1.
Which of the following statements describes a way that a primary afferent is different from an alpha motor neuron
Correct Answer
B. The trigger zone of primary afferents can be far from the cell body
Explanation
Primary afferents are sensory neurons that transmit information from the periphery to the central nervous system. Unlike alpha motor neurons, which are responsible for sending signals from the central nervous system to the muscles, primary afferents have their cell bodies located in the dorsal horn of the spinal cord. Additionally, a key difference is that the trigger zone of primary afferents can be far from the cell body. This means that the initiation of an action potential can occur at a distance from the main body of the neuron. This is in contrast to alpha motor neurons, where the trigger zone is typically located closer to the cell body.
2.
Sensory receptor cells
Correct Answer
D. Typically use graded potential to release neurotransmitters in proportion to the strength of stimulus
Explanation
Sensory receptor cells typically use graded potential to release neurotransmitters in proportion to the strength of the stimulus. Graded potentials are changes in the membrane potential that vary in amplitude depending on the intensity of the stimulus. These graded potentials can cause the release of neurotransmitters, which then transmit the information to other neurons in the central nervous system (CNS). This allows for the communication of sensory information from the periphery to the CNS in a way that is proportional to the strength of the stimulus.
3.
Which sensory modality can communicate directly with the cortex without intermediary processing by the thalamus?
Correct Answer
B. Smell
Explanation
Smell is the correct answer because the olfactory system is unique in that it bypasses the thalamus and sends sensory information directly to the cortex. This means that smell can directly communicate with the brain without the need for intermediary processing or filtering by the thalamus. Unlike other sensory modalities such as hearing, taste, touch, and vision, which rely on the thalamus to transmit information to the cortex, the olfactory system has a direct pathway to the brain.
4.
Which of the following is TRUE regarding the anatomy of sensation and perception
Correct Answer
A. Perception is a function of cortical processing
Explanation
Perception is a function of cortical processing, meaning that the brain's cortex plays a crucial role in processing sensory information and interpreting it as meaningful perceptions. This suggests that perception involves higher-level cognitive processes and is not solely dependent on the sensory organs themselves.
5.
Which of the following is an example of integration with the somatic nervous
Correct Answer
A. The vestibular system controlling ocular muscles
Explanation
The vestibular system is responsible for maintaining balance and spatial orientation. It receives information from the inner ear and helps control eye movements to ensure visual stability during head movements. This integration between the vestibular system and the somatic nervous system allows for coordinated movement of the ocular muscles, ensuring that the eyes remain focused on a target despite changes in head position or movement. Therefore, the example provided is an illustration of integration with the somatic nervous system.
6.
Which of the following is NOT an example of adaptation?
Correct Answer
B. A loud noise causing the reflex turning of the head
Explanation
Adaptation refers to the process of adjusting to a stimulus or environment over time. The examples given in the question all involve some form of adaptation except for "A loud noise causing the reflex turning of the head." This is not an example of adaptation because it is a reflex action, which is an involuntary and immediate response to a stimulus. Adaptation, on the other hand, involves a gradual adjustment or change in response to a stimulus.
7.
Cranial nerves.....
Correct Answer
C. Have efferent and/or afferent components
Explanation
Cranial nerves are responsible for transmitting signals between the brain and different parts of the body. They can carry both afferent (sensory) and efferent (motor) components, allowing for bidirectional communication. This means that cranial nerves not only receive sensory information from the body and transmit it to the brain but also carry motor signals from the brain to various muscles and glands. Therefore, cranial nerves have efferent and/or afferent components.
8.
Which of the following statements is TRUE about taste buds?
Correct Answer
A. Taste buds contain sensory cells that release neurotransmitters to gustatory afferents
Explanation
Taste buds contain sensory cells that release neurotransmitters to gustatory afferents. This means that taste buds have cells that are responsible for detecting different tastes and sending signals to the brain through neurotransmitters. These neurotransmitters then transmit the taste information to the gustatory afferents, which are the nerve fibers that carry the taste signals to the brain for processing.
