NEET-PG 2017 Practice Questions

Q: Which nerve marked as X innervates the Aortic Arch?

Aortic depressor nerve. ***Aortic depressor nerve*** - The nerve marked as X in the diagram directly innervates the **aortic baroreceptors** located in the aortic arch. - This nerve is also known as the **aortic depressor nerve**, a branch of the vagus nerve (CN X), which transmits sensory information about blood pressure from the aortic arch to the central nervous system. *Carotid sinus nerve* - The carotid sinus nerve (also known as Hering's nerve) innervates the **carotid sinus and carotid body**, which are located at the bifurcation of the common carotid artery. - This nerve transmits sensory information from the carotid baroreceptors and chemoreceptors, distinct from the aortic arch. *Inferior cervical cardiac nerve* - The inferior cervical cardiac nerve is a **sympathetic nerve** that originates from the inferior cervical ganglion and innervates the heart. - It does not primarily innervate the aortic arch baroreceptors; its function is related to cardiac rate and contractility. *Superior cervical cardiac nerve* - Similar to the inferior cervical cardiac nerve, the superior cervical cardiac nerve is a **sympathetic nerve** originating from the superior cervical ganglion. - It primarily contributes to the cardiac plexus and innervates the heart, not specifically the aortic arch baroreceptors.

Q: Which of the following is correct about the type of neuron shown below?

Pseudo-unipolar cell. ***Pseudo-unipolar cell*** - The image shows a neuron with a **single process** emerging from the cell body that then **divides into two branches** (one leading to dendrites and the other to the axon terminal), which is characteristic of a pseudo-unipolar neuron. - These neurons are typically found in **sensory ganglia**, such as the dorsal root ganglia, where they transmit sensory information. *Bipolar neuron* - A bipolar neuron has **two distinct processes** extending from the cell body: one axon and one dendrite. - Examples include neurons found in the **retina** and **olfactory epithelium**. *Unipolar cell* - A unipolar neuron has a **single process** extending from the cell body, which serves as both the dendrite and the axon. - These are typically found in **invertebrates**, though the term can sometimes be confusingly used for pseudo-unipolar neurons in some contexts. *All of the above* - This is incorrect because the neuron depicted specifically matches the morphology of a pseudo-unipolar cell, not all the listed types. - Each neuron type has distinct morphological features (number of poles/processes from the cell body).

Q: In the sarcomere diagram shown below, what do the marked areas X and Y represent?

X=H zone, Y=A band. ***X=H zone, Y=A band*** - **X** points to the central region of the A band, visible only in a relaxed sarcomere, which is called the **H zone**, containing only thick myosin filaments. - **Y** encompasses the entire length of the thick filaments, including the regions where they overlap with thin filaments, defining the **A band**. *X=A band, Y=H band* - This is incorrect because X specifically indicates the central, lighter region within the A band, which is the H zone. - Y points to the entire segment occupied by the thick filaments, which is the A band. *X=Z line, Y=M line* - The **Z line** marks the boundaries of a sarcomere, anchoring the thin (actin) filaments, and is not indicated by X. - The **M line** is the central line within the H zone that anchors the thick (myosin) filaments, and is not indicated by Y. *X=M line, Y=Z line* - As explained, X indicates the **H zone**, which is a broader region than the M line. - Y indicates the **A band**, and not the Z line; the Z line is located at the ends of the sarcomere.

Q: A head trauma patient is shown below. Diagnosis is?

Decerebrate rigidity. ***Decerebrate rigidity*** - The image shows **extension and internal rotation of the arms** with pronation, and **extension of the legs** with plantar flexion. This posture is characteristic of decerebrate rigidity. - This posturing indicates severe damage to the **brainstem**, specifically below the red nucleus, which is a more ominous sign than decorticate posturing. *Decorticate rigidity* - Decorticate rigidity would present with **flexion of the arms** at the elbows and wrists (to the core), adduction of the shoulders, and extension of the lower limbs. - This posturing is typically due to damage to the **corticospinal tracts above the red nucleus** (e.g., cerebral hemispheres, internal capsule, thalamus). *Acute dystonia* - Acute dystonia involves sustained or repetitive muscle contractions leading to **twisting and repetitive movements** or abnormal fixed postures. - It often affects specific muscle groups, such as the neck (torticollis), eyes (oculogyric crisis), or trunk, and is not typically a generalized rigidity pattern seen in head trauma as extensively as shown. *Catatonia* - Catatonia is a neuropsychiatric syndrome characterized by a variety of motor or behavioral abnormalities, including **immobility, mutism, stupor, waxy flexibility, and negativism**. - While it can involve abnormal posturing, it is a conscious state often associated with psychiatric conditions or general medical conditions, and doesn't manifest as the specific brainstem-related rigidity evident in the image.

