Anatomy
1 questionsJoint involved in movement of head from left to right.
NEET-PG 2019 - Anatomy NEET-PG Practice Questions and MCQs
Question 11: Joint involved in movement of head from left to right.
- A. Atlanto axial (Correct Answer)
- B. Atlanto occipital
- C. C2- C3 Joint
- D. C3- C4 Joint
Explanation: ***Atlanto axial*** - The **atlantoaxial joint** is responsible for the **rotation of the head**, allowing for movements such as shaking the head "no." - This joint is a **pivot joint** formed between the atlas (C1 vertebra) and the axis (C2 vertebra), specifically the **dens** of the axis articulating with the anterior arch of the atlas. *Atlanto occipital* - The **atlanto-occipital joint** primarily facilitates **flexion and extension of the head** (nodding "yes" movement). - This joint connects the **atlas (C1)** to the **occipital bone** of the skull. *C2- C3 Joint* - The **C2-C3 joint** is a typical **intervertebral joint** in the cervical spine. - While it contributes to overall cervical spine mobility, it does not primarily mediate the **rotational movement** of the head. *C3- C4 Joint* - The **C3-C4 joint** is another **intervertebral joint** in the cervical spine. - Its main roles include some degree of **flexion, extension, and lateral bending**, but it is not the primary joint for head rotation.
Biochemistry
1 questionsMenkes disease is caused by a deficiency of which protein?
NEET-PG 2019 - Biochemistry NEET-PG Practice Questions and MCQs
Question 11: Menkes disease is caused by a deficiency of which protein?
- A. ATP7B (Wilson disease protein)
- B. Ceruloplasmin
- C. Copper-zinc superoxide dismutase
- D. ATP7A (copper-transporting ATPase) (Correct Answer)
Explanation: ***ATP7A (copper-transporting ATPase)*** - **Menkes disease** is an X-linked recessive disorder caused by a mutation in the **ATP7A gene**, which encodes a copper-transporting ATPase. - This protein is essential for **copper absorption** from the intestines and its transport across cell membranes. *ATP7B (Wilson disease protein)* - Mutations in the **ATP7B gene** cause **Wilson disease**, characterized by **copper accumulation** in the liver, brain, and other organs due to impaired copper excretion. - Unlike Menkes disease, Wilson disease involves *too much* copper in tissues, not a deficiency due to poor absorption. *Ceruloplasmin* - **Ceruloplasmin** is a copper-carrying protein that transports copper in the blood and also acts as an oxidase. - While deficiencies in ceruloplasmin can lead to **aceruloplasminemia**, a disorder of iron metabolism, it is not the primary defect in Menkes disease. *Copper-zinc superoxide dismutase* - **Copper-zinc superoxide dismutase (SOD1)** is an enzyme that plays a crucial role in eliminating harmful **reactive oxygen species**. - Mutations in SOD1 are associated with some forms of **amyotrophic lateral sclerosis (ALS)**, not Menkes disease.
Internal Medicine
1 questionsWhat does a decreased FEV1/FVC ratio typically indicate in pulmonary function tests?
NEET-PG 2019 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 11: What does a decreased FEV1/FVC ratio typically indicate in pulmonary function tests?
- A. Normal pulmonary function
- B. Obstructive lung disease (Correct Answer)
- C. Restrictive lung disease
- D. Both obstructive and restrictive lung disease
Explanation: ***Obstructive lung disease*** - A decreased **FEV1/FVC ratio** indicates that the amount of air forcefully exhaled in one second (FEV1) is disproportionately low compared to the total forced vital capacity (FVC) [1]. This is a hallmark of **airflow limitation**, distinguishing obstructive lung diseases. - This pattern suggests a problem with **airway narrowing** or obstruction, making it difficult to exhale air quickly, which is characteristic of conditions like **COPD** (emphysema, chronic bronchitis) or **asthma** [1]. *Normal pulmonary function* - In normal pulmonary function, the **FEV1/FVC ratio** would be within the expected reference range, typically **above 70%** (or 0.7) for adults [1]. - A low ratio explicitly indicates a deviation from normal airflow dynamics, not a state of healthy lung function. *Restrictive lung disease* - **Restrictive lung diseases** are characterized by a **reduced total lung volume** (decreased FVC), but the FEV1/FVC ratio is typically **normal or even increased**. - This is because the airways are generally not obstructed; instead, the problem lies with the lungs' inability to expand fully, leading to a proportional reduction in FEV1 and FVC. *Both obstructive and restrictive lung disease* - While it is possible to have both conditions, a **decreased FEV1/FVC ratio** primarily points to an **obstructive pattern**. - A definitive diagnosis of both would require further interpretation of other PFT parameters such as **total lung capacity (TLC)**, which would be normal or increased in obstruction and reduced in restriction.
Microbiology
1 questionsRubella virus belongs to which family?
NEET-PG 2019 - Microbiology NEET-PG Practice Questions and MCQs
Question 11: Rubella virus belongs to which family?
