INI-CET 2023 - Physiology PYQs Practice Questions

Q: Absence or mutation of SRY gene results in ?

Gonadal dysgenesis. ***Gonadal dysgenesis*** - The **SRY gene** (Sex-determining region Y gene) is critical for initiating **male sexual differentiation**; its presence leads to testicular development. - Absence or mutation of the SRY gene prevents proper testicular development, leading to **gonadal dysgenesis**, where the gonads are either absent or rudimentary, often resulting in a **female phenotype** despite a XY genotype. *Hydrocele testis* - This condition involves an accumulation of fluid around the testis, which is typically due to a **patent tunica vaginalis** or fluid imbalance. - It does not directly result from a genetic mutation in the SRY gene affecting initial **gonadal development**. *Undescended testis* - This condition (cryptorchidism) refers to the failure of one or both testes to descend into the scrotum. - While it can have genetic components, it is not a direct consequence of an SRY gene absence or mutation, which primarily affects the **formation of the gonad itself**. *None of the options* - This option is incorrect because **gonadal dysgenesis** is a direct and well-established consequence of SRY gene absence or mutation. - The SRY gene's primary role is to trigger the development of the testis, and its dysfunction leads to profound abnormalities in **gonadal formation**. [Practice more Physiology PYQs on OnCourse]

Q: What is the order of bands in a sarcomere from the Z-disc toward the center?

Z-A-H-M. ***Z-A-H-M*** - This sequence accurately represents the arrangement of bands within a **sarcomere** when moving from the **Z-disc** towards the central **M-line**. - The **Z-disc** anchors **actin (thin) filaments**, which extend into the **A-band**, partially overlapping with myosin (thick) filaments. The **H-zone** is within the A-band, and the **M-line** bisects the H-zone. *Z-M-A-H* - This order incorrectly places the **M-line** immediately after the **Z-disc** and before the A and H bands. - The **M-line** is located at the very center of the sarcomere, a significant distance from the Z-disc. *Z-H-A-M* - This sequence incorrectly places the **H-zone** before the entire **A-band**. - The **H-zone** is a region *within* the **A-band**, specifically where only myosin (thick) filaments are present without actin (thin) overlap. *Z-H-M-A* - This order incorrectly places the **H-zone** and **M-line** before the **A-band**. - The **A-band** encompasses the entire length of the myosin (thick) filaments and includes the **H-zone** and **M-line** centrally. [Practice more Physiology PYQs on OnCourse]

Q: The bitter taste of toxic substances prevents us from their consumption, which of the following elicits the bitterness?

Alkaloids. ***Alkaloids*** - **Alkaloids** are a large group of naturally occurring chemical compounds that are mostly produced by plants, often having marked physiological actions on humans and other animals. - Many alkaloids, such as **quinine** and **strychnine**, have a characteristic **bitter taste**, which serves as a natural defense mechanism for plants against herbivores. *Aldehyde* - **Aldehydes** are organic compounds characterized by a carbonyl group to which a hydrogen atom and an R-group are attached. - While some aldehydes may have strong or pungent odors, they do not typically elicit a **bitter taste** in the same way alkaloids do; some might be sweet or fruity. *Hydrogen ions* - **Hydrogen ions (H+)** are responsible for **acidity** and are detected as a **sour taste**. - The sensation of sourness is directly related to the concentration of hydrogen ions in a substance, not bitterness. *Amino acids* - **Amino acids** are the building blocks of proteins and can elicit various tastes depending on their specific structure. - Some amino acids are **sweet** (e.g., alanine, glycine), some are **umami** (e.g., glutamate), and some are **bitter** only in certain contexts or at high concentrations, but they are not the primary group defining a broad bitter taste like alkaloids. [Practice more Physiology PYQs on OnCourse]

Q: Windkessel effect is not shown by which of the following vessel?

Radial. ***Radial*** - The **radial artery** is a muscular artery, and these vessels primarily regulate blood flow and pressure through vasoconstriction and vasodilation, rather than storing elastic energy. - While all arteries have some elasticity, the **Windkessel effect** is most prominent in large elastic arteries, which are structurally different from muscular arteries like the radial artery. *Renal* - The **renal artery** is a highly compliant, distensible artery that assists in dampening pulsatile flow and ensuring continuous, stable perfusion to the kidneys. - As a major artery off the aorta, it contributes to the **Windkessel effect** by accommodating changes in pressure during the cardiac cycle. *Aorta* - The **aorta** is the primary vessel demonstrating the **Windkessel effect** due to its high elasticity and large diameter. - During systole, it stretches and stores a significant volume of blood, releasing it during diastole to maintain a continuous flow. *Abdominal* - The **abdominal aorta** is a large elastic artery that, like the thoracic aorta, is crucial for expressing the **Windkessel effect**. - Its elastic recoil during diastole helps to sustain blood flow to the lower body and abdominal organs. [Practice more Physiology PYQs on OnCourse]

Q: Cystic fibrosis leads to defect in which of the following channels?