Q: Which of the following is correct about the point marked $Z$ on the cardiac cycle?

Aortic valve opens. ***Aortic valve opens*** - At point Z, the **left ventricular pressure (LVP)** curve (solid red line) intersects and surpasses the **aortic pressure (AP)** curve (dashed line), marking the moment the **aortic valve opens** and blood begins to be ejected into the aorta. - This event signifies the transition from **isovolumetric contraction** to rapid **ventricular ejection phase** during systole. *Mitral valve opens* - The **mitral valve opens** during diastole, when the **left ventricular pressure (LVP)** falls below the **left atrial pressure (LAP)**, allowing ventricular filling. - This event would typically occur much later in the cardiac cycle, around point 5 or 6, after the aortic valve closes. *Tricuspid valve opens* - The **tricuspid valve opens** during diastole when the right ventricular pressure falls below the right atrial pressure. This event is not directly depicted for the left side of the heart in this Wigger's diagram. - It plays a role in right heart filling and is not related to the events occurring at point Z in the left heart cycle. *Mid systolic click* - A **mid-systolic click** is typically associated with **mitral valve prolapse**, occurring during mid-systole as the mitral leaflets prolapse into the left atrium. - Point Z represents the beginning of ejection, not a valvular abnormality.

Q: The pressure-volume loop of left ventricle tracing of the patient indicates:

Diastolic dysfunction. ***Diastolic dysfunction*** - The pressure-volume loop for the patient is shifted to the **left and upward** relative to the control loop, indicating higher left ventricular pressure for a given volume during diastole. - The **end-diastolic pressure-volume relationship (EDPVR)**, shown by the lower right curve, is steeper for the patient, meaning the ventricle is **stiffer or less compliant** during filling. *Systolic dysfunction* - Systolic dysfunction would be characterized by a **reduced stroke volume** (narrower loop horizontally) and a **lower ejection fraction**, often accompanied by a shift to the right due to increased end-diastolic volume. - The **end-systolic pressure-volume relationship (ESPVR)**, which represents contractility, would be shifted downwards and to the right in systolic dysfunction, indicating impaired contractility. *Decreased atrial compliance* - Decreased atrial compliance would primarily affect **atrial pressures** and the force of atrial contraction, which might indirectly impact ventricular filling, but is not directly represented by the ventricular pressure-volume loop's morphology in this manner. - The primary indicator of atrial compliance is often via atrial pressure-volume relationships or specific atrial function studies, not the ventricular loop's overall shift. *Increased atrial compliance* - Increased atrial compliance would allow the atria to accommodate more volume at lower pressures, potentially *improving* ventricular filling if the ventricle itself is compliant, but it would not explain the **elevated ventricular diastolic pressures** seen in the patient's tracing. - This condition would typically lead to lower atrial pressures, which is the opposite of what would contribute to the observed ventricular diastolic dysfunction.

Q: Which of the following dissociation curve mentioned is for myoglobin?

Green. ***Green*** - The **green curve** represents **myoglobin**, which has a much higher affinity for oxygen than hemoglobin. It binds oxygen at very low partial pressures and releases it only when oxygen levels are significantly depleted, as in active muscle tissue. - Myoglobin's dissociation curve is typically **hyperbolic** due to its single oxygen-binding site, reflecting its role in oxygen storage rather than transport. *Purple* - The **purple curve** represents normal **hemoglobin**, which exhibits a **sigmoidal** shape due to its **cooperative binding** of oxygen. This allows hemoglobin to efficiently load oxygen in the lungs and unload it in tissues. - Hemoglobin has a lower oxygen affinity than myoglobin and is designed for oxygen transport, adapting its binding based on oxygen partial pressure. *Red* - The **red curve** likely represents a **right-shifted hemoglobin dissociation curve**, indicating **decreased oxygen affinity**. This shift facilitates oxygen unloading to tissues. - Right shifts occur due to increased temperature, decreased pH (Bohr effect), increased 2,3-DPG, or increased CO₂. These physiological adaptations help deliver more oxygen to metabolically active tissues. *None* - This option is incorrect because the **green curve** clearly represents the characteristic oxygen dissociation curve for myoglobin.

Q: Which protein is responsible for the effect shown in RBC marked as $X$ ?

