Sensory Systems Practice Questions

Q: Horizontal acceleration with forward movement in the sagittal plane is detected by ?

Macula of Utricle. ***Macula of Utricle*** - The **utricle** is primarily responsible for detecting **horizontal linear acceleration**, such as forward/backward and side-to-side movements in the **sagittal and coronal planes**. - Its **macula** is oriented **horizontally**, making it the ideal structure for sensing horizontal acceleration with forward movement in the sagittal plane. - The utricle contains otoliths (calcium carbonate crystals) that shift with linear acceleration, stimulating hair cells that signal movement direction. *Macula of Saccule* - The **saccule** is primarily responsible for detecting **vertical linear acceleration** of the head, such as moving up and down in an elevator. - Its macula is oriented **vertically**, not horizontally, making it unsuitable for detecting horizontal forward movement. - While it may have minor secondary roles in certain head positions, it is NOT the primary detector for horizontal sagittal plane movement. *Lateral semicircular canal* - The **lateral semicircular canal** detects **rotational acceleration** primarily in the **horizontal plane**, such as turning the head from side to side (yaw rotation). - It does **not** detect linear acceleration like forward movement—only angular/rotational movements. *Posterior semicircular canal* - The **posterior semicircular canal** detects **rotational acceleration** when the head moves in the **sagittal plane**, like nodding (pitch rotation). - It works in conjunction with the anterior semicircular canal to detect head rotations, not linear acceleration.

Q: A person with blue color vision deficiency is called?

Tritanopia. ***Tritanopia*** - This is a **rare form of blue-yellow color blindness** resulting from the **complete absence of functional blue cone photopigments** (S-cones). - People with tritanopia perceive the world in shades of red and green, with blue and yellow appearing washed out or gray. - This represents the **definitive form of blue color vision deficiency**, affecting approximately 1 in 10,000 individuals. - **Key clinical features**: Confusion between blue and green, violet appears as red, inability to distinguish yellow from pink or gray. *Tritanomaly* - This condition refers to a **mild form of blue-yellow color blindness**, where the blue cone photopigments are impaired but still present. - Individuals with tritanomaly have difficulty distinguishing shades of blue and yellow, and violet may appear pinkish. - This is a **partial blue deficiency** (anomalous trichromacy), less severe than tritanopia. *Deuteranomaly* - This is the most common type of **red-green** color vision deficiency, where the green cone photopigment is anomalous. - **Not a blue deficiency** - people with deuteranomaly have difficulty distinguishing between certain shades of red and green. *Deuteranopia* - This is a more severe form of **red-green** color blindness with complete absence of functional green cone photopigments. - **Not a blue deficiency** - individuals perceive only two primary colors (blue and yellow) and have significant difficulty with red-green discrimination.

Q: Umami taste is evoked by?

Glutamic acid. ***Glutamic acid*** - Umami is known as the **fifth basic taste** alongside sweet, sour, salty, and bitter. - It is primarily elicited by **L-glutamate**, an amino acid found in many protein-rich foods and fermented products. *Glucose* - **Glucose** is a simple sugar and is responsible for the **sweet taste**. - It does not directly evoke the umami sensation. *Quinine* - **Quinine** is a compound known for its intense **bitter taste**. - It is often used as a reference substance for bitterness perception studies. *Sodium chloride* - **Sodium chloride**, commonly known as table salt, is responsible for the **salty taste**. - It plays no direct role in eliciting the umami taste sensation.

Q: Which Brodmann's areas are primarily associated with somatosensory perception?

1, 2, 3. ***1, 2, 3*** - **Brodmann areas 1, 2, and 3** comprise the **primary somatosensory cortex**, responsible for processing sensory input from the body, such as **touch, temperature, pain, and proprioception**. - These areas are located in the **postcentral gyrus** of the parietal lobe. *4, 6* - **Brodmann area 4** is the **primary motor cortex**, critical for executing voluntary movements. - **Brodmann area 6** is the **premotor and supplementary motor cortex**, involved in planning and coordinating movements. *44, 45* - **Brodmann areas 44 and 45** constitute **Broca's area**, which is primarily involved in **speech production and language processing**. - Damage to this area can result in expressive aphasia. *41, 42* - **Brodmann areas 41 and 42** are the **primary auditory cortex**, responsible for processing auditory information and sound perception. - They are located in the temporal lobe.

Q: Which sense organ is primarily associated with an efferent nerve supply?

Organ of Corti. ***Organ of Corti*** - The **organ of Corti** receives efferent innervation via the **olivocochlear bundle**, which modulates the sensitivity of outer hair cells. - This efferent input helps to sharpen frequency tuning and protect the inner ear from excessive noise. *Golgi tendon organ* - The **Golgi tendon organ** is a **proprioceptor** that senses muscle tension and is supplied by afferent (sensory) fibers, not efferent. - Its primary role is to provide feedback on muscle force to the central nervous system. *Retina* - The retina is primarily a **sensory organ** containing photoreceptors that transmit visual information through afferent pathways to the brain. - While there are some interneurons, its main nerve supply is **afferent** for visual processing. *Taste bud* - Taste buds are **chemoreceptors** that detect taste stimuli and transmit signals via afferent nerve fibers to the brain. - They are not characterized by a prominent efferent nerve supply controlling their primary sensory function.

Q: Which motor protein is primarily involved in the function of the organ of Corti in the inner ear?

