NEET-PG 2013 Practice Questions

Q: Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?

Extensor Carpi Radialis Brevis. Extensor Carpi Radialis Brevis - The radial nerve travels in the spiral groove of the humerus and gives off branches in a specific sequence. - Proximal to the spiral groove: Branches to triceps and anconeus - Within/at the spiral groove: Branches to brachioradialis and extensor carpi radialis longus (ECRL) - Just distal to the spiral groove: Branch to extensor carpi radialis brevis (ECRB) [1] - this is the first branch after exiting the spiral groove - More distally: The nerve divides into superficial and deep branches (posterior interosseous nerve) [1] - An injury just below the spiral groove would paralyze ECRB while sparing muscles innervated proximal to or within the groove (triceps, anconeus, brachioradialis, ECRL). Supinator - The supinator is innervated by the deep branch of the radial nerve (posterior interosseous nerve), which branches off more distally in the proximal forearm. - This muscle would only be affected by injuries distal to the bifurcation of the radial nerve into superficial and deep branches, not by an injury just below the spiral groove. Extensor Digitorum - The extensor digitorum is supplied by the posterior interosseous nerve, which is a continuation of the deep branch [1]. - This innervation occurs significantly distal to the spiral groove in the posterior forearm compartment. - It would be affected by posterior interosseous nerve injuries, not by lesions just below the spiral groove. Abductor Pollicis Longus - The abductor pollicis longus is innervated by the posterior interosseous nerve in the distal forearm [1]. - This is the most distal of all the options and would only be affected by posterior interosseous nerve palsy, not by radial nerve injury at the spiral groove level [1].

Q: Which nucleus is primarily involved in the Papez circuit?

Anterior nucleus of the thalamus. ***Anterior nucleus of the thalamus*** - The **anterior nucleus of the thalamus** is a key relay station in the Papez circuit [1], receiving input from the mamillary bodies and projecting to the cingulate gyrus. - This circuit is crucial for **memory formation** [2] and emotional processing. *Pulvinar nucleus* - The pulvinar nucleus is primarily involved in **visual processing**, attention, and eye movements. - It does not form a direct part of the classic Papez circuit for emotion and memory. *Intralaminar nucleus* - The intralaminar nuclei are involved in **arousal**, attention, and pain perception, with widespread projections to the cerebral cortex [1]. - They are not considered a primary component of the Papez circuit. *Ventral posterolateral (VPL) nucleus* - The VPL nucleus is a major **somatosensory relay** in the thalamus, transmitting touch, proprioception, and vibration information from the body to the cortex. - It has no direct role in the Papez circuit or limbic functions.

Q: Which of the following is the major glycosaminoglycan of synovial fluid?

Hyaluronic acid. ***Hyaluronic acid*** - **Hyaluronic acid** is the primary glycosaminoglycan in **synovial fluid**, providing its characteristic **viscosity** and **lubricating properties**. - It plays a crucial role in maintaining **joint health** by reducing friction and acting as a shock absorber. *Chondroitin sulfate* - **Chondroitin sulfate** is abundant in **cartilage**, contributing to its **compressive strength**. - While present in connective tissues, it is not the major glycosaminoglycan of synovial fluid. *Dermatan sulfate* - **Dermatan sulfate** is primarily found in **skin**, **blood vessels**, and **heart valves**. - Its main roles involve tissue structure and repair, not lubrication of synovial fluid. *Heparan sulfate* - **Heparan sulfate** is found on **cell surfaces** and in the **extracellular matrix**, especially in the **basement membranes**. - It regulates cell growth, adhesion, and signaling, and is not a major component of synovial fluid viscosity.

Q: Which organelle produces and destroys H2O2?

Peroxisome. ***Peroxisome*** - **Peroxisomes** are organelles that both produce and break down **hydrogen peroxide (H2O2)** during metabolic processes. - They contain **oxidases** (such as D-amino acid oxidase and urate oxidase) that produce H2O2 as a byproduct during oxidation reactions. - They also contain the enzyme **catalase** that converts H2O2 into water and oxygen, protecting the cell from oxidative damage. - This dual function makes peroxisomes unique in H2O2 metabolism. *Lysosome* - **Lysosomes** are responsible for breaking down waste materials and cellular debris through **hydrolytic enzymes**. - They are primarily involved in **cellular digestion** and waste removal, not H2O2 metabolism. *Golgi body* - The **Golgi apparatus** modifies, sorts, and packages proteins and lipids for secretion or delivery to other organelles. - It is crucial for **protein trafficking** and glycosylation, but does not produce or destroy H2O2. *Ribosome* - **Ribosomes** are responsible for **protein synthesis** (translation) based on genetic information carried by mRNA. - They are involved in the assembly of amino acids into proteins, not the metabolism of hydrogen peroxide.

