Quiz: Sensory Physiology — 25 questions

1. What is a sensation?

A. A response generated by a gland

B. A movement produced by a muscle

C. A feeling caused by a stimulus

D. A signal carried by a motor nerve

Answer: (C)

Explanation

A sensation is the subjective feeling produced when a stimulus is detected. A motor response involves movement rather than the conscious experience caused by sensory input.

2. Which classification correctly matches each sensory group with its sources?

A. Somatic: hunger and thirst; visceral: hearing and smell; organic: muscles and tendons; special: pain and touch

B. Somatic: viscera and visceral functions; visceral: skin and joints; organic: vision and hearing; special: hunger and thirst

C. Somatic: vision and equilibrium; visceral: muscles and joints; organic: pain and temperature; special: hunger and thirst

D. Somatic: skin, muscles, and joints; visceral: viscera and visceral functions; organic: hunger, thirst, and sex; special: hearing, smell, taste, vision, and equilibrium

Answer: (D)

Explanation

The four groups are distinguished by their sources and functions: somatic, visceral, organic, and special sensations have the pairings described in the correct choice. The most plausible alternative confuses somatic sources with visceral sources and places special senses in the wrong category.

3. Which pathway and perception pattern characterizes a somatic sensation?

A. It arises from viscera, travels through autonomic nerves, and is perceived in the spinal cord

B. It arises from special sense organs, travels through motor nerves, and is perceived in skeletal muscle

C. It arises from somatic structures, travels through somatic nerves, and is perceived in the cerebral cortex

D. It arises from glands, travels through endocrine signals, and is perceived in the hypothalamus

Answer: (C)

Explanation

Somatic sensations originate in somatic structures, are conducted by somatic nerves, and reach conscious perception in the cerebral cortex. The visceral alternative describes a different sensory source and does not define somatic sensation.

4. Which set contains the three major types of somatic sensation?

A. Hormonal, motor, and autonomic sensations

B. Auditory, olfactory, and gustatory sensations

C. Visceral, organic, and special sensations

D. Mechanoreceptive, thermoreceptive, and pain sensations

Answer: (D)

Explanation

Somatic sensation includes mechanoreceptive, thermoreceptive, and pain sensations. Visceral, organic, and special sensations are categories of sensation rather than the three major somatic types.

5. A person detects the position of a limb through receptors located in deep tissues. How should this sensation be classified?

A. A proprioceptive sensation

B. A thermoreceptive sensation

C. A visceral sensation

D. An exteroreceptive sensation

Answer: (A)

Explanation

Proprioceptive sensations arise from deep receptors and provide information about body position and movement. Exteroreceptive sensations arise from cutaneous receptors and include touch, pain, and temperature.

6. How are mechanoreceptive sensations organized by receptor location?

A. They are divided into cutaneous sensations from skin receptors and deep sensations from receptors in deeper tissues

B. They are divided into organic sensations from glands and motor sensations from skeletal muscles

C. They are divided into visceral sensations from organs and special sensations from sensory organs

D. They are divided into thermal sensations from skin and pain sensations from the cerebral cortex

Answer: (A)

Explanation

Mechanoreceptive sensations are detected by mechanoreceptors and classified as cutaneous or deep according to receptor location. The visceral and special categories concern different sensory classifications rather than mechanoreceptor location.

7. Which pairing correctly identifies the type of cutaneous mechanoreceptor?

A. Free nerve endings are expanded endings

B. Pacinian and Meissner corpuscles are free nerve endings

C. Merkel discs and Ruffini corpuscles are expanded endings

D. Hair-follicle basket endings are encapsulated endings

Answer: (C)

Explanation

Merkel discs and Ruffini corpuscles are expanded endings among the cutaneous mechanoreceptors. Pacinian and Meissner corpuscles are encapsulated endings, while free nerve endings and hair-follicle basket endings belong to other groups.

8. Which comparison correctly distinguishes the muscle spindle from the Golgi tendon organ?

A. The muscle spindle detects joint position, whereas the Golgi tendon organ detects pain in skeletal muscle

B. The muscle spindle detects tendon tension, whereas the Golgi tendon organ detects stretch in the fleshy part of muscle

C. The muscle spindle detects skin pressure, whereas the Golgi tendon organ detects temperature in muscles

D. The muscle spindle detects stretch in the fleshy part of skeletal muscle, whereas the Golgi tendon organ detects tension in tendons

Answer: (D)

Explanation

The muscle spindle is a stretch receptor within the fleshy part of skeletal muscle, while the Golgi tendon organ is a tension receptor in skeletal muscle tendons. The reversed comparison assigns each receptor’s function to the other structure.

