Sensation and Perception Questions - p. 2

Correct answer: C

The ganglion cells of the retina receive signals from other retinal neurons and their axons bundle together to form the optic nerve, which carries visual information from the brain.

Correct answer: B

The dorsal columns-medial lemniscus is the main pathway for carrying fine touch, vibration, and proprioceptive information from the body to the brain. It allows you to discriminate shapes, textures, and contours—like feeling a key in your hand and identifying it without seeing it.

Correct answer: B

The basilar membrane moves in response to fluid movement in the cochlea. These movement of the basilar membrane bends the stereocilia of hair cells in the organ of Corti, which converts mechanical energy from sound waves into neural signals that the brain interprets as sound.

Correct answer: D

The tongue is covered with many little bumps, which are sometimes mistakenly called taste buds. These small lumps of tissue are known as papillae. Taste buds are found in the walls of papillae and the grooves surrounding them, and each taste bud contains anywhere from 50 to 150 taste receptor cells.

Correct answer: B

The axons of olfactory receptor neurons in the olfactory epithelium synapse in the olfactory bulb, which is the first relay in the brain for processing smell information. From there, signals are sent to higher brain areas, including the olfactory cortex and other limbic structures, for perception and emotional responses to odors.

Correct answer: B

The primary visual cortex is found in the occipital lobe, surrounding and extending into a sulcus called the calcarine sulcus. A large band of myelinated axons runs along the edges of the calcarine sulcus, giving the primary visual cortex a striped appearance. Because of this, it is sometimes called the striate cortex.

Correct answer: B

Phototransduction works in a counterintuitive way compared to most neural signaling, where stimulation opens channels, depolarizes the cell, and increases neurotransmitter release. In photoreceptors, light lowers cGMP levels, which closes sodium channels. This hyperpolarizes the cell and reduces glutamate release. That drop in glutamate is the signal that light is present.

Correct answer: B

The vestibular system uses two organs, known as the otolith organs, to detect forward and backward movements and gravitational forces. There are two otolith organs in the vestibular labyrinth: the utricle, which detects movement in the horizontal plane, and the saccule, which detects movement in the vertical plane.

Correct answer: D

The organ of Corti is the receptor organ of the ear. It sits atop the basilar membrane and contains receptor cells known as hair cells, which convert sound vibrations into signals the nervous system can understand.

Correct answer: D

Red-green color blindness is much more common in males because the mutations that typically cause it are found on the X chromosome. If females possess such a mutation on one X chromosome, it is likely to be balanced out by a functional gene on the other X chromosome. Because males only have one X chromosome, a mutation is more likely to result in color blindness.

Correct answer: C

The fovea represents the area of the retina that provides our highest acuity vision. It has a high density of cones and very few rods.

Correct answer: C

Pain is primarily carried by two classes of peripheral axons: thinly myelinated A-delta fibers, which conduct fast, sharp, well-localized pain, and unmyelinated C fibers, which conduct slower, dull, aching, or burning pain.

Correct answer: B

Microvilli extend from taste receptor cells through an opening called the taste pore into the mouth. These microvilli come in contact with substances in the mouth that can be tasted, also known as tastants. Tastants interact with taste receptor cells through a number of different mechanisms to depolarize the cells.

Correct answer: B

The axons of olfactory receptor cells travel from the olfactory epithelium to the olfactory bulb. These axons make up the first cranial nerve, which is generally considered the shortest cranial nerve.

Correct answer: C

Normal color vision relies on three types of cones—each sensitive to different ranges of wavelengths corresponding roughly to blue, green, and red.

Correct answer: C

Pacinian corpuscles are rapidly-adapting receptors with very large receptive fields. They are thought to be most effective at transmitting information about vibrations objects cause when they are contacted or grasped by the hand. This information may be important for the use of tools.

Correct answer: B

Each of the four areas of the primary somatosensory cortex is arranged such that a particular location in that area receives information from a particular part of the body. This arrangement is referred to as somatotopic, and the full body is represented in this way in each of the four regions of the somatosensory cortex.

Correct answer: A

When light hits photoreceptors, it interacts with a molecule called photopigment, which begins a chain of events that serves to propagate the visual signal. The signal is transmitted to cells called bipolar cells, which connect photoreceptors to ganglion cells. Bipolar cells pass the signal on to ganglion cells, which leave eye in a large cluster at an area called the optic disc.

Correct answer: D

When sound waves travel through the canal of our ear, they hit the tympanic membrane (eardrum) and cause it to vibrate. This vibration prompts movement in the ossicles, a trio of tiny bones that transmit the vibration to a structure called the oval window, which sits in the wall of the cochlea.

Correct answer: B

Inside the rod cell there is a substance called rhodopsin, which is made up of a protein called opsin and a molecule called retinal, which is capable of absorbing light. When retinal absorbs light, its configuration changes, an event that initiates the process of phototransduction.

Correct answer: A

The most common type of color blindness is red-green color blindness, where individuals have difficulty distinguishing red and green hues.

Correct answer: D

Central sensitization is a rapid increase in the excitability of neurons in the dorsal horn of the spinal cord following high levels of nociceptor activity. This heightened excitability lowers the threshold for pain, increasing pain sensitivity.

Correct answer: B

When sound waves travel through the canal of our ear, they hit the tympanic membrane or eardrum and cause it to vibrate. This vibration prompts movement in the ossicles, a trio of tiny bones that transmit the vibration to a structure called the oval window, which sits in the wall of the cochlea.

Correct answer: B

Mitral cells are one of the main output neurons of the olfactory bulb. They receive synaptic input from olfactory receptor neurons (within glomeruli) and send their axons through the olfactory tract to higher brain regions, including the olfactory cortex.

Correct answer: D

The vestibular system uses two organs, known as the otolith organs, to detect forward and backward movements and gravitational forces. The two otolith organs in the vestibular labyrinth are the utricle, which detects movement in the horizontal plane, and the saccule, which detects movement in the vertical plane.

Correct answer: C

The ganglion cells leaving the eye form the optic nerve. At the optic chiasm, about 60% of the axons from the optic nerve cross over to the other side of the brain, while the rest stay on the side they originated on. After the optic chiasm, the visual fibers are no longer called the optic nerve—they’re now called the optic tract.

Correct answer: C

The primary somatosensory cortex is responsible for processing somatic sensations, or sensations from the body that include touch, proprioception or the position of the body in space, nociception or pain, and temperature.

Correct answer: B

The dorsal column–medial lemniscus pathway decussates (crosses) in the medulla. By the time it reaches the thalamus, it is already carrying information from the opposite side of the body, so a lesion here causes loss of fine touch, vibration, and proprioception on the opposite side.

Correct answer: C

Most of the visual information that leaves the retina is sent to a nucleus in the thalamus called the lateral geniculate nucleus. From there it is sent back to the primary visual cortex via large bundles of axons called the optic radiations.

Correct answer: C

The spinomesencephalic tract plays an important role in the control and inhibition of pain. Fibers in the spinomesencephalic tract follow the same path as the spinothalamic tract but they synapse in an area of the midbrain called the periaqueductal gray.