Neurophysiology Skills Quiz

After decussation in the spinal cord, information from the leg will ascend through the anterolateral side of the spinothalamic tract. The spinothalamic tract is responsible for transmitting pain, temperature, and crude touch sensations from the body to the brain. It consists of two parts: the lateral spinothalamic tract and the anterior spinothalamic tract. The lateral spinothalamic tract carries pain and temperature sensations, while the anterior spinothalamic tract carries crude touch sensations. The anterolateral side of the spinothalamic tract specifically refers to the lateral spinothalamic tract, where information from the leg is transmitted.

the taste bud contains 3 cell types
basal cells - proliferating
supporting cells - hold everything in place
receptor cells - functional unit
the receptor cell does have connections to the dendrites of a nerve cell but the neuron is not WITHIN the taste bud

we are quite sensitive to touch thus our thresholds are low (same for temp), however we are not very sensitive to pain thus thresholds are high

the spinocerebellar tract is unique in 2 ways #1) there are only 2 cells in the pathway, #2) the information remains ipsilateral

The tonic discharge of a hair cell in the vestibular apparatus refers to the continuous firing rate of action potentials from the hair cell to the brain. This firing rate provides information about the position and movement of the head. A tonic discharge of 200 impulses/sec suggests that the hair cell is continuously sending signals to the brain at a rate of 200 action potentials per second. This firing rate is important for maintaining balance and spatial orientation.

group III nerves are small myelinated nerves... slow conduction (but faster than IV)

there are areas of overlap in temperature sensation. which is why we are very sensitive to temperature changes <~1degree
thats what dr Khankan said, i couldnt make it make sense

In terms of sound energy, the relationship between decibels and energy is logarithmic. For every 3 decibels of change, the energy of the sound doubles. This means that if the decibel level increases by 3, the sound energy will double. Similarly, if the decibel level decreases by 3, the sound energy will be halved. Therefore, the correct answer is doubles.

The middle ear increases the amplitude of a sound wave by a total of 22x, meaning it amplifies the sound wave by a factor of 22. The lever action of the ossicular bone contributes to a further amplification of 1.3x. The high amount of energy produced by the tympanic membrane and concentrated on the oval window accounts for an additional amplification of 17x.

for low frequencies [<2,000Hz] the frequency of action potentials generated by the spiral ganglia matches the frequency
frequency = cycles/sec,
spiral ganglia will match APs/sec

The vestibulo-cerebellar tract is important for the voluntary control of eye movements. The cerebellum plays a crucial role in coordinating and fine-tuning motor movements, including eye movements. The vestibulo-cerebellar tract connects the vestibular nuclei in the brainstem with the cerebellum, allowing for the integration of information from the vestibular system (responsible for balance and spatial orientation) with the cerebellum's motor control functions. This integration enables precise and coordinated eye movements, essential for visual tracking, fixation, and scanning.

The correct answer is "level of vertebrae in which muscle contraction happens." The anterior corticospinal tract remains ipsilateral (on the same side) until the level of vertebrae where muscle contraction occurs, at which point it decussates (crosses over) to the contralateral (opposite) side of the spinal cord. This decussation allows for the control of voluntary movement on the opposite side of the body.

The cells within a taste bud are replaced about every 10 days. This is because taste buds are constantly being worn down and damaged by chewing and the chemicals in food. In order to maintain their function, taste buds need to regenerate and replace old cells with new ones. This turnover process ensures that taste buds remain sensitive to different flavors and can continue to send signals to the brain about the taste of food.

information in the cuneocerebellar tract (like the spinocerebellar tract) remains unilateral, and only has two cells in the pathway, the differentiating factor is that the 1st synapse is in the brainstem.

In the auditory cortex, low frequency sounds are processed more anteriorly, and high frequency sounds are processed more posteriorly. This means that the neurons in the front part of the auditory cortex are more responsive to low frequency sounds, while the neurons in the back part of the auditory cortex are more responsive to high frequency sounds. This organization allows for efficient processing of different frequencies and helps in distinguishing various sound sources and frequencies.

In the lateral corticospinal tract, the fibers remain ipsilateral (on the same side) until just after the medulla, where they decussate (cross over to the opposite side). This crossing over allows for the contralateral (opposite side) control of motor function.

There are approximately 5,000 taste buds found in the oral/buccal cavity. Taste buds are small sensory organs located on the tongue and other parts of the mouth that allow us to perceive different tastes such as sweet, sour, salty, and bitter. These taste buds contain specialized cells that send signals to the brain, allowing us to experience the sensation of taste.

Tissue damage releases intracellular contents, specifically potassium ions (K+), which depolarizes the nociceptor. This is the correct transduction mechanism for the depolarization of nociceptors. When tissue damage occurs, intracellular contents, including potassium ions, are released into the extracellular space. The influx of potassium ions onto the nociceptor causes depolarization, leading to the generation of an action potential and the perception of pain.

The correct answer is "joint position, Ib and II". Joint receptors are sensory receptors located in the joint capsule and ligaments that sense joint position and movement. They contain group Ib and II fibers, which transmit information about joint position and movement to the central nervous system. These receptors play a crucial role in proprioception, which is the body's ability to sense the position and movement of its limbs and joints.