- A. Orthomyxovirus
- B. Rheovirus
- C. Togavirus (Correct Answer)
- D. Picornavirus
Explanation: ***Togavirus*** - The **Rubella virus** is categorized under the family **Togaviridae**, specifically within the genus *Rubivirus*. - This classification is based on its genetic structure, being an **enveloped, positive-sense, single-stranded RNA virus**. *Rheovirus* - **Reoviruses** are characterized by a **double-stranded segmented RNA genome** and are typically non-enveloped. - This contrasts with Rubella's single-stranded, non-segmented RNA and enveloped structure. *Picornavirus* - **Picornaviruses** are a family of **non-enveloped, positive-sense, single-stranded RNA viruses** that are structurally different from Rubella. - Examples include species like **poliovirus** and **rhinovirus**, which do not share the distinct biological properties of Rubella. *Orthomyxovirus* - **Orthomyxoviruses** are a family of **enveloped, negative-sense, segmented RNA viruses**, which includes influenza viruses. - Their genomic organization and replication strategy are fundamentally different from those of the Rubella virus.
Pathology
1 questionsWhat are Gitter cells?
NEET-PG 2019 - Pathology NEET-PG Practice Questions and MCQs
Question 11: What are Gitter cells?
- A. Microglia
- B. Modified macrophages in the CNS (Correct Answer)
- C. Astrocytic cells
- D. Oligodendrocytic cells
Explanation: ***Modified macrophages in CNS*** - Gitter cells are **modified macrophages** that have phagocytized lipid and other debris in the central nervous system (CNS), particularly in response to injury or disease [1][2]. - They play a crucial role in **cleaning up cellular debris** and are involved in the inflammatory response within the CNS [2]. *Macroglia* - Macroglia refers to **supportive cells** in the CNS, including astrocytes and oligodendrocytes, rather than being specifically modified macrophages. - It does not specifically describe the **phagocytic role** characteristic of Gitter cells. *Oligodendrocytes* - Oligodendrocytes primarily function to **myelinate axons** in the CNS and do not possess the same phagocytic capabilities as Gitter cells. - They are involved in **insulation** of neuronal axons rather than debris clearance. *Astrocytes* - Astrocytes are the principal **supportive glial cells** in the CNS and do not exhibit the characteristics of Gitter cells. - Their functions include **maintaining blood-brain barrier**, regulating blood flow, and supporting neuronal metabolism, not phagocytosis. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Peripheral Nerves and Skeletal Muscles, pp. 1255-1256. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Manifestations Of Central And Peripheral Nervous System Disease, pp. 697-698.
Pharmacology
4 questionsWhich fluoroquinolone has the maximum bioavailability?
What is the drug of choice (DOC) for a scorpion sting bite?
Variation in sensitivity of response to different doses of a drug in different individuals is obtained from?
Which of the following drugs is used in SIADH?
NEET-PG 2019 - Pharmacology NEET-PG Practice Questions and MCQs
Question 11: Which fluoroquinolone has the maximum bioavailability?
- A. Gatifloxacin
- B. Ciprofloxacin
- C. Moxifloxacin
- D. Levofloxacin (Correct Answer)
Explanation: ***Levofloxacin*** - **Levofloxacin** exhibits high oral bioavailability, approximately 99%, meaning nearly all of the administered dose reaches systemic circulation [1]. - This high bioavailability allows for seamless transition from intravenous to oral administration without significant changes in drug exposure [1]. *Moxifloxacin* - **Moxifloxacin** has a high bioavailability of approximately 90%, which is slightly lower than levofloxacin's almost complete absorption [1]. - While excellent, it is not the absolute highest among fluoroquinolones. *Gatifloxacin* - **Gatifloxacin** has good oral bioavailability, around 96%, but it is still generally considered slightly less than that of levofloxacin [1]. - This difference, though small, makes levofloxacin the one with the highest overall bioavailability. *Ciprofloxacin* - **Ciprofloxacin** has the lowest oral bioavailability among the listed fluoroquinolones, ranging from 70% to 80% [1]. - Its absorption can be significantly impaired by co-administration with multivalent cations, leading to reduced systemic concentrations.
Question 12: What is the drug of choice (DOC) for a scorpion sting bite?
- A. EDTA
- B. Neostigmine
- C. N-acetylcysteine
- D. Prazosin (Correct Answer)
Explanation: ***Prazosin*** - **Prazosin** is an **alpha-1 adrenergic antagonist** that effectively counteracts the symptoms of scorpion envenomation, particularly **autonomic hyperactivity** like hypertension and tachycardia. - It works by blocking the effects of norepinephrine released by the scorpion venom, helping to stabilize vital signs and reduce cardiovascular complications. *EDTA* - **EDTA (ethylenediaminetetraacetic acid)** is a **chelating agent** primarily used to treat **heavy metal poisoning**, such as lead or mercury. - It binds to metal ions, forming a stable complex that can then be excreted from the body; it has no role in scorpion envenomation. *Neostigmine* - **Neostigmine** is an **acetylcholinesterase inhibitor** used to treat conditions like myasthenia gravis or to reverse the effects of neuromuscular blocking agents. - It increases acetylcholine levels at the neuromuscular junction; it is not indicated for the management of scorpion stings. *N-acetylcysteine* - **N-acetylcysteine (NAC)** is primarily used as an **antidote for acetaminophen overdose** and as a mucolytic agent in respiratory conditions. - It replenishes glutathione stores, helping to detoxify harmful metabolites; it has no direct role in treating scorpion venom effects.