9. What distinguishes crude touch from fine touch?

A. Crude touch is poorly localized, whereas fine touch is highly localized and identifies stimulus characteristics.

B. Crude touch detects two separate points, whereas fine touch identifies the location of one stimulus.

C. Crude touch requires previous object learning, whereas fine touch depends on repetitive mechanoreceptor activation.

D. Crude touch identifies stimulus characteristics, whereas fine touch is poorly localized and needs stronger stimulation.

Answer: (A)

Explanation

Crude touch has limited localization and requires stronger stimulation, while fine touch provides precise localization and detects stimulus number and characteristics. The second option reverses these properties, which is the central distinction being tested.

10. Which ability defines tactile discrimination?

A. Perceiving two simultaneous stimuli as separate points with the eyes closed.

B. Detecting a skin stimulus after it has reached a strong intensity.

C. Identifying the position of one touched point without using visual information.

D. Recognizing a familiar object by handling it without seeing it.

Answer: (A)

Explanation

Tactile discrimination is the ability to perceive two simultaneously applied stimuli as two distinct points without vision. Identifying the position of one stimulus describes tactile localization, not tactile discrimination.

11. Which threshold-distance pattern is correct for two-point tactile perception?

A. About 1 mm at the tongue tip, 70 mm at the fingertips, and 3 mm on the back.

B. About 70 mm at the tongue tip, 1 mm at the fingertips, and 3 mm on the back.

C. About 3 mm at the tongue tip, 70 mm at the fingertips, and 1 mm on the back.

D. About 1 mm at the tongue tip, 3 mm at the fingertips, and 70 mm on the back.

Answer: (D)

Explanation

The shortest two-point threshold is about 1 mm at the tongue tip, 3 mm at the fingertips, and 70 mm on the back, shoulders, and thighs. The other patterns assign the regional thresholds to the wrong body areas.

12. A person identifies a key placed in the hand while blindfolded by feeling its shape and texture; what sensory ability is being demonstrated?

A. Crude touch, which detects poorly localized strong stimulation.

B. Tactile localization, which identifies the position of one contact point.

C. Stereognosis, which depends on previous learning and experience.

D. Tactile discrimination, which compares two simultaneous contact points.

Answer: (C)

Explanation

Stereognosis is the ability to recognize an object without vision, and it relies on prior learning and experience. Tactile discrimination instead concerns distinguishing two simultaneous points, not recognizing an object as a whole.

13. Why does pressure sensation generally require a stronger stimulus than touch sensation?

A. It depends on free nerve endings that adapt slowly to chemical skin irritation.

B. It is produced by several mechanoreceptors in subcutaneous tissues and requires more energy.

C. It arises from joint receptors that signal position and movement during muscle contraction.

D. It is generated by repetitive stimulation of receptors specialized for high-frequency vibration.

Answer: (B)

Explanation

Pressure is a mechanoreceptive sensation produced by several mechanoreceptors in subcutaneous tissues and requires more energy than touch. Repetitive receptor stimulation describes vibration, while joint receptors are associated with kinesthesia.

14. Which comparison of vibration sensitivity is accurate?

A. Meissner corpuscles respond up to about 80 cycles per second, whereas Pacinian corpuscles respond up to 500–800.

B. Pacinian corpuscles respond to slow vibration near 80 cycles per second, whereas Meissner corpuscles detect faster vibration.

C. Both receptor types respond across the same range, reaching approximately 80 cycles per second.

D. Meissner corpuscles respond up to about 500–800 cycles per second, whereas Pacinian corpuscles respond up to 80.

Answer: (A)

Explanation

Vibration results from repetitive mechanoreceptor stimulation, with Meissner corpuscles responding up to about 80 cycles per second and Pacinian corpuscles up to 500–800. The second option reverses the characteristic frequency ranges of the two receptors.

15. Which sensations are included within kinesthesia?

A. Sense of pressure and sense of skin irritation.

B. Sense of two-point separation and sense of object identity.

C. Sense of vibration and sense of temperature change.

D. Sense of body position and sense of joint movement.

Answer: (D)

Explanation

Kinesthetic sensation includes awareness of position and awareness of joint movement. Pressure, itch, tactile discrimination, and vibration are distinct sensory modalities rather than the two components of kinesthesia.

16. What response is characteristically associated with itch rather than tickling?

A. Involuntary laughter, commonly produced by light repetitive stimulation of the skin.

B. Perception of two simultaneous contacts as separate points with the eyes closed.

C. Recognition of an unseen object through prior handling and sensory experience.

D. A desire to scratch, often triggered by skin irritation or substances such as histamine.

Answer: (D)

Explanation

Itch is a skin-irritation sensation that creates a desire to scratch and can be caused by moving tactile stimulation or histamine. Involuntary laughter is associated with tickling, whereas the other choices describe stereognosis and tactile discrimination.