In acoustics, the decibel (dB) is a unit used to measure the intensity or level of sound. It is a logarithmic unit that compares the ratio of two sound intensities. The given answer, 1/10, is correct because 1 decibel is equal to 1/10 of a logarithmic unit. This means that a sound that is 1 decibel higher is equivalent to a sound that is 1/10 times more intense.

In a single cochlea, the inner hair cells are organized into a single row of 3,500 hair cells, while the outer hair cells are organized in 3-5 rows of 20,000 hair cells.

The vestibular apparatus is responsible for sensing and detecting changes in motion and orientation. The utricle, located in the inner ear, is sensitive to horizontal acceleration, which means it detects changes in speed or direction in a horizontal plane. On the other hand, the saccule, also located in the inner ear, is sensitive to vertical acceleration, which means it detects changes in speed or direction in a vertical plane.

The primary function of the basal ganglia is to store whole patterns of movement. This means that it plays a crucial role in coordinating and controlling complex motor movements. The basal ganglia receives information from various parts of the brain and helps in the planning, initiation, and execution of movements. It also helps in the regulation of muscle tone and coordination of different muscle groups. By storing patterns of movement, the basal ganglia allows for smooth and coordinated movements to occur.

the amygdala is PART of the limbic system, that is why i made limbic system incorrect

this is one of the "unique" characteristics of olfactory receptor neurons, they are neurons, they are capable of generating APs
this is different from taste receptors which have changes in membrane potential

The surface area of the tympanic membrane is 55mm2. This means that the total area of the membrane is 55 square millimeters.

pain and temp information can be sent to the dorsal funicular gray OR the substantia gleatinosa
the substantia gelatinosa is the primary pathway for pain, temp and light touch, the dorsal funicular gray is the primary pathway for mechanical and temp sensation

Sweet taste receptors initiate signal transduction by the binding of a substance to a receptor, activating its 2nd messenger system, which in turn produces cAMP. This leads to the closing of K+ channels and depolarization of the receptor. Therefore, the correct answer is sweet.

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the cerebellum uses all the information that it receives to coordinate muscular movements

The statement that the parabrachial tract relays the third-order fiber that synapses on the lateral aspect of the parietal cortex is false. The parabrachial tract actually relays the second-order fiber from the solitary nucleus to the ventroposteromedial (VPM) nucleus of the thalamus. From there, the third-order fiber projects to the primary gustatory cortex in the insula, not the parietal cortex.

Bitter taste receptors initiate signal transduction by binding a substance to a receptor, which activates its second messenger system. This activation leads to the destruction of cAMP, causing the closing of K+ channels and membrane depolarization. The bitter taste is associated with the activation of this signaling pathway.

thermoreceptors have group III & IV axons, III is small and myelinated which conducts a signal at a very slow velocity, group IV are even slower due to the lack of myelination. the stimulus is stopped and the thermoreceptors immediately cease there activity, however due to the slow conduction of signal to processing centers in the brain, it takes time for the lack of signal to reach the brain, this is also why the subject doesn't feel the pain immediately (even though the thermoreceptors begin firing right away) because it takes a while for the initial signal to reach the processing centers of the brain

Pincus domes are structures found in the skin that contain a grouping of Merkel discs. Merkel discs are specialized sensory receptors that detect light touch and pressure. These discs are located in the epidermis and are responsible for transmitting tactile information to the brain. Pincus domes serve to enhance the sensitivity and efficiency of Merkel discs, allowing for a more precise perception of touch and pressure.

Group II afferent fibers are responsible for transmitting information from specialized sensory endings in the skin. These fibers are involved in the transmission of information related to touch, pressure, and proprioception. They have a medium conduction velocity and are classified as myelinated fibers. Group II afferent fibers play a crucial role in our ability to perceive and interpret sensory stimuli from the skin.

for the jaw jerk reflex, when the jaw is presses down, muscle spindles in the muscles of the jaw will send information straight to the mesencephalic nucleus of the trigeminal. the mesencephalic nucleus will then send information to the trigeminal motor nucleus, the trigeminal motor nucleus will then excite the masseter muscle and close the jaw.

The minimum detectable difference in intensity for humans is 1db. This means that a change in intensity of at least 1 decibel is required for humans to perceive a difference in sound.

Loud noise can cause damage to the cochlea, which is responsible for hearing. The correct answer states that the damage caused by loud noise includes decreased hair cell organization and the formation of scar tissue. Hair cells in the cochlea are essential for converting sound vibrations into electrical signals that the brain can interpret as sound. When exposed to loud noise, these hair cells can become disorganized and even die, leading to a decrease in hearing ability. Additionally, the damage can result in the formation of scar tissue, which further impairs the function of the cochlea.

The pathway represented by the GOLD in this figure is the ossicular reflex pathway. This pathway is responsible for the reflexive contraction of the muscles in the middle ear, specifically the stapedius muscle, in response to loud sounds. This reflex helps to protect the delicate structures of the inner ear from damage caused by intense sound waves.