Q: Which of the following is a non- modifiable risk factor for CHD -

Old age. Old age - Age is a **non-modifiable risk factor** for Coronary Heart Disease (CHD) because it is an inherent biological process that cannot be changed [3]. - The risk of developing CHD **increases with age** due to cumulative exposure to other risk factors and natural wear and tear on the cardiovascular system [3]. *Diabetes* - Diabetes is a **modifiable risk factor** for CHD because it can be managed and controlled through lifestyle changes, medication, and regular monitoring [2]. - **Poorly controlled diabetes** significantly increases the risk of heart disease by damaging blood vessels and promoting atherosclerosis. *Smoking* - Smoking is a highly **modifiable risk factor** for CHD as it can be completely stopped [1], [2]. - **Cessation of smoking** significantly reduces the risk of heart attack and stroke over time [1]. *Hypertension* - Hypertension is a **modifiable risk factor** for CHD because blood pressure can be lowered through lifestyle interventions, such as diet and exercise, and pharmacotherapy [2]. - **Uncontrolled high blood pressure** places increased stress on the heart and blood vessels, accelerating the development of atherosclerosis [1].

Q: Type 3 respiratory failure occurs due to ?

Post-operative atelectasis. ***Post-operative atelectasis*** - **Type 3 respiratory failure**, also known as **perioperative respiratory failure**, is characterized by hypoxemia occurring typically after surgery. - **Atelectasis**, the collapse of lung tissue, is a common cause of hypoxemia in the post-operative period due to shallow breathing, pain, and anesthesia affecting lung volumes. *Kyphoscoliosis* - This condition leads to a **restrictive lung disease** due to chest wall deformity, causing chronic respiratory failure. [1] - It more typically results in **Type 2 respiratory failure** (hypercapnic) due to impaired ventilation over time. [1] *Flail chest* - Flail chest is a severe chest wall injury causing paradoxical movement, leading to **acute respiratory failure**. - It is often associated with **Type 1 (hypoxemic)** or **Type 2 (hypercapnic)** respiratory failure due to trauma-induced lung injury and impaired mechanics. *Pulmonary fibrosis* - This is a progressive interstitial lung disease causing **restrictive ventilatory defect** and impaired gas exchange. - It leads to chronic **Type 1 respiratory failure** (hypoxemic) as the lung tissue becomes stiff and scarred.

Q: In which condition are Pseudo-Pelger-Huët cells typically seen?

Myelodysplastic syndrome. ***Mylodysplastic syndrome*** - Pseudo-Pelger-Huet cells are characteristic and often observed in myelodysplastic syndromes, indicating an ineffective hematopoiesis [1]. - These cells appear as **hyposegmented neutrophils** and are associated with dysplastic changes in the bone marrow [1]. *Hairy cell leukemia* - Typically presents with **hairy cells** in peripheral blood and often involves splenomegaly; pseudo-Pelger-Huet cells are not usual in this condition. - Associated with **PANCYTOPENIA** and reticulin fibrosis, differing from myelodysplastic syndrome. *Hodgkin's lymphoma* - Characterized by the presence of **Reed-Sternberg cells** and typically involves lymphadenopathy. - Peripheral blood findings generally do not include pseudo-Pelger-Huet cells; the focus is on lymphatic tissue. *Multiple myeloma* - Commonly presents with **plasma cells** and related symptoms like bone pain and renal failure, not associated with pseudo-Pelger-Huet cells. - It primarily causes an increase in monoclonal proteins rather than dysplastic changes seen in myelodysplastic syndrome. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. Common Clinical Problems From Blood And Bone Marrow Disease, pp. 613-614.

Q: HLA is located on ?

Short arm of chr-6. ***Short arm of chr-6*** - The **Human Leukocyte Antigen (HLA)** complex, crucial for immune recognition, is located on the **short arm of chromosome 6**. [1] - This region, specifically 6p21.3, contains highly polymorphic genes encoding MHC (Major Histocompatibility Complex) proteins. [2] *Long arm of chr-6* - The **long arm of chromosome 6** contains many genes, but the primary HLA complex is not located here. - Genes on the long arm are involved in various cellular functions, but not central to immune recognition via HLA. *Short arm of chr-3* - Genes on **chromosome 3**, including its short arm, are not associated with the primary HLA complex. - Chromosome 3 is known for genes related to conditions such as von Hippel-Lindau disease. *Long arm of chr-3* - The **long arm of chromosome 3** is not the location for the HLA complex. - This region contains genes involved in diverse cellular processes and disease associations, but not immune recognition via HLA molecules. **References:** [1] Cross SS. Underwood's Pathology: A Clinical Approach. 6th ed. (Basic Pathology) introduces the student to key general principles of pathology, both as a medical science and as a clinical activity with a vital role in patient care. Part 2 (Disease Mechanisms) provides fundamental knowledge about the cellular and molecular processes involved in diseases, providing the rationale for their treatment. Part 3 (Systematic Pathology) deals in detail with specific diseases, with emphasis on the clinically important aspects., pp. 55-56. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Diseases of the Immune System, pp. 239-240.

