Anatomy
2 questionsWhich of these best describes the renal angle?
Which of the following is NOT a surface marking of the oblique fissure of the lung?
NEET-PG 2012 - Anatomy NEET-PG Practice Questions and MCQs
Question 301: Which of these best describes the renal angle?
- A. The angle between the latissimus dorsi and the 12th rib
- B. The angle between the erector spinae and the iliac crest
- C. The angle between the 12th rib and the erector spinae (Correct Answer)
- D. The angle between the 12th rib and the rectus abdominis
Explanation: ***The angle between the 12th rib and the erector spinae*** - The **renal angle** (also known as the costovertebral angle) is the space formed by the junction of the **12th rib** and the **erector spinae muscles** laterally. - This anatomical landmark is clinically significant for assessing **kidney pain** or inflammation (e.g., in pyelonephritis) through percussion. *The angle between the latissimus dorsi and the 12th rib* - While the **latissimus dorsi** is a significant back muscle, it is not the primary anatomical landmark that defines the renal angle. - The renal angle specifically refers to the relationship between the rib cage and the deeper spinal muscles. *The angle between the erector spinae and the iliac crest* - This description refers to a region lower down on the back, closer to the **pelvis**, and not directly related to the position of the kidneys. - The **iliac crest** defines the upper border of the pelvis, far from the kidney's typical location relative to the 12th rib. *The angle between the 12th rib and the rectus abdominis* - The **rectus abdominis** muscle is located on the anterior (front) aspect of the abdomen, involved in trunk flexion. - This muscle is anatomically distinct and separate from the posterior flank region where the kidneys are located and where the renal angle is assessed.
Question 302: Which of the following is NOT a surface marking of the oblique fissure of the lung?
- A. 6th costal cartilage
- B. T3
- C. 5th rib
- D. 7th rib (Correct Answer)
Explanation: ***7th rib*** - The **oblique fissure** typically extends from the spine at approximately the **T3 vertebral level** anteriorly to the **6th costal cartilage**. [1] - The **7th rib** is generally inferior to the typical anterior termination point of the oblique fissure. [1] *T3* - The **oblique fissure** begins posteriorly at the level of the **spinous process of T3**. [1] - This marks the superior-posterior extent of the fissure on the surface. *5th rib* - The **oblique fissure** crosses the **5th intercostal space** on the lateral chest wall. [1] - This point helps map the fissure's path between its posterior and anterior endpoints. *6th costal cartilage* - The **oblique fissure** terminates anteriorly near the **6th costal cartilage** in the midclavicular line. [1] - This represents the inferior-anterior most point of the fissure on the chest wall.
Anesthesiology
1 questionsWhich of the following is true about coeliac plexus block?
NEET-PG 2012 - Anesthesiology NEET-PG Practice Questions and MCQs
Question 301: Which of the following is true about coeliac plexus block?
- A. Usually done unilaterally
- B. Most common side effects include diarrhea and hypotension (Correct Answer)
- C. Located retroperitoneally at the level of L3
- D. Useful for painful conditions of the lower abdomen
Explanation: ***Most common side effects include diarrhea and hypotension*** - A coeliac plexus block interrupts **sympathetic innervation** to the upper abdominal organs, which can lead to parasympathetic dominance. - This imbalance often results in **increased gastrointestinal motility (diarrhea)** and **vasodilation (hypotension)** as common side effects. *Located retroperitoneally at the level of L3* - The coeliac plexus is typically located **retroperitoneally** at the level of the **T12-L1 vertebrae**, not L3. - Its position is generally superior to the renal arteries, which are closer to L1-L2. *Usually done unilaterally* - A coeliac plexus block is almost always performed **bilaterally** or with a single posterior approach aiming for bilateral spread to effectively block the plexus. - The coeliac plexus is an extensive network, and a unilateral block would likely provide inadequate pain relief. *Useful for painful conditions of the lower abdomen* - The coeliac plexus primarily innervates **upper abdominal organs** (e.g., pancreas, liver, stomach, small intestine, kidneys, adrenal glands). - It is therefore generally **ineffective for lower abdominal pain**, which is innervated by different sympathetic plexuses (e.g., superior and inferior hypogastric plexuses).
Biochemistry
1 questionsWhat cofactor is required for the proper functioning of glucose-6-phosphate dehydrogenase?
NEET-PG 2012 - Biochemistry NEET-PG Practice Questions and MCQs
Question 301: What cofactor is required for the proper functioning of glucose-6-phosphate dehydrogenase?
