NEET-PG 2019 - Physiology PYQs Practice Questions

Q: Which of the following is the MOST CHARACTERISTIC metabolic feature of type 1 diabetes mellitus?

Increased lipolysis. ***Increased lipolysis*** - Due to **absolute insulin deficiency** in type 1 diabetes, the body cannot properly utilize glucose, leading to a shift toward **fat metabolism** for energy. - This results in increased breakdown of **triglycerides** into **fatty acids** and **glycerol**, which are then converted to **ketone bodies** in the liver. - **Ketoacidosis** resulting from increased lipolysis is the most **characteristic and distinguishing** metabolic feature of type 1 diabetes, differentiating it from type 2 diabetes. *Decreased glucose uptake* - Decreased glucose uptake by insulin-sensitive tissues (muscle and adipose tissue) is the **primary metabolic defect** in type 1 diabetes due to the absolute lack of insulin. - While this is fundamental to the pathophysiology, it occurs in **both type 1 and type 2 diabetes**, making it less characteristic of type 1 specifically. *Increased hepatic glucose output* - Increased hepatic glucose output (via gluconeogenesis and glycogenolysis) is a prominent feature due to loss of insulin's suppressive effects on the liver. - However, this also occurs in **type 2 diabetes** and is not as distinctive as the dramatic shift to lipolysis and ketone production seen in type 1. *Increased protein catabolism* - While protein catabolism is increased in type 1 diabetes, contributing to **muscle wasting** and providing substrates for gluconeogenesis, it is a less immediate and less specific feature. - The metabolic shift to **lipolysis and ketogenesis** is more rapid, more clinically significant, and more characteristic of the type 1 diabetic state. [Practice more Physiology PYQs on OnCourse]

Q: Vasopressin acts through which aquaporin channels in the collecting duct?

Aquaporin 2. ***Aquaporin 2*** - Vasopressin (ADH) stimulates the insertion of **Aquaporin 2 (AQP2)** channels into the apical membrane of collecting duct cells, increasing water reabsorption. - This process is crucial for the kidney's ability to concentrate urine and maintain **water balance**. *Aquaporin 1* - **Aquaporin 1 (AQP1)** is predominantly found in the proximal tubules and descending limb of the loop of Henle, where **constitutive water reabsorption** occurs, independent of vasopressin. - It plays a role in bulk water reabsorption rather than regulated fine-tuning. *Aquaporin 3* - **Aquaporin 3 (AQP3)** is located on the **basolateral membrane** of collecting duct cells, facilitating the exit of water from the cell into the interstitial fluid. - While essential for water movement, its insertion into the membrane is **not directly regulated by vasopressin** in the same way as AQP2. *Aquaporin 4* - **Aquaporin 4 (AQP4)** is also found on the **basolateral membrane** of collecting duct cells and in other tissues like the brain. - Similar to AQP3, it allows water to leave the cell but is not the primary target for vasopressin-mediated regulation of water permeability. [Practice more Physiology PYQs on OnCourse]

Q: With increase in age, which of the following statements about lung function is true?

Pulmonary compliance increases. ***Pulmonary compliance increases*** - With **increasing age**, there is a loss of **elastic recoil** in the lungs due to changes in elastin and collagen fibers, leading to an increase in **pulmonary compliance**. - This increased compliance means the lungs become less stiff and easier to inflate, but also less able to recoil and expel air effectively. - The **net effect** of aging is increased compliance, as the loss of elastic fibers is the predominant change in normal aging. *Residual volume decreases* - **Residual volume (RV)** actually **increases** with age. This is because the loss of elastic recoil makes it harder to fully exhale, causing more air to remain in the lungs after a maximal exhalation. - An increased residual volume contributes to an overall rise in **functional residual capacity** and total lung capacity in older adults. *Mucociliary clearance increases* - **Mucociliary clearance** generally **decreases** with age. This is due to a reduction in the number and function of cilia, as well as changes in mucus quality. - Impaired mucociliary clearance makes older individuals more susceptible to respiratory infections and difficulties in clearing secretions. *Fibrosis of the interstitium decreases* - The **fibrosis of the interstitium** can **increase** with age in some individuals. However, in normal aging (without pathological conditions), the predominant change is loss of elastic recoil rather than significant fibrotic changes. - When present, increased interstitial fibrosis would make the lungs stiffer, but this is not the primary age-related change in healthy individuals. [Practice more Physiology PYQs on OnCourse]

Q: Tubuloglomerular feedback control is useful for which one of the following?

