding fibromuscular dysplasia EXCEPT:
- A. Medium size vessels are affected
- B. Aneurysm may occur
- C. Irregular hyperplasia
- D. OCPs predispose (Correct Answer)
Explanation: ***OCPs predispose*** - **Oral contraceptive pills (OCPs)** are not identified as a predisposing factor for fibromuscular dysplasia (FMD). FMD is largely considered a sporadic condition with some genetic predisposition, but not linked to OCP use [1]. - While hormonal influences are suspected given its higher prevalence in women, direct causation or exacerbation by OCPs has not been established [1]. *Medium size vessels are affected* - Fibromuscular dysplasia (FMD) predominantly affects **medium-sized arteries**, most commonly the renal and carotid arteries [1]. - This involvement leads to characteristic stenoses, aneurysms, or dissections in those vessels. *Aneurysm may occur* - The abnormal arterial wall architecture in FMD, characterized by alternating areas of stenosis and dilation, can lead to the formation of **aneurysms**. - These aneurysms are usually **intracranial** or within the affected renal and carotid arteries, and represent a significant risk of rupture or dissection. *Irregular hyperplasia* - FMD involves **irregular fibrous or fibromuscular hyperplasia** of the arterial wall layers (intima, media, or adventitia). - This abnormal cellular proliferation and connective tissue deposition result in the characteristic "string of beads" appearance on angiography. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of Infancy and Childhood, pp. 493-494.
Question 272: Which of the following is a primary pleural tumor?
- A. Mesothelioma (Correct Answer)
- B. Myxoma
- C. Lipoma
- D. None of the options
Explanation: ***Mesothelioma*** - Mesothelioma is a **primary malignant tumor** of the pleura [1], commonly associated with **asbestos exposure** [2]. - It typically presents with symptoms like **pleuritic chest pain**, dyspnea, and pleural effusion. *Myxoma* - Myxoma is a **benign tumor** primarily found in the **heart**, particularly in the left atrium, not in the pleura. - It does not arise from pleural tissue and lacks the **malignant characteristics** of mesothelioma. *All* - This option suggests that multiple tumors can be primary pleural tumors, which is incorrect as only mesothelioma is recognized as such. - Other tumors like myxoma and lipoma do not originate in the pleura and thus cannot be classified as primary pleural tumors. *Lipoma* - Lipoma is a **benign tumor** made up of adipose tissue [3] and is typically found in *subcutaneous tissue*, not the pleural cavity. - It does not have the malignant potential or association with pleural disease that characterizes mesothelioma. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Lung, pp. 728-729. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Respiratory Tract Disease, pp. 339-340. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Bones, Joints, and Soft Tissue Tumors, p. 1222.
Physiology
6 questionsLowest pH is seen in which of the gastrointestinal secretions?
What is the most important extracellular buffer?
Daily salivary secretion is
Which of the following does not have sympathetic noradrenergic fibers?
All should be features of a substance to measure GFR, except?
Inhibition of myenteric plexus results in
NEET-PG 2013 - Physiology NEET-PG Practice Questions and MCQs
Question 271: Lowest pH is seen in which of the gastrointestinal secretions?
- A. Gastric juice (Correct Answer)
- B. Bile juice
- C. Saliva
- D. Pancreatic juice
Explanation: ***Gastric juice*** - Gastric juice contains **hydrochloric acid (HCl)**, secreted by parietal cells, which gives it a very **low pH (1.5-3.5)**. - This acidic environment is crucial for protein digestion by **pepsin** and for killing ingested microorganisms. *Bile juice* - Bile juice is typically **alkaline**, with a pH ranging from **7.6 to 8.6**. - Its primary role is to **emulsify fats** in the small intestine, and it does not contain significant acidic components. *Saliva* - Saliva has a relatively neutral pH, typically ranging from **6.2 to 7.6**. - It contains enzymes like **amylase** and **lipase** for initial carbohydrate and lipid digestion, but no strong acids. *Pancreatic juice* - Pancreatic juice is highly **alkaline**, with a pH usually between **8.0 and 8.3**, due to its high concentration of bicarbonate. - This alkalinity neutralizes the acidic chyme entering the duodenum from the stomach, creating an optimal environment for pancreatic enzymes.
Question 272: What is the most important extracellular buffer?
- A. Bicarbonates (Correct Answer)
- B. Phosphate buffer
- C. Plasma protein buffer
- D. Ammonium buffer
Explanation: ***Bicarbonates*** - The **bicarbonate buffer system** is the most important extracellular buffer because its components (carbonic acid and bicarbonate) are present in high concentrations and their levels can be regulated by both the lungs (CO2 excretion) and the kidneys (bicarbonate reabsorption/secretion). - Its pKa (6.1) makes it an effective buffer against metabolically produced acids, which frequently challenge blood pH. *Phosphate buffer* - The **phosphate buffer system** is more important as an intracellular buffer and in renal tubular fluid due to its higher concentration in these compartments. - Its concentration in the extracellular fluid is relatively low compared to bicarbonate, limiting its capacity as the primary extracellular buffer. *Plasma protein buffer* - **Plasma proteins**, particularly albumin, have numerous ionizable groups and contribute to buffering in the extracellular fluid. - However, their overall buffering capacity is less significant than that of the bicarbonate system due to lower concentration compared to bicarbonate and less dynamic regulation. *Ammonium buffer* - The **ammonium buffer system** (ammonia/ammonium) is primarily important for acid-base regulation by the kidneys, where it plays a critical role in excreting excess acid, particularly in chronic acidosis. - It is not a major extracellular fluid buffer in the systemic circulation under normal physiological conditions.