Band 3 protein. ***Band 3 protein*** - The image indicates that **X** facilitates the exchange of **bicarbonate (HCO₃⁻)** out of the red blood cell and **chloride (Cl⁻)** into the red blood cell, a process known as the **chloride shift** or **Hamburger phenomenon**. - This specific transporter is the **Band 3 anion exchanger 1 (AE1)**, also known as **Band 3 protein**, which is crucial for maintaining electrical neutrality during CO₂ transport. - **Band 3 protein** is the most abundant membrane protein in RBCs and accounts for approximately **25% of RBC membrane protein**. *Spectrin* - Spectrin is a **cytoskeletal protein** that forms a structural network on the inner surface of the RBC membrane. - It provides **mechanical stability and flexibility** to RBCs but does not participate in anion exchange. - Defects in spectrin cause hereditary spherocytosis and elliptocytosis. *Glycophorin* - Glycophorins are **surface glycoproteins** that carry many of the carbohydrate groups on the RBC surface. - They play roles in **membrane stability and blood group antigens** (MN blood group system). - They do not function as anion exchangers or transporters for bicarbonate/chloride. *Ankyrin* - Ankyrin is an **anchoring protein** that links the cytoskeletal protein spectrin to Band 3 protein. - It provides **structural support** and maintains membrane integrity but does not transport ions. - Ankyrin deficiency can cause hereditary spherocytosis.

Q: Identify the modality of intercellular communication shown below.

Paracrine. ***Paracrine*** - The image shows a **signaling cell** releasing **signaling molecules** (red dots) into the extracellular space, which then act on a nearby **target cell**. This local signaling is characteristic of paracrine communication. - In **paracrine signaling**, the molecules travel short distances through the interstitial fluid to influence neighboring cells, without entering the bloodstream. *Autocrine* - In **autocrine signaling**, a cell releases signaling molecules that then act on **receptors on the same cell** that produced them. The image clearly depicts communication between two different cells. - The signaling molecules are shown moving from one cell (signaling cell) to another distinct cell (target cell), rather than acting back on the originating cell. *Synaptic* - **Synaptic signaling** involves specialized structures called **synapses** where neurons transmit signals using **neurotransmitters** across a synaptic cleft to a target cell (another neuron, muscle cell, or gland cell). The image does not show a neuronal structure or a synapse. - This type of communication is highly specific to the nervous system and involves electrical impulses followed by chemical transmission, which is not represented here. *Gap junction* - **Gap junction communication** involves direct passage of signaling molecules between adjacent cells through specialized protein channels called **gap junctions**. - The image depicts signaling molecules being released into the extracellular space and binding to receptors on the target cell, rather than passing directly between the cytoplasms of two cells.

Question 1

Which nerve marked as X innervates the Aortic Arch?

Accepted Answer

Aortic depressor nerve

Answer

Carotid sinus nerve

Answer

Inferior cervical cardiac nerve

Answer

Superior cervical cardiac nerve

Question 2

Which of the following is correct about the type of neuron shown below?

Accepted Answer

Pseudo-unipolar cell

Answer

Bipolar neuron

Answer

Unipolar cell

Answer

All of the above

Question 3

In the sarcomere diagram shown below, what do the marked areas X and Y represent?

Accepted Answer

X=H zone, Y=A band

Answer

X=A band, Y=H band

Answer

X=Z line, Y=M line

Answer

X=M line, Y=Z line

Question 4

A head trauma patient is shown below. Diagnosis is?

Accepted Answer

Decerebrate rigidity

Answer

Decorticate rigidity

Answer

Acute dystonia

Answer

Catatonia

Question 5

Which of the following is correct about the point marked $Z$ on the cardiac cycle?

Accepted Answer

Aortic valve opens

Answer

Mitral valve opens

Answer

Tricuspid valve opens

Answer

Mid systolic click

Question 6

The pressure-volume loop of left ventricle tracing of the patient indicates:

Accepted Answer

Diastolic dysfunction

Answer

Systolic dysfunction

Answer

Decreased atrial compliance

Answer

Increased atrial compliance

Question 7

Which of the following dissociation curve mentioned is for myoglobin?

Accepted Answer

Green

Answer

Purple

Answer

Red

Answer

None

Question 8

Which protein is responsible for the effect shown in RBC marked as $X$ ?

Accepted Answer

Band 3 protein

Answer

Spectrin

Answer

Glycophorin

Answer

Ankyrin

Question 9

Identify the modality of intercellular communication shown below.

Accepted Answer

Paracrine

Answer

Autocrine

Answer

Synaptic

Answer

Gap junction

Question 10

The following skeletal muscle recording shows presence of: (Recent NEET Pattern 2016-17)

Accepted Answer

A = Twitch, B = Summation, C = Incomplete tetanus, D = Complete tetanus

Answer

A = Summation, B = Twitch, C = Complete tetanus, D = Incomplete tetanus

Answer

A = Twitch, B = Incomplete tetanus, C = Summation, D = Complete tetanus

Answer

A = Incomplete tetanus, B = Complete tetanus, C = Twitch, D = Summation

NEET-PG 2017

Anatomy

General Medicine

Physiology