The inability to recognize people by their faces is a troublesome problem. It can be

Watch this video (http://openstaxcollege.org/l/ DanielleReed) to learn about Dr. Danielle Reed of the Monell Chemical Senses Center in Philadelphia, PA, who became interested in science at an early age because of her sensory experiences. She recognized that her sense of taste was unique compared with other people she knew. Now, she studies the genetic differences between people and their sensitivities to taste stimuli. In the video, there is a brief image of a person sticking out their tongue, which has been covered with a colored dye. This is how Dr. Reed is able to visualize and count papillae on the surface of the tongue. People fall into two large groups known as tasters and non-tasters on the basis of the density of papillae on their tongue, which also indicates the number of taste buds. Non-tasters can taste food, but they are not as sensitive to certain tastes, such as bitterness. Dr. Reed discovered that she is a non-taster, which explains why she perceived bitterness differently than other people she knew. Are you very sensitive to tastes? Can you see any similarities among the members of your family?

Figure 14.9 The basilar membrane is the thin membrane that extends from the central core of the cochlea to the edge. What is anchored to this membrane so that they can be activated by movement of the fluids within the cochlea?

Watch this video (http://openstaxcollege.org/l/ear1) to learn more about how the structures of the ear convert sound waves into a neural signal by moving the hairs, or stereocilia, of the cochlear duct. Specific locations along the length of the duct encode specific frequencies, or pitches. The brain interprets the meaning of the sounds we hear as music, speech, noise, etc. Which ear structures are responsible for the amplification and transfer of sound from the external ear to the inner ear?

Watch this animation (http://openstaxcollege.org/l/ ear2) to learn more about the inner ear and to see the cochlea unroll, with the base at the back of the image and the apex at the front. Specific wavelengths of sound cause specific regions of the basilar membrane to vibrate, much like the keys of a piano produce sound at different frequencies. Based on the animation, where do frequenciesfrom high to low pitchescause activity in the hair cells within the cochlear duct?

Watch this video (http://openstaxcollege.org/l/ occipital) to learn more about a transverse section through the brain that depicts the visual pathway from the eye to the occipital cortex. The first half of the pathway is the projection from the RGCs through the optic nerve to the lateral geniculate nucleus in the thalamus on either side. This first fiber in the pathway synapses on a thalamic cell that then projects to the visual cortex in the occipital lobe where seeing, or visual perception, takes place. This video gives an abbreviated overview of the visual system by concentrating on the pathway from the eyes to the occipital lobe. The video makes the statement (at 0:45) that specialized cells in the retina called ganglion cells convert the light rays into electrical signals. What aspect of retinal processing is simplified by that statement? Explain your answer.

Watch this video (http://openstaxcollege.org/l/l_3-D1) to learn more about how the brain perceives 3-D motion. Similar to how retinal disparity offers 3-D moviegoers a way to extract 3-D information from the two-dimensional visual field projected onto the retina, the brain can extract information about movement in space by comparing what the two eyes see. If movement of a visual stimulus is leftward in one eye and rightward in the opposite eye, the brain interprets this as movement toward (or away) from the face along the midline. If both eyes see an object moving in the same direction, but at different rates, what would that mean for spatial movement?

The inability to recognize people by their faces is a troublesome problem. It can be caused by trauma, or it may be inborn. Watch this video (http://openstaxcollege.org/ l/faces) to learn more about a person who lost the ability to recognize faces as the result of an injury. She cannot recognize the faces of close family members or herself. What other information can a person suffering from prosopagnosia use to figure out whom they are seeing?

Watch this video (http://openstaxcollege.org/l/ motorpathway) to learn more about the descending motor pathway for the somatic nervous system. The autonomic connections are mentioned, which are covered in another chapter. From this brief video, only some of the descending motor pathway of the somatic nervous system is described. Which division of the pathway is described and which division is left out?

Visit this site (http://openstaxcollege.org/l/ NYTmotor) to read about an elderly woman who starts to lose the ability to control fine movements, such as speech and the movement of limbs. Many of the usual causes were ruled out. It was not a stroke, Parkinsons disease, diabetes, or thyroid dysfunction. The next most obvious cause was medication, so her pharmacist had to be consulted. The side effect of a drug meant to help her sleep had resulted in changes in motor control. What regions of the nervous system are likely to be the focus of haloperidol side effects?