The inner hair cells in the cochlea are specialized for auditory discrimination, which means they are responsible for distinguishing different sounds and frequencies. On the other hand, the outer hair cells are specialized for auditory detection, which means they amplify and enhance the sound signals received by the inner hair cells. This division of labor allows for efficient processing of auditory information in the cochlea.

The correct sequence of the auditory pathway is as follows: stimulated hair cells -> spiral ganglia -> cochlear nucleus -> dorsal and ventral cochlear nucleus -> superior olivary formation -> inferior colliculus -> medial geniculate body -> auditory cortex (brodmann's 41,42). This sequence describes the flow of auditory information from the hair cells in the cochlea to various processing centers in the brain, ultimately leading to the perception of sound.

The round window of the cochlea is responsible for absorbing sound waves once they have cycled through the cochlea. This helps to regulate the pressure within the cochlea and prevent damage to the delicate structures inside.

The reticular formation in the brainstem is responsible for regulating overall arousal, muscle tone, eye movements, and autonomic control. However, it is not involved in somatosensory functions. Somatosensory functions are related to the perception of touch, temperature, and pain, which are primarily processed in the somatosensory cortex of the brain. The reticular formation plays a role in maintaining consciousness and regulating various physiological functions, but it does not directly process somatosensory information.

The parabrachial nuclei are involved in taste pathways to the centers for pleasure/pain, hunger/thirst/satiety but not in perceptual or reflex pathways. This means that these nuclei play a role in processing and transmitting signals related to taste and the emotional aspects of eating and drinking, but not in the perception of taste or in reflexive responses to taste stimuli.

how i remember some of them
primary Motor = 4 ---> we have 4 appendages (2 arms, 2 legs)
secondary motor = 6 --> just gotta know 2 higher than 4 = 6
Broca's area = 44, 45 --> this one is a stretch so hear me out--> Paul Broca was in his mid 50's when he died, he actually discovered Broca's area 10 years before he died = 44, 45, the numbers are fudged a little but hey... it makes sense
primary somatosensory = 3,1,2 --> you feel things before you move your hand away
secondary somatosensory = 5, 7 --> skip a few from primary then a few more
no idea for visual cortex
primary auditory = 41
secondary auditory =42 --> if you listen to loud music long enough by 42 you ain't gonna hear shit
Wernicke's = 22 --> half of the other name broca's

The substantia gelatinosa is a region in the spinal cord that plays a role in processing pain signals. Nociceptors are sensory receptors that detect harmful stimuli and transmit pain signals to the spinal cord. Mechanoreceptors, on the other hand, detect mechanical stimuli such as pressure and touch. Both nociceptors and mechanoreceptors provide input to the substantia gelatinosa, allowing it to receive information about the presence and intensity of painful stimuli. The brain also contributes to the control of pain perception by modulating the signals received from the substantia gelatinosa. Therefore, nociceptors, mechanoreceptors, and the brain are the three inputs that aid in controlling the magnitude of the perception of pain.

Group III and group IV afferent neurons are responsible for transmitting signals related to light "crude" touch and pressure (such as tickle and itch) as well as sexual stimulation. These neurons are part of the somatosensory system and play a crucial role in relaying sensory information from the skin and other tissues to the central nervous system. Group III and group IV afferent neurons are involved in the perception of various tactile sensations and are essential for the overall sensory experience.

olfactory epithelium primary afferent neuron is a small, unmyelinated neuron (group IV) making for a slow conduction of signal
think about it.... if you put you face up to a fresh baked cookie, most people have to inhale.... wait... there is the smell
same thing for farts****

glabrous (hairless skin) contains merkel discs, pacinian corpuscles, and meissner's corpuscles
according to the diagram in the manual, pincus domes are found only in hairy skin, and hair follicle endings are only found where there is hair.

hair cells do not generate action potentials

The correct answer is 3 functional units; 1.)-->[right anterior canal + left posterior canal], 2.)-->[right posterior canal + left anterior canal], 3.) -->[right and left horizontal canals]. This answer correctly describes the functional units of the semicircular canals in the vestibular apparatus. The semicircular canals are responsible for detecting rotational movements of the head in different planes. There are three pairs of semicircular canals: the anterior and posterior canals on each side, and the horizontal canals on each side. The functional units described in the answer represent the combinations of these canals that work together to detect rotational movements.

our final perception of taste is a combination of the smell (olfactory), feel of food in the mouth (tactile), memories and emotions (limbic) and of course the taste bud must be activated
without taste but activation, the whole thing come crashing down
massecation is chewing, you do not necessarily need to chew in order to taste
you don't need to see what you are tasking
motor goes along with massecation --> you can paralyze your motor neurons of the face and jaw, and still perceive taste

Merkel discs, pincus domes, and Meissner's corpuscles are types of cells that account for fine, discriminative touch. Merkel discs are found in the skin and are responsible for detecting light touch and texture. Pincus domes are specialized nerve endings found in the fingertips and are involved in the sensation of fine touch. Meissner's corpuscles are also found in the skin, particularly in areas such as the fingertips, palms, and soles of the feet, and are responsible for detecting light touch and vibration.