Anatomy
1 questionsWhich of the following structures pass through the superior orbital fissure?
NEET-PG 2013 - Anatomy NEET-PG Practice Questions and MCQs
Question 121: Which of the following structures pass through the superior orbital fissure?
- A. Oculomotor nerve
- B. Trochlear nerve
- C. Superior ophthalmic vein
- D. All of the options (Correct Answer)
Explanation: ***All of the options*** - The **superior orbital fissure** is a key opening in the skull that allows passage of several important cranial nerves and vessels into the orbit. - The **oculomotor nerve**, **trochlear nerve**, and **superior ophthalmic vein** are all established structures that pass through this fissure. *Oculomotor nerve* - The **oculomotor nerve (CN III)** passes through the superior orbital fissure to innervate most of the extrinsic eye muscles. - It controls movements such as **adduction**, **elevation**, and **depression** of the eyeball, and also innervates the **levator palpebrae superioris** muscle for eyelid elevation [1]. *Trochlear nerve* - The **trochlear nerve (CN IV)**, which innervates the **superior oblique muscle**, also passes through the superior orbital fissure. - The superior oblique muscle is responsible for **intorsion** and **depression** of the eye, particularly when the eye is adducted [1]. *Superior ophthalmic vein* - The **superior ophthalmic vein** drains blood from structures within the orbit and passes through the superior orbital fissure to drain into the **cavernous sinus**. - This vein provides a connection between the facial veins and the cavernous sinus, which can be clinically relevant in cases of infection spread.
Biochemistry
1 questionsWhich protein hormone is often referred to as the 'guardian angel against obesity' due to its role in regulating metabolism?
NEET-PG 2013 - Biochemistry NEET-PG Practice Questions and MCQs
Question 121: Which protein hormone is often referred to as the 'guardian angel against obesity' due to its role in regulating metabolism?
- A. Adiponectin (Correct Answer)
- B. Fibronectin
- C. High-Density Lipoprotein (HDL)
- D. Insulin
Explanation: ***Adiponectin*** - **Adiponectin** is a hormone secreted by **adipose tissue** that plays a crucial role in regulating glucose and fatty acid metabolism, increasing **insulin sensitivity**, and decreasing inflammation. - Its levels are inversely correlated with body fat percentage; individuals with obesity tend to have lower adiponectin levels, leading to its nickname as the 'guardian angel against obesity'. *Fibronectin* - **Fibronectin** is a glycoprotein involved in cell adhesion, growth, migration, and differentiation, and is a key component of the **extracellular matrix**. - It does not primarily function in metabolic regulation or body weight control, unlike adiponectin. *High-Density Lipoprotein (HDL)* - **HDL** is a type of lipoprotein that transports cholesterol from peripheral tissues back to the liver, a process known as **reverse cholesterol transport**. - While beneficial for cardiovascular health, HDL is a lipid-carrying particle, not a protein hormone, and its primary role is not in metabolic regulation or direct obesity prevention. *Insulin* - **Insulin** is a peptide hormone produced by the pancreas that regulates carbohydrate and fat metabolism, primarily by facilitating glucose uptake from the blood into cells. - While essential for metabolism, high levels of insulin in the context of insulin resistance can contribute to obesity, rather than act against it.
Internal Medicine
1 questionsWhich one of the following is the most common CNS tumor associated with type I neurofibromatosis?
NEET-PG 2013 - Internal Medicine NEET-PG Practice Questions and MCQs
Question 121: Which one of the following is the most common CNS tumor associated with type I neurofibromatosis?
- A. Optic nerve glioma (Correct Answer)
- B. Meningioma
- C. Acoustic schwannoma
- D. Low grade astrocytoma
Explanation: ***Optic nerve glioma*** - **Optic nerve gliomas** are the most frequently encountered central nervous system tumors in patients with **Type 1 neurofibromatosis (NF1)**, occurring in about 15% of individuals. - They are typically low-grade **astrocytomas** and can cause vision loss and proptosis depending on their size and location. *Meningioma* - While more common in **Type 2 neurofibromatosis (NF2)**, meningiomas can occur in NF1, but are not the most common CNS tumor. - Meningiomas are tumors that arise from the **meninges**, the membranes surrounding the brain and spinal cord. *Acoustic schwannoma* - **Bilateral acoustic schwannomas (vestibular schwannomas)** are the hallmark feature of **Type 2 neurofibromatosis (NF2)**, not NF1 [1]. - These tumors arise from the Schwann cells of the **vestibulocochlear nerve** and can cause hearing loss and balance issues [1]. *Low grade astrocytoma* - While optic nerve gliomas are a type of low-grade astrocytoma, this option is too general; **optic nerve glioma** is the specific and most common presentation in NF1. - Other forms of low-grade astrocytomas can occur in NF1 but are not as universally characteristic as optic nerve gliomas.