9.
What is the molecular mechanism behind the ability to taste sour?
Correct Answer
A. Protons cause depolarization by entering sensory cells through sodium channels and by closing potassium channels
Explanation
Protons cause depolarization by entering sensory cells through sodium channels and by closing potassium channels. This explanation suggests that when protons enter sensory cells through sodium channels, it leads to depolarization, which is a change in the electrical potential of the cell. Additionally, the closing of potassium channels also contributes to the depolarization process. This mechanism is responsible for the ability to taste sour, as the presence of protons triggers these cellular changes in sensory cells.
10.
How are olfactory sensory cells different from gustatory sensory cells?
Correct Answer
C. Olfactory cells detect one odorant; taste cells can detect many tastants
Explanation
Olfactory sensory cells and gustatory sensory cells are different in several ways. One key difference is that olfactory cells detect only one odorant, while taste cells can detect many tastants. This means that olfactory cells are specialized to respond to a specific odorant molecule, while taste cells are able to detect and respond to a variety of different molecules that contribute to different tastes. This difference in specificity allows for the perception of a wide range of tastes through the gustatory system, while the olfactory system is more focused on detecting and distinguishing specific odors.
11.
There are more types of odorant receptors than there are taste receptors
Correct Answer
A. True
Explanation
The statement is true because odorant receptors are responsible for detecting and distinguishing various smells, and there are more than 400 different types of odorant receptors in the human body. On the other hand, taste receptors are responsible for detecting different tastes, such as sweet, sour, salty, bitter, and umami, and there are only around 25 different types of taste receptors. Therefore, there are indeed more types of odorant receptors than taste receptors.
12.
What is a glomerulus?
Correct Answer
D. All of the above
Explanation
A glomerulus is a neural unit within the olfactory bulb that receives input from sensory cells with a particular odorant receptor, is activated in response to a particular chemical feature on an odorant, and its relative activation is coded along with all of the other glomeruli to elicit the perception of distinct smells. Therefore, the correct answer is "All of the above" as all the statements mentioned are true about a glomerulus.
13.
Which of the basic tastes is involved with regulating levels of sodium in our body?
Correct Answer
A. Salty
Explanation
The basic taste involved in regulating levels of sodium in our body is salty. Salt, or sodium chloride, is an essential mineral that helps maintain fluid balance and nerve function. Our taste buds are sensitive to salty tastes, and consuming salt can trigger our body's thirst response and help regulate sodium levels.
14.
How does the unmami taste stimulate neurotransmission
Correct Answer
D. Amino acids bind to GPCRs, which stimulates depolarization
Explanation
Amino acids bind to GPCRs, which stimulates depolarization. GPCRs, or G-protein coupled receptors, are a type of cell membrane receptor that are involved in signal transduction. When amino acids bind to GPCRs, it triggers a series of intracellular events that ultimately lead to depolarization of the cell membrane. This depolarization allows for the transmission of signals between neurons, facilitating neurotransmission.
15.
Which cranial nerve is responsible for taste?
Correct Answer
C. Facial nerve (VII)
Explanation
The facial nerve (VII) is responsible for taste. It contains taste fibers that innervate the anterior two-thirds of the tongue, allowing us to perceive different tastes such as sweet, sour, salty, and bitter. The olfactory nerve (I) is responsible for the sense of smell, the optic nerve (II) is responsible for vision, and the vestibulocochlear nerve (VIII) is responsible for hearing and balance.
16.
For a left side unilateral lesion of the thoracic (chest region) spinal cord, which of the following would be the observed pathology?
Correct Answer
C. No pain in the right leg, no touch sensation in the left leg
Explanation
A left side unilateral lesion of the thoracic spinal cord would affect the nerve fibers that carry pain sensation from the right leg and touch sensation from the left leg. This means that there would be no pain sensation in the right leg and no touch sensation in the left leg.
