INI-CET 2026 - Physiology PYQs Practice Questions

Q: Which physiological abnormality increases renin secretion?

Reduced renal perfusion pressure. ***Reduced renal perfusion pressure*** - Detected by **intrarenal baroreceptors** in the **afferent arteriole**, this drop in pressure directly stimulates the juxtaglomerular cells to release renin. - This is a critical compensatory mechanism to activate the **Renin-Angiotensin-Aldosterone System (RAAS)** to restore blood pressure and organ perfusion. *Increased extracellular fluid volume* - Expansion of volume suppresses renin release through both **atrial natriuretic peptide (ANP)** release and increased renal perfusion. - The body senses this as adequate pressure, leading to a down-regulation of the RAAS pathway to promote sodium excretion. *Elevated renal perfusion pressure* - High pressures stretch the **afferent arterioles**, which provides negative feedback to inhibit renin secretion. - This works in opposition to the release mechanism, ensuring systemic arterial pressure does not become excessively high under normal physiological conditions. *Elevated sodium load to macula densa* - Increased sodium-chloride delivery is sensed by the **macula densa** via the **NKCC2 co-transporter**, causing an influx of chloride that triggers the release of adenosine, which inhibits renin release. - This process is part of **tubuloglomerular feedback**, intended to regulate the glomerular filtration rate by decreasing renin when sodium delivery is high. [Practice more Physiology PYQs on OnCourse]

Q: Damage to the glomerular capillary wall causes which of the following to appear in urine?

Proteins. ***Proteins*** - The **glomerular capillary wall** serves as a size-selective barrier, normally preventing the filtration of large molecules like **plasma proteins (albumin)**. - Damage to the glomerular basement membrane or podocytes (as seen in **glomerulonephritis** or **nephrotic syndrome**) increases permeability, leading to the leakage of proteins into the urine, a condition known as **proteinuria**. *Uric acid* - Uric acid is typically elevated due to **metabolic disorders** like gout or high cell turnover states, rather than structural glomerular damage. - While uric acid crystals can form in acidic urine, their presence is not a diagnostic marker of **glomerular capillary wall injury**. *Glucose* - Glucose appears in the urine (**glycosuria**) when blood glucose levels exceed the **renal threshold** for reabsorption in the **proximal convoluted tubule**. - This is primarily a marker of **hyperglycemia** or tubular dysfunction, not glomerular filtration barrier integrity. *Ketones* - The presence of ketones in urine (**ketonuria**) indicates increased **fat metabolism**, often seen in **diabetic ketoacidosis** or prolonged fasting. - Ketones are small molecules that are freely filtered by the glomerulus and their presence is not related to damage of the capillary wall. [Practice more Physiology PYQs on OnCourse]

Q: Emotional tone and prosody of speech is primarily controlled by which brain region?

Cingulate gyrus. ***Cingulate gyrus*** - The **cingulate gyrus**, specifically the anterior portion, is deeply integrated into the **limbic system** and plays a crucial role in the processing of **emotional tone** and **affective prosody** during speech. - Damage to this region or the associated **medial frontal circuits** often results in **aprosodia** or difficulty in expressing or understanding the emotional content conveyed through vocal intonation and inflection. *Posterior superior temporal gyrus* - This region corresponds to **Wernicke's area**, which is primarily responsible for the **comprehension of language** and semantic processing rather than the emotional tone of speech. - Lesions here typically produce **receptive aphasia**, characterized by fluent but meaningless speech, rather than a deficit in affective prosody. *Posterior inferior parietal gyrus* - This area is typically associated with the **angular gyrus** and **supramarginal gyrus**, which are vital for **language processing**, reading, and integration of multisensory information. - It is not the primary center for modulating the emotional or prosodic inflection of speech. *Precentral gyrus* - The precentral gyrus serves as the **primary motor cortex**, responsible for the execution of voluntary motor movements, including the fine motor control of speech musculature (articulation). - While it allows for the physical production of words, it does not manage the underlying **emotional valence** or rhythm (prosody) of the communication. [Practice more Physiology PYQs on OnCourse]

Q: Reason for biphasic flow in right coronary artery?