Question 273: Daily salivary secretion is
- A. 1000-1500 ml (Correct Answer)
- B. 1500-2000 ml
- C. More than 2000 ml
- D. Less than 1000 ml
Explanation: ***1000-1500 ml*** - The average daily salivary secretion in healthy adults ranges from **1000 to 1500 ml**, with variations depending on individual factors and stimulation. - This volume is crucial for various functions, including **digestion**, oral hygiene, and speech. *1500-2000 ml* - This range is generally considered to be on the **higher side** of normal daily salivary output, exceeding the typical average. - While individual variations exist, consistent secretion at this level might suggest **hypersecretion** or ptyalism in some cases. *More than 2000 ml* - Daily salivary secretion **rarely exceeds 2000 ml** in healthy individuals. - Such high volumes could indicate a pathological condition leading to **sialorrhea** or excessive salivation. *Less than 1000 ml* - A daily salivary secretion of **less than 1000 ml** is often indicative of **hyposalivation** or dry mouth (xerostomia). - This reduced volume can lead to problems with chewing, swallowing, speaking, and an increased risk of dental caries.
Question 274: Which of the following does not have sympathetic noradrenergic fibers?
- A. Heart
- B. Eye
- C. Sweat gland (Correct Answer)
- D. Blood vessels
Explanation: ***Sweat gland*** - While sweat glands are innervated by the **sympathetic nervous system**, their postganglionic fibers are **cholinergic**, releasing **acetylcholine** rather than noradrenaline. - This is an important exception where sympathetic stimulation leads to acetylcholine release, causing sweating. *Blood vessels* - Most blood vessels, particularly resistance vessels such as **arterioles**, receive substantial **sympathetic noradrenergic innervation** that causes vasoconstriction. - This sympathetic tone is crucial for regulating **blood pressure** and distributing blood flow. *Heart* - The heart is richly innervated by **sympathetic noradrenergic fibers** that increase **heart rate**, **contractility**, and **conduction velocity** via beta-1 adrenergic receptors. - This makes noradrenaline a key neurotransmitter in the sympathetic regulation of cardiac function. *Eye* - The eye receives sympathetic noradrenergic innervation primarily to the **dilator pupillae muscle**, causing **mydriasis** (pupil dilation) upon activation. - These fibers also contribute to the sympathetic control of the **tarsal muscle** (Müller's muscle) in the eyelid.
Question 275: All should be features of a substance to measure GFR, except?
- A. Freely reabsorbed (Correct Answer)
- B. Not secreted by kidney
- C. Freely filtered across the glomerulus membrane
- D. None of the options
Explanation: ***Freely reabsorbed*** - A substance used to measure GFR should **not be reabsorbed** by the kidney tubules. If it were reabsorbed, the amount excreted in the urine would be less than the amount filtered, leading to an **underestimation of GFR**. - The ideal GFR marker is **neither reabsorbed nor secreted**, ensuring that its excretion rate directly reflects the filtration rate. *Freely filtered across the glomerulus membrane* - For a substance to accurately measure GFR, it must be **freely filtered** from the blood into the Bowman's capsule, without any restriction due to its size or charge. - This ensures that its concentration in the glomerular filtrate is the same as in the plasma, allowing for a direct calculation of the filtration rate. *Not secreted by kidney* - An ideal GFR marker should **not be secreted** by the renal tubules, as active secretion would add to the amount excreted in the urine, leading to an **overestimation of GFR**. - This property, along with not being reabsorbed, ensures that the amount of the substance appearing in the urine solely reflects the amount filtered. *None of the options* - This option is incorrect because there is a definitive feature listed among the choices that is *not* a characteristic of an ideal GFR marker. The ability to be "freely reabsorbed" is a disqualifying trait.
Question 276: Inhibition of myenteric plexus results in
- A. Hyperacidity
- B. Diarrhea
- C. Decreased gut motility (Correct Answer)
- D. Increased secretions
Explanation: ***Decreased gut motility*** - The **myenteric plexus** (Auerbach's plexus) is primarily responsible for regulating **gastrointestinal motility**, including peristalsis and muscle contraction. - Its inhibition would therefore lead to **reduced peristaltic movements** and **decreased gut motility**. *Hyperacidity* - **Gastric acid secretion** is mainly regulated by the vagus nerve (via acetylcholine), gastrin, and histamine, not directly by the myenteric plexus. - While gut motility can indirectly affect acid exposure, a primary and direct consequence of myenteric plexus inhibition is not hyperacidity. *Diarrhea* - **Diarrhea** is typically caused by increased gut motility, increased secretion, or decreased absorption. - Inhibition of the myenteric plexus would lead to **decreased motility**, making diarrhea an unlikely outcome. *Increased secretions* - **Gastrointestinal secretions** are largely controlled by the submucosal plexus (Meissner's plexus) and hormonal factors. - While the myenteric plexus has some indirect influence, its primary role is motility, and its inhibition would not directly lead to increased secretions.