17.
Why are we able to escape from a painful stimulus before we learn to avoid the action that caused the pain?
Correct Answer
B. C fibers are slower than A-delta fibers
Explanation
C fibers are slower than A-delta fibers. This means that the pain signals transmitted by C fibers take longer to reach the brain compared to the signals transmitted by A-delta fibers. As a result, we are able to escape from a painful stimulus before we learn to avoid the action that caused the pain. This is because the immediate reaction to pain, such as pulling our hand away from a hot stove, is a reflex response that is mediated by the faster A-delta fibers. By the time the slower C fibers transmit the pain signals to the brain and we become aware of the pain, we have already taken action to remove ourselves from the source of the pain.
18.
Which is the proper sequence of events in phototransduction within a rod or cone
Correct Answer
C. Light activities opsin, closes sodium channels, hyperpolarization
Explanation
Phototransduction is the process by which light is converted into electrical signals in the retina. In rods and cones, light activates opsin, a protein that triggers a series of events. One of these events is the closing of sodium channels, which leads to hyperpolarization of the cell. Hyperpolarization means that the cell's membrane potential becomes more negative, making it less likely to generate an action potential. This is the correct sequence of events in phototransduction within a rod or cone.
19.
Which retinal pathway destination is responsible for reflex control of pupil size
Correct Answer
B. Pretectum/midbrain
Explanation
The pretectum/midbrain is responsible for reflex control of pupil size. This region of the brain receives information about the amount of light entering the eye from the retina and sends signals to the muscles of the iris to adjust the size of the pupil accordingly. This reflexive response helps regulate the amount of light that reaches the retina, ensuring optimal visual acuity in different lighting conditions. The hypothalamus is involved in regulating many physiological processes, but not specifically pupil size. The occipital lobe is primarily responsible for visual processing, while the superior colliculus is involved in visual attention and eye movements, but not pupil size control.
20.
Which neurotransmitter is primarily associated with the reward pathway in the brain?
Correct Answer
C. Dopamine
Explanation
Dopamine is the neurotransmitter most closely linked to the brain's reward pathway. It plays a crucial role in the regulation of pleasure, motivation, and reward-driven behavior. When a person experiences something rewarding, dopamine is released in areas like the nucleus accumbens, reinforcing the behavior. While serotonin is associated with mood regulation, acetylcholine with muscle activation, and GABA with inhibitory functions, dopamine specifically drives the reward system, making it central to motivation and reinforcement.
21.
If I keep my focus on a spot in front of me and turn my head to the left, the ________ rectus muscle in my right eye will contract
Correct Answer
A. Lateral
Explanation
When we turn our head to the left, the right eye needs to move towards the right to maintain a clear and focused vision. The muscle responsible for this movement is the lateral rectus muscle, which is located on the outer side of the eye. Therefore, when we turn our head to the left, the lateral rectus muscle in the right eye contracts to move the eye in the appropriate direction.
22.
Eye movement and adjustment of vision occurs because my head movement has been sensed by
Correct Answer
A. The semicircular canals
Explanation
The semicircular canals are responsible for sensing head movement and are part of the vestibular system in the inner ear. These canals contain fluid and hair cells that detect changes in the movement of the fluid when the head moves. This information is then sent to the brain, which helps in adjusting vision and maintaining balance. Therefore, the semicircular canals play a crucial role in sensing head movement and adjusting vision.
23.
How do the sensory cells within the semicircular canals transduce the environmental stimulus?
Correct Answer
C. Mechanically gated ion channel
Explanation
The sensory cells within the semicircular canals transduce the environmental stimulus through mechanically gated ion channels. These channels open or close in response to mechanical forces, such as the movement of fluid within the semicircular canals. When the channels open, ions can flow into or out of the cell, generating an electrical signal that is then transmitted to the brain for interpretation. This mechanism allows the sensory cells to convert mechanical stimuli into electrical signals, enabling us to perceive and sense changes in our body position and movement.