GFR. ***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. [Practice more Physiology PYQs on OnCourse]

Q: What is the effect of the Bainbridge reflex?

Increased heart rate. ***Increased heart rate*** - The **Bainbridge reflex** produces an increase in heart rate (tachycardia). - This reflex is triggered by an increase in **venous return** and **atrial distension**, which stimulates stretch receptors in the atria, leading to increased heart rate. - The reflex helps prevent venous pooling and maintains efficient cardiac function. *Bradycardia* - **Bradycardia** (slow heart rate) is the opposite effect of the Bainbridge reflex. - Other reflexes like the **baroreceptor reflex** can cause bradycardia when arterial pressure increases. *Increased cardiac output* - While increased heart rate can contribute to **increased cardiac output**, this is a secondary consequence, not the primary effect of the reflex. - Cardiac output = Heart rate × Stroke volume, so the direct effect is on heart rate. *Decreased venous return* - The Bainbridge reflex does not cause decreased venous return. - Instead, the reflex is **triggered by increased** venous return and responds by increasing heart rate to accommodate the increased blood flow. [Practice more Physiology PYQs on OnCourse]

Question 1

Which of the following is the MOST CHARACTERISTIC metabolic feature of type 1 diabetes mellitus?

Accepted Answer

Increased lipolysis

Answer

Increased protein catabolism

Answer

Increased hepatic glucose output

Answer

Decreased glucose uptake

Question 2

Vasopressin acts through which aquaporin channels in the collecting duct?

Accepted Answer

Aquaporin 2

Answer

Aquaporin 1

Answer

Aquaporin 4

Answer

Aquaporin 3

Question 3

With increase in age, which of the following statements about lung function is true?

Accepted Answer

Pulmonary compliance increases

Answer

Fibrosis of the interstitium decreases

Answer

Residual volume decreases

Answer

Mucociliary clearance increases

Question 4

Tubuloglomerular feedback control is useful for which one of the following?

Accepted Answer

GFR

Answer

Plasma sodium

Answer

Plasma volume

Answer

Determining tubular secretion

Question 5

What is the effect of the Bainbridge reflex?

Accepted Answer

Increased heart rate

Answer

Bradycardia

Answer

Increased cardiac output

Answer

Decreased venous return

Question 6

Functional residual capacity (FRC) is defined as the volume of air remaining in the lungs at which specific moment in the respiratory cycle?

Accepted Answer

After normal expiration

Answer

During active expiration

Answer

At peak inspiration

Answer

During active inspiration

Question 7

In forceful expiration, which of the following neurons gets fired?

Accepted Answer

VRG

Answer

DRG

Answer

Pneumotaxic centre

Answer

Chemoreceptors

Question 8

What is the PRIMARY mechanism by which Interleukin-1 (IL-1) induces fever?

Accepted Answer

Endogenous pyrogen

Answer

Stimulates antibody production

Answer

Inhibits inflammation

Answer

Activates complement cascade

Question 9

Achondroplasia shows which type of inheritance?

Accepted Answer

Autosomal dominant inheritance

Answer

X-linked dominant (XLD)

Answer

Autosomal recessive inheritance

Answer

X-linked recessive (XLR)

Question 10

All are true about Decerebrate posture except:-

Accepted Answer

Flexion of upper extremity and extension of lower extremity

Answer

Exaggerated gamma motor neuron discharge

Answer

Extension of both upper and lower extremity

Answer

Reticulo spinal tract is also involved

NEET-PG 2019 — Physiology