Pharmacology
5 questionsWhich route of administration undergoes the maximum first pass metabolism?
Which of the following drugs is used for Smoking Cessation?
In the context of pharmacology, which plasma protein do acidic drugs primarily bind to?
Which drug has the highest plasma protein binding?
What is the mechanism of metabolism for alcohol, aspirin, and phenytoin at high doses?
NEET-PG 2013 - Pharmacology NEET-PG Practice Questions and MCQs
Question 121: Which route of administration undergoes the maximum first pass metabolism?
- A. Intra-arterial
- B. Rectal
- C. Oral (Correct Answer)
- D. Intravenous
Explanation: ***Oral*** - Drugs administered orally are absorbed from the **gastrointestinal tract** and transported via the **portal vein** directly to the liver, where they undergo significant **first-pass metabolism** before reaching systemic circulation. - This hepatic metabolism can drastically reduce the **bioavailability** of the drug, requiring higher doses or alternative administration routes. *Intra-arterial* - This route delivers drugs directly into an **artery** supplying a target tissue or organ, largely bypassing systemic circulation and initial hepatic metabolism. - It is used for localized effects, such as **chemotherapy** for specific tumors, minimizing systemic exposure. *Rectal* - While a portion of rectally administered drugs may bypass the portal circulation by entering the **inferior and middle rectal veins**, a significant amount can still be absorbed into the superior rectal vein, which drains into the portal system. - This means rectal administration offers only **partial avoidance** of first-pass metabolism, making it less complete than IV or intra-arterial routes for bypassing the liver altogether. *Intravenous* - Drugs administered intravenously are delivered directly into the **systemic circulation**, completely bypassing the gastrointestinal tract and the liver's first-pass metabolism. - This route ensures **100% bioavailability** and rapid onset of action, as the drug immediately reaches its target.
Question 122: Which of the following drugs is used for Smoking Cessation?
- A. Bupropion (Correct Answer)
- B. Methadone
- C. Buprenorphine
- D. Naltrexone
Explanation: ***Bupropion*** - **Bupropion** is an antidepressant that is also approved as a smoking cessation aid. It works by inhibiting the reuptake of **dopamine** and **norepinephrine**, which can help reduce nicotine cravings and withdrawal symptoms. - It is often prescribed as a first-line pharmacotherapy for smoking cessation, with a typical treatment duration of 7-12 weeks. *Buprenorphine* - **Buprenorphine** is a partial opioid agonist primarily used to treat opioid addiction. It is not indicated for smoking cessation. - While it can help manage withdrawal symptoms from opioids, it has no direct mechanism of action that would reduce nicotine dependence or cravings. *Methadone* - **Methadone** is a full opioid agonist primarily used for the treatment of opioid use disorder (OUD) and chronic pain management. It is not used for smoking cessation. - Its mechanism involves binding to opioid receptors to prevent withdrawal symptoms and reduce cravings for other opioids. *Naltrexone* - **Naltrexone** is an opioid antagonist used primarily for the treatment of alcohol dependence and opioid use disorder. It is not indicated for smoking cessation. - It blocks the effects of opioids and reduces alcohol cravings, but does not affect nicotine pathways or dependence.
Question 123: In the context of pharmacology, which plasma protein do acidic drugs primarily bind to?
- A. Globulin
- B. Albumin (Correct Answer)
- C. α1-acid glycoprotein
- D. None of the options
Explanation: ***Albumin*** - **Albumin** is the most abundant plasma protein and has multiple binding sites for a wide range of drugs, particularly **acidic drugs**. - Its high concentration and diverse binding capabilities make it the primary transporter for many **lipophilic** and **anionic drugs**. *Globulin* - **Globulins** are a diverse group of proteins, some of which bind to drugs, but they primarily transport **hormones**, **metals**, and **vitamins**, not acidic drugs. - They are less significant for binding acidic drugs compared to albumin. *α1-acid glycoprotein* - **α1-acid glycoprotein** primarily binds to **basic drugs** due to its numerous acidic residues. - While it plays a crucial role in binding basic compounds, it has limited affinity for acidic drugs. *None of the options* - This option is incorrect because **albumin** is a well-established and significant plasma protein for binding acidic drugs. - Specific plasma proteins are known to bind different types of drugs, and for acidic drugs, albumin is the primary binder.
Question 124: Which drug has the highest plasma protein binding?