Myosin. ***Myosin*** - **Myosin** is crucial for the **mechanotransduction** process in the hair cells of the organ of Corti, specifically the **outer hair cells**. - It facilitates **electromotility**, allowing outer hair cells to change length in response to sound, amplifying vibrations and enhancing hearing sensitivity. *Kinesin* - **Kinesin** is primarily involved in **anterograde axonal transport** of vesicles and organelles along **microtubules** in neurons. - While present in various cell types, its main role is not directly in the sound transduction mechanism of the organ of Corti. *Actin* - **Actin** is a fundamental component of the **cytoskeleton** and forms the core of the stereocilia in hair cells. - Although essential for the structural integrity and mechanical properties of stereocilia, **actin itself is not a motor protein**; rather, it interacts with motor proteins like myosin. *Dynein* - **Dynein** is primarily responsible for **retrograde axonal transport** along microtubules and the movement of **cilia and flagella**. - It plays a role in cellular transport, but not directly in the active sound amplification or mechanotransduction within the organ of Corti.

Q: What is the SI unit of luminous intensity?

Candela. ***Candela*** - The **candela (cd)** is the **SI base unit** used to measure **luminous intensity**. - **Luminous intensity** quantifies the power emitted by a light source in a particular direction per unit solid angle. *Lumen* - The **lumen (lm)** is the **SI derived unit** for **luminous flux**, which measures the total perceived power of light. - It describes the total amount of visible light emitted by a source in all directions, not its intensity in a specific direction. *Lux* - The **lux (lx)** is the **SI derived unit** for **illuminance**, which measures how much luminous flux is spread over a given area. - It indicates the perceived brightness of a surface, rather than the intensity of the light source itself. *Coulomb* - The **coulomb (C)** is the **SI derived unit** for **electric charge**. - It is completely unrelated to light or luminous intensity.

Q: Miracle fruit is used to change the taste from?

Sour to Sweet. ***Sour to Sweet*** - The **miracle fruit** (Synsepalum dulcificum) contains a glycoprotein called **miraculin**. - Miraculin binds to taste receptors on the tongue and modifies their perception, making **sour foods taste sweet**. *Sour to Bitter* - The primary effect of miracle fruit is to convert **sour tastes into sweet tastes**, not bitter ones. - No known natural compound consistently changes sour perception to bitter. *Bitter to Sweet* - While miraculin makes sour foods sweet, it does not typically convert **bitter tastes into sweet sensations**. - Bitter taste perception involves different receptor pathways that are not significantly altered by miraculin. *Salty to Sweet* - Miracle fruit primarily targets **sour taste receptors**. - It does not have a significant effect on altering the perception of **salty tastes to sweet**.

Q: What is the intensity in decibel of normal conversation in humans?

60dB. ***60dB*** - The sound intensity of **normal human conversation** is typically around **60 decibels (dB)**. - This level is considered **moderate** and is comfortably audible without causing discomfort or hearing damage. *30dB* - A sound intensity of **30dB** is characteristic of a **quiet whisper** or a **soft rustle of leaves**. - This level is much **quieter** than a normal conversation and would require closer proximity to be clearly heard. *90dB* - **90dB** represents a significantly **louder sound**, comparable to that of a **lawnmower** or a **heavy truck** passing by. - Prolonged exposure to sounds at this intensity can start to cause **hearing damage**. *150dB* - **150dB** is an **extremely loud** and potentially **painful** sound level, similar to a **jet engine at takeoff** or a **firecracker** exploding nearby. - Exposure to sounds this intense can cause **immediate and permanent hearing loss**.

Question 1

Horizontal acceleration with forward movement in the sagittal plane is detected by ?

Accepted Answer

Macula of Utricle

Answer

Macula of Saccule

Answer

Lateral semicircular canal

Answer

Posterior semicircular canal

Question 2

A person with blue color vision deficiency is called?

Accepted Answer

Tritanopia

Answer

Tritanomaly

Answer

Deuteranomaly

Answer

Deuteranopia

Question 3

Umami taste is evoked by?

Accepted Answer

Glutamic acid

Answer

Glucose

Answer

Quinine

Answer

Sodium chloride

Question 4

Which Brodmann's areas are primarily associated with somatosensory perception?

Accepted Answer

1, 2, 3

Answer

4, 6

Answer

44, 45

Answer

41, 42

Question 5

Which sense organ is primarily associated with an efferent nerve supply?

Accepted Answer

Organ of Corti

Answer

Golgi tendon organ

Answer

Retina

Answer

Taste bud

Question 6

Which motor protein is primarily involved in the function of the organ of Corti in the inner ear?

Accepted Answer

Myosin

Answer

Kinesin

Answer

Dynein

Answer

Actin

Question 7

Weber Fechner law is related to?

Accepted Answer

Relationship between intensity of stimulus and sensation felt

Answer

Phantom limb

Answer

Force of contraction in heart

Answer

Cortical plasticity

Question 8

What is the SI unit of luminous intensity?

Accepted Answer

Candela

Answer

Lumen

Answer

Lux

Answer

Coulomb

Question 9

Miracle fruit is used to change the taste from?

Accepted Answer

Sour to Sweet

Answer

Sour to Bitter

Answer

Bitter to Sweet

Answer

Salty to Sweet

Question 10

What is the intensity in decibel of normal conversation in humans?

Accepted Answer

60dB

Answer

30dB

Answer

90dB

Answer

150dB

Sensory Systems — MCQs

Sensory Systems — MCQs

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