Cl-. ***Cl-*** - Cystic fibrosis is caused by a mutation in the **CFTR gene**, which encodes for the **Cystic Fibrosis Transmembrane Conductance Regulator protein**. - This protein functions primarily as a **chloride channel**, and its dysfunction leads to impaired chloride transport across epithelial cell membranes. *K+* - While potassium channels are crucial for many physiological processes, their primary dysfunction is **not directly linked to the pathogenesis of cystic fibrosis**. - Defects in potassium channels are associated with conditions like **long QT syndrome** or certain forms of epilepsy. *Ca2+* - **Calcium channels play a role in various cellular signaling pathways**, but their direct defect is not the underlying cause of cystic fibrosis. - Conditions like **Lambert-Eaton myasthenic syndrome** involve antibodies affecting presynaptic calcium channels. *Na+* - **Sodium channels are involved in maintaining membrane potential and fluid balance**, and while they interact with CFTR, their primary defect is not the cause of cystic fibrosis. - Dysregulation of sodium transport can occur secondary to CFTR dysfunction, leading to **dehydrated mucus**, but the initial defect is in chloride. [Practice more Physiology PYQs on OnCourse]

Question 1

Absence or mutation of SRY gene results in ?

Accepted Answer

Gonadal dysgenesis

Answer

Hydrocele testis

Answer

Undescended testis

Answer

None of the options

Question 2

What is the order of bands in a sarcomere from the Z-disc toward the center?

Accepted Answer

Z-A-H-M

Answer

Z-M-A-H

Answer

Z-H-A-M

Answer

Z-H-M-A

Question 3

The bitter taste of toxic substances prevents us from their consumption, which of the following elicits the bitterness?

Accepted Answer

Alkaloids

Answer

Aldehyde

Answer

Hydrogen ions

Answer

Amino acids

Question 4

Windkessel effect is not shown by which of the following vessel?

Accepted Answer

Radial

Answer

Renal

Answer

Aorta

Answer

Abdominal aorta

Question 5

Cystic fibrosis leads to defect in which of the following channels?

Accepted Answer

Cl-

Answer

K+

Answer

Ca2+

Answer

Na+

Question 6

Find the correct Auditory pathway sequence.

Accepted Answer

Eight nerve → cochlear nuclei → superior olivary nucleus → lateral lemniscus → inferior colliculus → medial geniculate body → auditory cortex

Answer

Superior olivary nucleus → lateral lemniscus → inferior colliculus → medial geniculate body → auditory cortex → Eight nerve → Cochlear nuclei

Answer

Cochlear nuclei → superior olivary nucleus → lateral lemniscus → inferior colliculus → medial geniculate body → auditory cortex → Eight nerve

Answer

Superior olivary nucleus → inferior colliculus → medial geniculate body → auditory cortex → Eight nerve → Cochlear nuclei → lateral lemniscus

Question 7

Arrange the following parts of sarcomere from periphery to center.

1. Z line
2. M line
3. A band
4. H zone

Accepted Answer

1,3,4,2

Answer

2,3,4,1

Answer

4,2,3,1

Answer

3,1,4,2

Question 8

Blood pressure changes in radial artery were measured. Which of the following is the reason for initial rise in BP while performing Valsalva maneuver?

Accepted Answer

Increase in aortic pressure

Answer

Increase in Left ventricular volume

Answer

Increase in Left ventricular pressure

Answer

Decrease in aortic pressure

Question 9

Assertion: RMP depends on proteins and phosphate ions.
Reason: Diffusion potential can be calculated using nernst equation.
Choose the best statement regarding the assertion and reason.

Accepted Answer

Both true, Reason is not the explanation of assertion

Answer

Assertion false, Reason true

Answer

Both true, Reason is the explanation of assertion

Answer

Assertion true, Reason false

Question 10

CO poisoning causes which type of hypoxia?

Accepted Answer

Anemic hypoxia

Answer

Hypoxic hypoxia

Answer

Stagnant hypoxia

Answer

Histotoxic hypoxia

INI-CET 2023 — Physiology