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Quiz: Hearing, Touch, Taste, Smell, and Pain

Test your understanding of Chapter 6. Choose the best answer, then click Show Answer to check.

Question 1

Which part of the cochlea vibrates most in response to a high-pitched sound of about 20,000 Hz?

  1. The apex, at the tip of the spiral
  2. The base, near the middle ear
  3. The middle of the spiral, for every sound
  4. The semicircular canals
Show Answer

The correct answer is B. The basilar membrane is stiff and narrow at the base, so it resonates with high frequencies, while the floppy, wide apex responds to low frequencies around 20 Hz. The apex (A) is a common mix-up because it is the "end" of the spiral. The semicircular canals (D) sense head rotation, not sound.

Concept Tested: Cochlea and Hair Cells Bloom's Level: Remember

Question 2

Which sense sends its signals to the cortex without first relaying through the thalamus?

  1. Hearing
  2. Taste
  3. Touch
  4. Smell
Show Answer

The correct answer is D. The olfactory bulb sends signals directly to the olfactory (piriform) cortex and has direct links to the amygdala. Taste (B) is a tempting choice because taste and smell work together, but taste signals pass through the thalamus before reaching the gustatory cortex in the insula.

Concept Tested: Olfaction Bloom's Level: Remember

Question 3

Which skin receptor sits deep in the skin, adapts rapidly, and is best at detecting vibration?

  1. Pacinian corpuscle
  2. Merkel disk
  3. Meissner corpuscle
  4. Ruffini ending
Show Answer

The correct answer is A. Pacinian corpuscles are deep, rapidly adapting mechanoreceptors that respond to vibration, like a phone buzzing in your pocket. Meissner corpuscles (C) also adapt rapidly, but they sit near the surface and detect light touch and slipping. Merkel disks and Ruffini endings adapt slowly.

Concept Tested: Mechanoreceptor Bloom's Level: Remember

Question 4

On the sensory homunculus, the lips and hands are drawn much larger than the back. What is the best explanation?

  1. The lips and hands have more skin surface area than the back.
  2. The lips and hands are used for movement, so they share space with the motor cortex.
  3. The lips and hands have densely packed receptors, so they need more cortex to process their input.
  4. The lips and hands are closer to the brain, so their nerves are shorter.
Show Answer

The correct answer is C. The size of each area on the somatosensory map reflects how densely the body part is supplied with receptors, not its physical size. The back actually has far more skin than the lips, so choice A is backward. Movement (B) is handled by a separate map in the motor cortex.

Concept Tested: Homunculus Bloom's Level: Understand

Question 5

Maya has a stuffed-up nose from a cold, and her favorite pizza tastes bland. Which explanation is most accurate?

  1. The cold virus has temporarily destroyed most of her taste buds.
  2. Aromas from the food cannot reach her olfactory neurons through the back of the nose, and much of flavor comes from smell.
  3. The sweet and salty zones at the tip of her tongue are swollen.
  4. Her facial nerve has stopped carrying taste signals from the front of her tongue.
Show Answer

The correct answer is B. Flavor combines taste with retronasal smell, the aromas that rise from the mouth into the nose while chewing. A blocked nose stops those aromas from reaching the olfactory sensory neurons. Choice C relies on the tongue-map myth: every part of the tongue with taste buds can detect all five tastes.

Concept Tested: Gustation Bloom's Level: Understand

Question 6

According to gate control theory, why does rubbing a bumped elbow reduce the pain?

  1. Rubbing activates large touch fibers that excite inhibitory interneurons in the dorsal horn, which reduce pain signals sent to the brain.
  2. Rubbing releases endorphins directly from the skin onto the nociceptors.
  3. Rubbing physically pushes nociceptors away from the injured tissue.
  4. Rubbing speeds up C fibers so the pain signal finishes sooner.
Show Answer

The correct answer is A. In the model proposed by Melzack and Wall in 1965, large Aβ touch fibers strongly excite inhibitory interneurons in the spinal cord's dorsal horn, which "close the gate" on projection neurons carrying pain. Endorphins (B) are real pain-reducing chemicals, but they act in the descending control system from the brain, not by release from rubbed skin.

Concept Tested: Gate Control Theory Bloom's Level: Understand

Question 7

After a fall, a patient reports numbness in a band of skin that wraps around her body at the level of her belly button. Which spinal level is most likely involved?

  1. C6
  2. T4
  3. L5
  4. T10
Show Answer

The correct answer is D. The umbilicus (belly button) is the standard key test spot for the T10 dermatome. T4 (B) is the nipple line, higher on the chest, and is a common mix-up. C6 is the thumb and L5 is the top of the foot. Remember that dermatome borders vary somewhat between people and maps.

Concept Tested: Dermatome Bloom's Level: Apply

Question 8

During brain surgery, a doctor lightly touches the patient's left thumb while recording from the cortex. Where would the strongest early response most likely appear?

  1. The left postcentral gyrus, near the top of the brain
  2. The right precentral gyrus, in front of the central sulcus
  3. The right postcentral gyrus, partway down the side of the brain between the arm and face areas
  4. The right postcentral gyrus, on the inner (medial) wall between the hemispheres
Show Answer

The correct answer is C. Touch crosses the midline, so the left thumb is mapped on the right primary somatosensory cortex in the postcentral gyrus. On the homunculus, the hand and thumb sit partway down the lateral surface, just above the face area. The medial wall (D) holds the leg and foot, and the precentral gyrus (B) is the primary motor cortex.

Concept Tested: Somatosensory Cortex Bloom's Level: Apply

Question 9

A patient has a knife wound that damaged only the right half of the spinal cord at chest level. Which finding below the injury fits the way the touch and pain pathways cross?

  1. Loss of pain and temperature on the left leg, with loss of fine touch and position sense on the right leg
  2. Loss of pain and temperature on the right leg, with loss of fine touch and position sense on the left leg
  3. Loss of all sensation on both legs
  4. Loss of all sensation on the right leg only
Show Answer

The correct answer is A. Pain fibers cross to the opposite side within the spinal cord near where they enter, so a right-sided injury interrupts pain and temperature from the left leg. Touch and position fibers climb on the same side until they cross in the medulla, so their loss is on the right. Choice B reverses the two pathways, which is the most common error. This pattern is called Brown-Séquard syndrome.

Concept Tested: Pain Pathway Bloom's Level: Analyze

Question 10

A man whose right hand was amputated reports that when his right cheek is lightly touched, he also feels touch on his missing right thumb. Which explanation best fits the evidence in this chapter?

  1. Nerves from the face have physically grown down the arm into the residual limb.
  2. The thumb was never truly represented in the cortex, so any touch can be felt there.
  3. The man is imagining the sensation because he misses his hand.
  4. The face area of the somatosensory cortex sits next to the hand area, and face input may now activate the hand's territory.
Show Answer

The correct answer is D. On the homunculus, the face area borders the hand area. After amputation, the hand area loses its input, and research by V. S. Ramachandran and others suggested that face inputs can activate it, so face touch is felt in the phantom hand. Choice C reflects the myth that phantom sensations are imaginary. Scientists still debate this explanation: a 2025 study that scanned people before and after arm amputation found that the hand map stayed largely stable. How much remapping contributes to phantom limb pain, which likely has several sources, is also debated.

Concept Tested: Phantom Limb Pain Bloom's Level: Analyze