Low pressure in right ventricle. ***Low pressure in right ventricle*** - The right coronary artery (RCA) supplies the right ventricle, which has a significantly lower wall pressure compared to the left ventricle, allowing for continuous myocardial perfusion throughout the cardiac cycle. - Because the **right ventricular (RV) systolic pressure** is low, mechanical compression of the coronary vessels is minimal during systole, resulting in a **biphasic flow pattern** with peaks in both systole and diastole. *Increased aortic pressure* - While higher aortic pressure generally increases coronary perfusion pressure across the entire heart, it does not specifically account for the unique **biphasic waveform** seen in the right coronary circulation. - The flow pattern is primarily determined by the **phasic intramyocardial pressure** variations rather than the absolute driving pressure provided by the aorta. *Increased right ventricular mass* - Hypertrophy of the right ventricle, such as in cases of **pulmonary hypertension**, would actually increase myocardial compressive forces and potentially attenuate or eliminate the systolic component of RCA flow. - Increased mass typically leads to higher localized resistance to flow, which would contradict the characteristic biphasic blood flow pattern observed in normal physiological states. *High pressure in right ventricle* - If the right ventricle were under high pressure, as seen in conditions like **pulmonary hypertension** or **pulmonary stenosis**, the RCA would experience profound systolic compression, often reducing or abolishing systolic flow. - High RV pressure would lead to a more **monophasic diastolic flow** pattern, similar to that observed in the left coronary artery, rather than the biphasic flow characteristic of low-pressure systems. [Practice more Physiology PYQs on OnCourse]

Q: Which adrenergic or muscarinic receptor subtype is coupled to the Gs protein?

Beta adrenergic receptor. ***Beta adrenergic receptor*** - The **beta-adrenergic receptors** (β1, β2, and β3) are classical G protein-coupled receptors that stimulate the enzyme **adenylyl cyclase** via the **Gs protein**. - Activation leads to an increase in intracellular **cyclic AMP (cAMP)**, resulting in physiological effects such as increased heart rate and bronchodilation. *M1 receptor* - This muscarinic receptor subtype is coupled to the **Gq protein**, which activates **phospholipase C**. - Its activation primarily leads to an increase in intracellular **calcium** and activation of **protein kinase C**. *M2 receptor* - The M2 muscarinic receptor is coupled to the **Gi protein**. - This leads to the **inhibition of adenylyl cyclase**, thereby decreasing levels of **cAMP** within the cell. *Alpha adrenergic receptor* - Alpha-1 receptors are coupled to the **Gq protein**, while alpha-2 receptors are coupled to the **Gi protein**. - Neither of these major alpha-receptor subtypes is linked to the **Gs protein** signaling pathway. [Practice more Physiology PYQs on OnCourse]

Question 1

Which physiological abnormality increases renin secretion?

Accepted Answer

Reduced renal perfusion pressure

Answer

Increased extracellular fluid volume

Answer

Elevated renal perfusion pressure

Answer

Elevated sodium load to macula densa

Question 2

Damage to the glomerular capillary wall causes which of the following to appear in urine?

Accepted Answer

Proteins

Answer

Uric acid

Answer

Glucose

Answer

Ketones

Question 3

Emotional tone and prosody of speech is primarily controlled by which brain region?

Accepted Answer

Cingulate gyrus

Answer

Posterior superior temporal gyrus

Answer

Posterior inferior parietal gyrus

Answer

Precentral gyrus

Question 4

Reason for biphasic flow in right coronary artery?

Accepted Answer

Low pressure in right ventricle

Answer

Increased aortic pressure

Answer

Increased right ventricular mass

Answer

High pressure in right ventricle

Question 5

Which adrenergic or muscarinic receptor subtype is coupled to the Gs protein?

Accepted Answer

Beta adrenergic receptor

Answer

Alpha adrenergic receptor

Answer

M1 receptor

Answer

M2 receptor

Question 6

In a graph of glomerular filterability vs. effective molecular radius, if X and Y are two molecules,
which statement is correct?

1. Y has more filterability than X
2. Y has more filterability than Z
3. X has less filterability than Y
4. X represents positively charged molecules

Accepted Answer

3 and 4

Answer

1 and 2

Answer

2 and 3

Answer

1 and 4

Question 7

Which sensory receptor generates a hyperpolarizing receptor potential upon stimulation?

Accepted Answer

Visual receptor (rods/cones)

Answer

Gustatory receptor

Answer

Olfactory receptor

Answer

Auditory receptor

Question 8

Which cerebral lobe primarily governs hand-eye coordination?

Accepted Answer

Parietal

Answer

Frontal

Answer

Occipital

Answer

Temporal

Question 9

Which structure in the nephron functions as the counter-current multiplier to help concentrate
urine?

Accepted Answer

Thick ascending loop of Henle

Answer

Thin ascending loop of Henle

Answer

Collecting duct

Answer

Vasa recta

Question 10

Following a bolus administration of insulin, which of the following occurs?

Accepted Answer

Glucose uptake into muscle via GLUT 4

Answer

Glucose uptake into the liver via GLUT 4

Answer

Glucose uptake into muscle via GLUT 2

Answer

Glucose uptake into the liver via GLUT 2

INI-CET 2026 — Physiology