24.
Which of the following regarding sound transduction is TRUE?
Correct Answer
A. High amplitude sound waves are detected toward the base of the cochlea
Explanation
High amplitude sound waves are detected toward the base of the cochlea because the cochlea is tonotopically organized, meaning that different frequencies of sound are processed in different regions of the cochlea. The base of the cochlea is responsible for detecting high frequency sounds, while the apex is responsible for detecting low frequency sounds. Since high amplitude sound waves typically carry more energy, they are more likely to stimulate the basal region of the cochlea, where the hair cells are more sensitive to high frequencies.
25.
Which of the following related population coding is FALSE?
Correct Answer
C. Taste sensory cells express one type of taste receptor
Explanation
The statement that taste sensory cells express one type of taste receptor is false. Taste sensory cells actually express multiple types of taste receptors, each responsible for detecting a different taste sensation such as sweet, sour, salty, bitter, and umami. This allows us to perceive a wide range of flavors in the foods we eat.
26.
Why are rods said to have low acuity?
Correct Answer
A. Rods have high pHotosensitivity
Explanation
Rods are said to have low acuity because they have high photosensitivity. This means that they are highly sensitive to light and can detect even small amounts of light. However, rods are not as effective in distinguishing fine details and colors as cones, which have lower photosensitivity but higher acuity. Therefore, rods are primarily responsible for vision in low light conditions and for detecting motion, but they do not provide sharp and detailed vision.
27.
What would be the visual field loss after lesion to the left optic nerve?
Correct Answer
C. Left and right visual fields of the left eye
Explanation
After a lesion to the left optic nerve, there would be a loss of visual field in both the left and right visual fields of the left eye. This is because the optic nerve carries visual information from the left eye to the brain, and a lesion in this nerve would disrupt the transmission of visual signals from both the left and right visual fields of the left eye. The right eye, on the other hand, would not be affected by this specific lesion.
28.
What would be the visual field loss after lesion to the left optic tract
Correct Answer
B. Right visual field of both eyes
Explanation
After a lesion to the left optic tract, there would be a loss of the right visual field in both eyes. This is because the left optic tract carries visual information from the right visual field of both eyes. Therefore, damage to the left optic tract would result in the loss of the corresponding visual field.
29.
Rods and cones.......
Correct Answer
C. Are different in that rods become saturated in daylight
Explanation
Rods and cones are different in that rods become saturated in daylight. This means that when there is too much light, rods are unable to respond effectively and their ability to detect light decreases. On the other hand, cones are responsible for color vision and are less sensitive to light, allowing them to function better in daylight conditions. This difference in saturation levels between rods and cones highlights their distinct roles in vision under different lighting conditions.
30.
Why does light cause photoreceptor hyperpolarization?
Correct Answer
C. Opsin GPCR activation stimulates an enzyme to degrade cGMP, leading to closure of sodium channels
Explanation
Opsin GPCR activation stimulates an enzyme to degrade cGMP, leading to closure of sodium channels. This is because cGMP is necessary for keeping the sodium channels open. When the enzyme degrades cGMP, it causes a decrease in its concentration, leading to the closure of sodium channels. This closure of sodium channels results in hyperpolarization of the photoreceptor, as the influx of positive ions is inhibited.
31.
Signals from the retina to the ________ regulate circadian rhythms
Correct Answer
A. Hypothalamus
Explanation
The hypothalamus is responsible for regulating circadian rhythms, including sleep-wake cycles. It receives signals from the retina, which contains specialized cells that detect light and darkness. These signals help to synchronize the body's internal clock with the external environment. The hypothalamus then sends signals to other parts of the brain and body to control various physiological processes, such as hormone production and body temperature, that are influenced by circadian rhythms. The other options, pretectum, superior colliculus, and thalamus, are not directly involved in regulating circadian rhythms.