Question 13: Variation in sensitivity of response to different doses of a drug in different individuals is obtained from?
- A. Dose-response relationship (Correct Answer)
- B. Therapeutic index
- C. Bioavailability
- D. Phase 1 clinical trials
Explanation: ***Dose-response relationship*** - The **dose-response relationship** (particularly the **graded dose-response curve**) describes how the magnitude of a drug's effect changes with different doses. - When plotted for different individuals or populations, these curves reveal **variation in sensitivity** through differences in potency (horizontal shift) and efficacy (maximum response). - This relationship helps characterize inter-individual variability in drug response and is the fundamental concept for understanding differential sensitivity. *Therapeutic index* - The **therapeutic index** is a measure of drug safety, representing the ratio between the toxic dose and the effective dose (TD50/ED50 or LD50/ED50). - It does not directly explain the variation in sensitivity to different doses among individuals, but rather provides information about the drug's overall safety margin. *Bioavailability* - **Bioavailability** refers to the fraction of an administered drug that reaches the systemic circulation unchanged. - While it influences the drug concentration at the site of action, it doesn't directly measure the variability in physiological response to that concentration among individuals. *Phase 1 clinical trials* - **Phase 1 clinical trials** are the first stage of testing a new drug in humans, primarily focusing on safety, dosage range, and pharmacokinetics in a small group of healthy volunteers. - While variability in response may be observed during these trials, they are not the *pharmacological concept* that describes this variation; rather, dose-response relationships are used to interpret findings from these trials.
Question 14: Which of the following drugs is used in SIADH?
- A. Desmopressin
- B. Terlipressin
- C. Tolvaptan (Correct Answer)
- D. Von Willebrand factor
Explanation: ***Tolvaptan*** - **Tolvaptan** is a **vasopressin receptor antagonist** that blocks the action of **antidiuretic hormone (ADH)** at the **V2 receptors** in the kidneys [1]. - This action promotes **water excretion (aquaresis)** without significantly affecting electrolyte balance, thereby increasing serum sodium levels in patients with **SIADH** [1]. *Desmopressin* - **Desmopressin** is a synthetic analog of **ADH** that primarily acts on **V2 receptors**, promoting water reabsorption [3], [4]. - It is used in conditions like **diabetes insipidus** [3], [4] or **hemophilia** [2] to increase ADH activity or clotting factors, which is contrary to the goal in SIADH. *Von Willebrand factor* - **Von Willebrand factor** is a **glycoprotein** involved in **hemostasis**, promoting platelet adhesion and carrying **factor VIII**. - It plays no role in the direct management of **SIADH** or fluid balance disorders. *Terlipressin* - **Terlipressin** is an analog of **vasopressin** that primarily acts on **V1 receptors**, causing vasoconstriction [5]. - It is used in conditions like **hepatorenal syndrome** or **esophageal variceal bleeding**, not for treating **SIADH**.
Physiology
1 questionsTubuloglomerular feedback control is useful for which one of the following?
NEET-PG 2019 - Physiology NEET-PG Practice Questions and MCQs
Question 11: Tubuloglomerular feedback control is useful for which one of the following?
- A. GFR (Correct Answer)
- B. Plasma sodium
- C. Plasma volume
- D. Determining tubular secretion
Explanation: ***GFR*** - **Tubuloglomerular feedback (TGF)** is a critical autoregulatory mechanism that maintains a relatively constant **glomerular filtration rate (GFR)** despite fluctuations in arterial blood pressure. - The **macula densa** cells at the end of the thick ascending limb of the loop of Henle sense the **volume** and **sodium chloride concentration** of the tubular fluid and release paracrine factors to adjust afferent arteriolar resistance. *Plasma sodium* - While TGF senses the **sodium chloride concentration** in the filtrate, its primary role is to regulate GFR, not directly control systemic plasma sodium levels. - Plasma sodium is primarily regulated by hormones like **ADH** and **aldosterone**, which influence water reabsorption and sodium excretion. *Plasma volume* - **Plasma volume** is regulated predominantly by hormonal mechanisms (e.g., **renin-angiotensin-aldosterone system**, **ADH**, **ANP**) and control over overall sodium and water balance, rather than by the acute, intrinsic GFR regulation of TGF. - Changes in plasma volume can indirectly affect GFR, but TGF is not the direct control mechanism for plasma volume itself. *Determining tubular secretion* - **Tubular secretion** is the process by which solutes are actively transported from the peritubular capillaries into the tubular lumen. - TGF influences **glomerular filtration**, not directly the rates of tubular secretion, which are regulated by specific transport proteins and physiological needs.