- A. NAD
- B. NADP (Correct Answer)
- C. FAD
- D. FMN
Explanation: ***NADP*** - **NADP+** (nicotinamide adenine dinucleotide phosphate) acts as the **electron acceptor** in the **glucose-6-phosphate dehydrogenase (G6PD)** reaction, becoming **NADPH**. - **NADPH** is crucial for maintaining the **redox balance** in cells, particularly in red blood cells, by reducing **oxidative stress**. *NAD* - **NAD+** (nicotinamide adenine dinucleotide) is a primary cofactor for many **dehydrogenase reactions** in catabolic pathways like **glycolysis** and the **Krebs cycle**. - It primarily functions as an electron acceptor in pathways that generate **ATP**, distinct from the role of **NADPH** in reductive biosynthesis and antioxidant defense. *FAD* - **FAD** (flavin adenine dinucleotide) is a coenzyme derived from **riboflavin (vitamin B2)** that is involved in various redox reactions, often in the form of **flavoproteins**. - Enzymes like **succinate dehydrogenase** in the electron transport chain utilize **FAD** as an electron acceptor, which is not the case for G6PD. *FMN* - **FMN** (flavin mononucleotide) is another coenzyme derived from **riboflavin**, structurally similar to FAD but lacking the additional adenosine monophosphate. - It participates in electron transfer reactions, particularly within **complex I** of the **electron transport chain**, but is not a cofactor for G6PD.
Physiology
6 questionsLesion of preoptic nucleus of hypothalamus is associated with which of the following conditions?
Transpulmonary pressure is the difference between:
What happens to the concentration of inulin as fluid passes through the Proximal Convoluted Tubule (PCT)?
What is the duration of the second heart sound (S2)?
What is the primary factor that determines the resting membrane potential in a nerve fiber?
Which tract is responsible for the loss of proprioception and fine touch?
NEET-PG 2012 - Physiology NEET-PG Practice Questions and MCQs
Question 301: Lesion of preoptic nucleus of hypothalamus is associated with which of the following conditions?
- A. Impaired thermoregulation
- B. Increased body temperature
- C. Hyperthermia (Correct Answer)
- D. Normal thermoregulation
Explanation: ***Hyperthermia*** - The **preoptic nucleus** of the anterior hypothalamus is the primary **heat-loss center** containing warm-sensitive neurons. - Lesion of this area impairs **heat dissipation mechanisms** (sweating, cutaneous vasodilation), preventing the body from lowering its temperature. - Results in **hyperthermia** - a pathological elevation of core body temperature due to failure of heat dissipation, not a change in set point. - This is the **most specific and clinically accurate** term for this condition. *Impaired thermoregulation* - While technically true, this is too **broad and non-specific**. - Impaired thermoregulation could refer to inability to either increase or decrease temperature. - In medical terminology, we use more specific terms like "hyperthermia" to describe the actual clinical condition. *Increased body temperature* - This is a **general descriptive term** rather than a specific clinical diagnosis. - While the body temperature is indeed increased, **hyperthermia** is the precise medical term that indicates the mechanism (impaired heat dissipation). - Less specific than "hyperthermia" for exam purposes. *Normal thermoregulation* - Clearly incorrect - a lesion in the primary thermoregulatory center would **abolish normal temperature control**. - The preoptic nucleus is essential for detecting and responding to temperature changes.
Question 302: Transpulmonary pressure is the difference between:
- A. Pressure in alveoli and intrapleural pressure (Correct Answer)
- B. The pressure in the bronchus and atmospheric pressure
- C. The difference between atmospheric pressure and intrapleural pressure
- D. The difference between atmospheric pressure and intraalveolar pressure
Explanation: ***Pressure in alveoli and intrapleural pressure*** - Transpulmonary pressure is the **pressure gradient** across the lung wall, which is essential for maintaining alveolar inflation. - It is calculated as the **alveolar pressure minus the intrapleural pressure**. *The pressure in the bronchus and atmospheric pressure* - This difference would represent the pressure driving airflow through the **bronchial tree**, not the pressure across the lung wall itself. - It's a measure relevant to **airway resistance**, not lung distension. *The difference between atmospheric pressure and intrapleural pressure* - This difference is related to the **intrathoracic pressure**, which influences venous return and cardiac function, but not directly the distension of the lungs. - It does not account for the **alveolar pressure**, which is the primary internal pressure expanding the lung. *The difference between atmospheric pressure and intraalveolar pressure* - This difference is the **driving pressure for airflow** into or out of the lungs. - It represents the pressure gradient that causes air to move between the **atmosphere and the alveoli** during inspiration and expiration.
Question 303: What happens to the concentration of inulin as fluid passes through the Proximal Convoluted Tubule (PCT)?