- A. Warfarin (Correct Answer)
- B. Verapamil
- C. Aspirin
- D. GTN
Explanation: ***Warfarin*** - **Warfarin** exhibits very **high plasma protein binding**, typically greater than 99%, primarily to albumin. - This high binding capacity means that only a small fraction of the drug is free and pharmacologically active. - Due to high protein binding, warfarin is susceptible to drug interactions when displaced from albumin. *Verapamil* - **Verapamil** has a relatively high plasma protein binding, around 90%, but it is not as high as warfarin. - Its binding is predominantly to **albumin** and alpha-1-acid glycoprotein. *Aspirin* - **Aspirin** (acetylsalicylic acid) has moderate plasma protein binding, usually between 50-90%, depending on the dosage. - It binds to **albumin** and can displace other protein-bound drugs. *GTN* - **Glyceryl trinitrate (GTN)** has moderate plasma protein binding, approximately 60%. - Its rapid onset and short duration of action are primarily due to its extensive first-pass metabolism and quick redistribution, rather than protein binding characteristics.
Question 125: What is the mechanism of metabolism for alcohol, aspirin, and phenytoin at high doses?
- A. First pass kinetics
- B. First order kinetics
- C. Zero order kinetics (Correct Answer)
- D. Second order kinetics
Explanation: ***Zero order kinetics*** - This mechanism occurs when the **metabolic enzymes become saturated at high drug concentrations**, leading to a constant amount (not a constant percentage) of drug being eliminated per unit time. - Alcohol, aspirin, and phenytoin are examples of drugs that exhibit **saturable metabolism**, transitioning from first-order to zero-order kinetics at higher doses. *First pass kinetics* - This describes the **metabolism of a drug by the liver or gut wall enzymes before it reaches systemic circulation** after oral administration. - While relevant to the oral bioavailability of these drugs, it does not describe the specific mechanism of elimination at high doses. *First order kinetics* - In this mechanism, a **constant fraction or percentage of the drug is eliminated per unit of time**, meaning the rate of elimination is directly proportional to the drug concentration. - Most drugs follow first-order kinetics at therapeutic doses because metabolizing enzymes are not saturated. *Second order kinetics* - This is a **less common pharmacokinetic model** where the rate of elimination is proportional to the square of the drug concentration or involves two reactants. - It does not typically describe the common elimination patterns of most drugs, including alcohol, aspirin, and phenytoin.
Psychiatry
1 questionsWhich of the following develop first during dependence of a substance ?
NEET-PG 2013 - Psychiatry NEET-PG Practice Questions and MCQs
Question 121: Which of the following develop first during dependence of a substance ?
- A. Tolerance
- B. Physical dependence
- C. Psychological dependence (Correct Answer)
- D. Withdrawal symptoms
Explanation: ***Psychological dependence*** - **Psychological dependence** often develops first, characterized by an emotional need for the substance to experience pleasure or avoid discomfort. - This involves a strong **craving** and compulsive drug-seeking behavior despite negative consequences, driven by the substance's effect on brain reward pathways. *Tolerance* - **Tolerance** means that increasing doses of the substance are required to achieve the same effect previously achieved with lower doses. - While it often develops early in substance use, the initial "need" to use the substance is often psychological before physiological adaptations occur. *Physical dependence* - **Physical dependence** describes the body's physiological adaptation to the substance, leading to withdrawal symptoms if use is stopped or reduced. - It typically develops after consistent, prolonged use and is usually preceded by psychological dependence and often tolerance. *Withdrawal symptoms* - **Withdrawal symptoms** are the physiological and psychological signs that occur when a dependent person stops or drastically reduces their substance intake. - These are a direct manifestation of physical dependence and thus develop once physical dependence has been established.
Surgery
1 questionsWhich condition typically presents with irregular, hard palpable masses in the breast?
NEET-PG 2013 - Surgery NEET-PG Practice Questions and MCQs
Question 121: Which condition typically presents with irregular, hard palpable masses in the breast?
- A. Non comedo DCIS
- B. Fibroadenoma
- C. Invasive ductal carcinoma (Correct Answer)
- D. Comedocarcinoma
Explanation: ***Paget's disease*** - Paget's disease of the breast leads to **palpable abnormalities** such as skin changes and underlying mass formation [1]. - Often presents with **nipple discharge** and alterations in the areola, indicating an underlying malignancy [2]. *Non comedo DCIS* - Non comedo ductal carcinoma in situ (DCIS) typically presents with **microscopic changes** and lacks palpable masses. - Frequently asymptomatic and may not cause any **significant clinical findings** or changes in the breast. *None* - This option suggests the absence of a related condition, which does not address the query about a type of DCIS causing a **palpable abnormality**. - In the context of DCIS, there are sure conditions (like Paget's) that **do cause palpable changes**. *Comedocarcinoma* - This type of DCIS is characterized by **necrosis and calcifications**, rather than a palpable mass. - While potentially aggressive, it usually does not present with noticeable **palpable abnormalities** like Paget's disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Breast, pp. 1061-1062. [2] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Liver And Biliary System Disease, pp. 456-457.