Q: Most common type of calcium channels of skeletal muscles is?

L-type. ***L type*** - **L-type calcium channels**, also known as **dihydropyridine receptors (DHPRs)**, are the predominant type of calcium channel found in skeletal muscle. - In skeletal muscle, they serve as voltage sensors that **mechanically link** to ryanodine receptors (RyRs) on the sarcoplasmic reticulum to trigger calcium release without significant calcium influx from the extracellular space. *N-type* - **N-type calcium channels** are primarily found in **neurons** and play a crucial role in neurotransmitter release at synapses. - They are not the primary calcium channels involved in skeletal muscle excitation-contraction coupling. *T-type* - **T-type calcium channels** are low-voltage activated channels found in various excitable cells, including cardiac muscle and neurons, where they contribute to **pacemaker activity** and repetitive firing. - They are not the main calcium channels responsible for excitation-contraction coupling in skeletal muscle. *R-type* - **R-type calcium channels** are found in various neural cells and are involved in diverse functions, including **synaptic transmission**, but their precise physiological role is less clearly defined compared to other types. - These channels are not the primary calcium entry pathways in skeletal muscle and do not play a significant role in its contraction.

Q: Normal range of serum osmolality is (mOsm/Kg)?

280 - 300. ***280 - 300*** - The normal range for **serum osmolality** is generally considered to be 280-300 mOsm/Kg. - This range reflects the appropriate balance of solutes (like sodium, glucose, and urea) in the blood, which is crucial for **fluid homeostasis**. *250 - 270* - A serum osmolality in this range would indicate **hypoosmolality**, suggesting a relative excess of water or a deficit of solutes in the blood. - This could be seen in conditions like **syndrome of inappropriate antidiuretic hormone (SIADH)** or primary polydipsia. *300 - 320* - This range suggests **hyperosmolality**, meaning there's a relative deficit of water or an excess of solutes. - Conditions such as **dehydration**, uncontrolled diabetes mellitus, or severe hypernatremia can lead to values in this range. *210 - 230* - Such a significantly low osmolality would represent severe **hypoosmolality**, usually associated with extreme overhydration or profound solute depletion. - This deviation is critically abnormal and would indicate severe electrolyte imbalance, potentially leading to **cerebral edema**.

Question 1

Which muscle will be paralyzed when the radial nerve is injured just below the spiral groove?

Accepted Answer

Extensor Carpi Radialis Brevis

Answer

Extensor Digitorum

Answer

Supinator

Answer

Abductor Pollicis Longus

Question 2

Which nucleus is primarily involved in the Papez circuit?

Accepted Answer

Anterior nucleus of the thalamus

Answer

Pulvinar nucleus

Answer

Intralaminar nucleus

Answer

Ventral posterolateral (VPL) nucleus

Question 3

Which of the following is the major glycosaminoglycan of synovial fluid?

Accepted Answer

Hyaluronic acid

Answer

Chondroitin sulfate

Answer

Dermatan sulfate

Answer

Heparan sulfate

Question 4

Which organelle produces and destroys H2O2?

Accepted Answer

Peroxisome

Answer

Lysosome

Answer

Golgi body

Answer

Ribosome

Question 5

Which of the following is a non- modifiable risk factor for CHD -

Accepted Answer

Old age

Answer

Diabetes

Answer

Smoking

Answer

Hypertension

Question 6

Type 3 respiratory failure occurs due to ?

Accepted Answer

Post-operative atelectasis

Answer

Kyphoscoliosis

Answer

Flail chest

Answer

Pulmonary fibrosis

Question 7

In which condition are Pseudo-Pelger-Huët cells typically seen?

Accepted Answer

Myelodysplastic syndrome

Answer

Hairy cell leukemia

Answer

Multiple myeloma

Answer

Hodgkin's lymphoma

Question 8

HLA is located on ?

Accepted Answer

Short arm of chr-6

Answer

Long arm of chr-6

Answer

Short arm of chr-3

Answer

Long arm of chr-3

Question 9

Most common type of calcium channels of skeletal muscles is?

Accepted Answer

L-type

Answer

N-type

Answer

T-type

Answer

R-type

Question 10

Normal range of serum osmolality is (mOsm/Kg)?

Accepted Answer

280 - 300

Answer

250 - 270

Answer

300 - 320

Answer

210 - 230

NEET-PG 2013

Anatomy

Biochemistry

Community Medicine

Internal Medicine

Pathology

Physiology