Watch this video (http://openstaxcollege.org/l/ reflexarc) to learn more about the reflex arc of the corneal reflex. When the right cornea senses a tactile stimulus, what happens to the left eye? Explain your answer.

Watch this video (http://openstaxcollege.org/l/ newreflex) to learn more about newborn reflexes. Newborns have a set of reflexes that are expected to have been crucial to survival before the modern age. These reflexes disappear as the baby grows, as some of them may be unnecessary as they age. The video demonstrates a reflex called the Babinski reflex, in which the foot flexes dorsally and the toes splay out when the sole of the foot is lightly scratched. This is normal for newborns, but it is a sign of reduced myelination of the spinal tract in adults. Why would this reflex be a problem for an adult?

What type of receptor cell is responsible for transducing pain stimuli? a. mechanoreceptor b. nociceptor c. osmoreceptor d. photoreceptor

Which of these cranial nerves is part of the gustatory system? a. olfactory b. trochlear c. trigeminal d. facial

Which submodality of taste is sensitive to the pH of saliva? a. umami b. sour c. bitter d. sweet

Axons from which neuron in the retina make up the optic nerve? a. amacrine cells b. photoreceptors c. bipolar cells d. retinal ganglion cells

What type of receptor cell is involved in the sensations of sound and balance? a. photoreceptor b. chemoreceptor c. mechanoreceptor d. nociceptor

Which of these sensory modalities does not pass through the ventral posterior thalamus? a. gustatory b. proprioception c. audition d. nociception

Which nucleus in the medulla is connected to the inferior colliculus? a. solitary nucleus b. vestibular nucleus c. chief sensory nucleus d. cochlear nucleus

Visual stimuli in the upper-left visual field will be processed in what region of the primary visual cortex? a. inferior right b. inferior left c. superior right d. superior left

Which location on the body has the largest region of somatosensory cortex representing it, according to the sensory homunculus? a. lips b. thigh c. elbow d. neck

Which of the following is a direct target of the vestibular ganglion? a. superior colliculus b. cerebellum c. thalamus d. optic chiasm

Which region of the frontal lobe is responsible for initiating movement by directly connecting to cranial and spinal motor neurons? a. prefrontal cortex b. supplemental motor area c. premotor cortex d. primary motor cortex

Which extrapyramidal tract incorporates equilibrium sensations with motor commands to aid in posture and movement? a. tectospinal tract b. vestibulospinal tract c. reticulospinal tract d. corticospinal tract

Which region of gray matter in the spinal cord contains motor neurons that innervate skeletal muscles? a. ventral horn b. dorsal horn c. lateral horn d. lateral column

What type of reflex can protect the foot when a painful stimulus is sensed? a. stretch reflex b. gag reflex c. withdrawal reflex d. corneal reflex

What is the name for the topographical representation of the sensory input to the somatosensory cortex? a. homunculus b. homo sapiens c. postcentral gyrus d. primary cortex

The sweetener known as stevia can replace glucose in food. What does the molecular similarity of stevia to glucose mean for the gustatory sense?

Why does the blind spot from the optic disc in either eye not result in a blind spot in the visual field?

Following a motorcycle accident, the victim loses the ability to move the right leg but has normal control over the left one, suggesting a hemisection somewhere in the thoracic region of the spinal cord. What sensory deficits would be expected in terms of touch versus pain? Explain your answer.

A pituitary tumor can cause perceptual losses in the lateral visual field. The pituitary gland is located directly inferior to the hypothalamus. Why would this happen?

The prefrontal lobotomy is a drasticand largely outof-practiceprocedure used to disconnect that portion of the cerebral cortex from the rest of the frontal lobe and the diencephalon as a psychiatric therapy. Why would this have been thought necessary for someone with a potentially uncontrollable behavior?

If a reflex is a limited circuit within the somatic system, why do physical and neurological exams include them to test the health of an individual?