17. Which pathway description correctly characterizes itch transmission?

A. Pacinian corpuscles transmit it through motor fibers that directly activate voluntary scratching muscles.

B. Specialized free nerve endings transmit it through slowly conducting type C fibers, and signals may enter the ventral spinothalamic tract.

C. Meissner corpuscles transmit it through rapidly conducting fibers in pathways for discriminative fine touch.

D. Ruffini endings transmit it through joint-position pathways that ascend with kinesthetic information.

Answer: (B)

Explanation

Itch is detected by highly sensitive, rapidly adapting free nerve endings and travels through slowly conducting type C fibers, potentially via the ventral spinothalamic tract. Fine touch uses discriminative sensory pathways, while Pacinian and Ruffini receptors are associated with other mechanosensory functions.

18. What does thermoreceptive sensation allow a person to perceive?

A. Different temperatures ranging from freezing to burning

B. Variations in vibration ranging from slow to rapid

C. Changes in tissue pressure ranging from light to painful

D. Differences in texture ranging from smooth to rough

Answer: (A)

Explanation

Thermoreceptive sensation refers to perceiving temperature differences across a range from freezing to burning. Pressure, vibration, and texture are conveyed by other sensory systems rather than defining thermal sensation.

19. Which statement correctly describes the distribution of thermal receptors in the skin?

A. Insensitive areas contain functional receptors of both thermal types

B. Cold and warm spots are distributed in approximately equal numbers

C. Cold spots outnumber warm spots by roughly three to ten times

D. Warm spots outnumber cold spots by roughly three to ten times

Answer: (C)

Explanation

Cold spots are found in greater numbers than warm spots, by about three to ten times, while insensitive areas lack functional cold and warm spots. The alternatives reverse this ratio or mischaracterize insensitive areas.

20. At which temperature range do cold receptors normally reach their maximal discharge?

A. 10–15°C

B. 20–25°C

C. 42–45°C

D. 35–40°C

Answer: (B)

Explanation

Cold receptors discharge across approximately 10–35°C and reach their highest activity around 20–25°C. A peak near 37°C instead characterizes warm receptors, not cold receptors.

21. A warm receptor is stimulated by a temperature of 37°C; what response is most consistent with its normal coding pattern?

A. It stops discharging and conducts impulses through rapidly myelinated fibers

B. It reaches maximal discharge and belongs primarily to Krause end bulbs

C. It reaches maximal discharge and conducts impulses through C fibers

D. It begins discharging and transmits signals through pressure-sensitive endings

Answer: (C)

Explanation

Warm receptors have maximal discharge near 37°C and transmit impulses through C fibers. Krause end bulbs are associated with cold receptors, while pressure-sensitive endings do not define warm-receptor conduction.

22. How are sensory pathways generally organized, and where are sensations perceived relative to the stimulated body?

A. They usually contain one neuron order, with perception in the stimulated receptor

B. They usually contain two neuron orders, with perception in the same cerebral cortex

C. They usually contain three neuron orders, with perception in the opposite cerebral cortex

D. They usually contain four neuron orders, with perception in the spinal cord

Answer: (C)

Explanation

Sensory pathways generally use three orders of neurons, and the resulting sensations are perceived contralaterally in the cerebral cortex. The receptors remain on the stimulated, ipsilateral body side, but perception occurs on the opposite cortical side.

23. Which pairing correctly matches a dorsal column tract with the body region it serves?

A. Gracile tract—lower body; cuneate tract—upper body

B. Gracile tract—viscera; cuneate tract—skin

C. Gracile tract—upper body; cuneate tract—lower body

D. Gracile tract—face; cuneate tract—pelvis

Answer: (A)

Explanation

The gracile tract carries sensory information from the lower body, whereas the cuneate tract carries information from the upper body. The reversed pairing confuses the two tracts, and the other pairings assign them unsupported regions.

24. Which sensory function is carried by both the gracile and cuneate tracts?

A. Vibration sensation

B. Pain sensation

C. Temperature sensation

D. Itch sensation

Answer: (A)

Explanation

The gracile and cuneate tracts convey vibration along with tactile localization, discrimination, stereognosis, weight discrimination, and kinesthesia. Temperature, pain, and itch are associated with the spinothalamic system described separately.

25. What sensory information is carried by the lateral and ventral spinothalamic tracts together?

A. Tactile localization, stereognosis, vibration, weight, and kinesthetic sensations

B. Smell, taste, language, memory, emotion, and voluntary movement

C. Fine motor control, posture, balance, hearing, and visual orientation

D. Crude touch, pressure, pain, temperature, tickle, itch, and sexual sensations

Answer: (D)

Explanation

Together, the lateral and ventral spinothalamic tracts form the spinal lemniscus and carry crude touch, pressure, pain, temperature, tickle, itch, and sexual sensations. The second group belongs to the gracile and cuneate tracts, while the remaining groups are not their listed functions.