- A. Concentration of inulin increases (Correct Answer)
- B. Concentration of urea remains constant
- C. Concentration of HCO3- increases
- D. Concentration of Na+ decreases
Explanation: ***Concentration of inulin increases*** - Inulin is **freely filtered** at the glomerulus and is neither reabsorbed nor secreted along the renal tubule, making it an excellent marker for **glomerular filtration rate (GFR)**. - As water is reabsorbed from the PCT, the volume of tubular fluid decreases, causing the concentration of **unreabsorbed solutes**, like inulin, to increase. *Concentration of urea remains constant* - Urea is **reabsorbed** along the tubule, though passively; its concentration typically **increases** initially in the PCT due to water reabsorption, but then decreases as some is reabsorbed. - The statement is incorrect because urea concentration changes significantly throughout the nephron, particularly increasing as water is reabsorbed and then decreasing with some reabsorption. *Concentration of HCO3- increases* - The majority (approximately 80-90%) of **bicarbonate (HCO3-)** is reabsorbed in the PCT, primarily through its conversion to CO2 within the tubular lumen and then back to HCO3- intracellularly. - Therefore, the concentration of HCO3- in the tubular fluid actually **decreases** significantly as fluid passes through the PCT. *Concentration of Na+ decreases* - **Sodium (Na+)** is actively reabsorbed along the entire nephron, with about 65-70% reabsorbed in the PCT. - While Na+ is reabsorbed, water follows passively, so its concentration in the tubular fluid remains relatively **iso-osmotic** with plasma, meaning its concentration does not significantly decrease as fluid passes through the PCT, remaining fairly constant.
Question 304: What is the duration of the second heart sound (S2)?
- A. 0.15 sec
- B. 0.1 sec
- C. 0.12 sec
- D. 0.08 sec (Correct Answer)
Explanation: ***0.08 sec*** - The second heart sound (S2) is composed of two components: A2 (aortic valve closure) and P2 (pulmonic valve closure). The normal duration of S2, encompassing both components, is approximately **0.08 seconds**. - This short duration reflects the rapid closure of the aortic and pulmonic valves at the beginning of **diastole**. *0.15sec* - A duration of **0.15 seconds** for S2 is significantly longer than normal, which could indicate abnormal valve function or conditions causing delayed valve closure. - Such prolonged duration might be observed in conditions like **severe pulmonic stenosis** or **pulmonic hypertension**, which are not the typical duration of a healthy S2. *0.12 sec* - A duration of **0.12 seconds** is also longer than the typical normal range for S2. - While still shorter than 0.15 seconds, it could suggest subtle delays in valve closure or splitting that exceeds the usual physiological splitting. *0.1 sec* - A duration of **0.1 seconds** is slightly prolonged but generally falls within a range that might be considered borderline or indicative of minimal physiological variations. - However, in typical healthy individuals, the S2 duration is closer to 0.08 seconds, making 0.1 seconds less precise for the most common duration.
Question 305: What is the primary factor that determines the resting membrane potential in a nerve fiber?
- A. Is equal to the resting potential of cardiac muscle fibers.
- B. Can be accurately measured using intracellular electrodes.
- C. Increases with elevated extracellular potassium concentration.
- D. Is primarily determined by the equilibrium potential of potassium ions. (Correct Answer)
Explanation: ***Is primarily determined by the equilibrium potential of potassium ions*** - The **resting membrane potential** of a nerve fiber is predominantly set by the efflux of **potassium ions** through leak channels, bringing the membrane potential close to potassium's equilibrium potential. - The high permeability of the nerve membrane to **potassium** at rest means that K+ movement is the most significant factor influencing the potential. *Is equal to the resting potential of cardiac muscle fibers* - **Cardiac muscle fibers** have a distinct resting potential (around -80 to -90 mV) influenced by different ion channels and regulatory mechanisms compared to nerve fibers (around -70 mV). - While both involve potassium currents, their specific conductances and the contribution of other ions differ significantly. *Can be accurately measured using intracellular electrodes* - While **intracellular electrodes** are indeed used to measure the resting membrane potential, this statement describes a measurement method, not the *primary factor* that determines the potential itself. - The method of measurement does not explain the underlying biophysical mechanisms that establish the potential. *Increases with elevated extracellular potassium concentration* - An **elevated extracellular potassium concentration** would make the resting membrane potential *less negative* (depolarize) rather than "increase" it in the typical sense of a more positive value. - This is because a higher external K+ reduces the concentration gradient for potassium efflux, bringing the membrane potential closer to zero.
Question 306: Which tract is responsible for the loss of proprioception and fine touch?
- A. Anterior spinothalamic tract
- B. Lateral spinothalamic tract
- C. Dorsal column (Correct Answer)
- D. Corticospinal tract
Explanation: ***Dorsal column*** - The **dorsal column-medial lemniscus pathway** is responsible for transmitting **fine touch**, **vibration**, and **proprioception** from the body to the cerebral cortex. - Damage to this tract (e.g., in **tabes dorsalis** or **vitamin B12 deficiency**) leads to a loss of these sensations. *Anterior spinothalamic tract* - This tract primarily conveys crude touch and pressure sensations. - While it carries tactile information, it does not transmit the fine discriminative touch or proprioception associated with the dorsal columns. *Lateral spinothalamic tract* - This pathway is responsible for transmitting **pain** and **temperature** sensations. - It does not play a role in proprioception or fine touch. *Corticospinal tract* - The **corticospinal tract** is a **motor pathway** responsible for voluntary movement. - It has no role in transmitting sensory information such as proprioception or fine touch.