32.
Damage to the left optic tract would cause loss of vision in which of the following?
Correct Answer
D. The right field of vision in both eyes
Explanation
Damage to the left optic tract would cause loss of vision in the right field of vision in both eyes. The optic tracts carry visual information from the eyes to the brain. The left optic tract specifically carries information from the right visual field of both eyes. Therefore, damage to the left optic tract would result in the loss of vision in the right field of vision in both eyes.
33.
Which of the following statements regarding phototransduction and visual processing is TRUE?
Correct Answer
A. Newly synthesized pigments are needed to replace those in opsins that have bleached after pHotoactivation
Explanation
Phototransduction is the process by which light is converted into electrical signals in the retina. In this process, the pigments in the opsins of the photoreceptor cells get bleached after being exposed to light. To maintain sensitivity to light, newly synthesized pigments are needed to replace the bleached ones. This ensures that the photoreceptor cells can continue to respond to light stimuli. Therefore, the statement "Newly synthesized pigments are needed to replace those in opsins that have bleached after photoactivation" is true in the context of phototransduction and visual processing.
34.
Which of the following regarding sound transduction is FALSE?
Correct Answer
B. Hair cells release neurotransmitter onto afferents of CN VI
35.
The purpose of the vestibulo-ocular reflex is to....
Correct Answer
C. Control our ocular muscles so that our gaze can remain fixed despite our head movements
Explanation
The purpose of the vestibulo-ocular reflex is to control our ocular muscles so that our gaze can remain fixed despite our head movements. This reflex allows us to maintain visual stability by coordinating the movement of our eyes with the movements of our head. When we move our head, the vestibular system detects the changes in position and velocity, and sends signals to the ocular muscles to counteract these movements and keep our gaze fixed on a target. This reflex is crucial for clear vision during head movements and helps us maintain visual focus and stability.
36.
Which of the following statements regarding CNVIII afferent processing is TRUE?
Correct Answer
B. Sound localization by interaural delay depends on the simultaneous excitation of neurons at a particular location in the superior olive
37.
Merkel receptors...
Correct Answer
A. Have small receptive fields and are good at detecting fine detail
Explanation
Merkel receptors have small receptive fields, meaning they are sensitive to small areas of the skin. This allows them to detect fine detail, such as texture and edges. They are not specialized in detecting stretch, vibration, or pressure, which are functions of other types of receptors.
38.
If a Meissner neuron had mechanosensitive receptors that were permeable to chloride only,
Correct Answer
C. Applying pressure would result in hyperpolarization
Explanation
If a Meissner neuron had mechanosensitive receptors that were permeable to chloride only, applying pressure would result in hyperpolarization. This is because when pressure is applied, the mechanosensitive receptors would open, allowing chloride ions to enter the neuron. The influx of chloride ions would cause the inside of the neuron to become more negative, leading to hyperpolarization.
39.
Why do we perceive chile peppers as being hot?
Correct Answer
B. Because they contain a chemical that activates Trpv channels on free nerve endings
Explanation
Chile peppers are perceived as hot because they contain a chemical that activates Trpv channels on free nerve endings. These channels are responsible for detecting and transmitting sensations of heat and pain. When the chemical in chile peppers binds to these channels, it triggers a response in the nerve endings, leading to the perception of heat. This is why chile peppers are often described as having a spicy or hot taste.
40.
Which of the following is NOT an adaptive value of having two types of nociceptors?
Correct Answer
D. A slow pain that suppresses mechanorception in the spinal cord
Explanation
Having two types of nociceptors allows for a fast pain signal to help us escape a noxious stimulus and a slow pain signal to remind us to protect the painful area and learn not to repeat the action that caused the pain. However, a slow pain that suppresses mechanoreception in the spinal cord is not an adaptive value of having two types of nociceptors. This answer suggests that the slow pain inhibits the ability to sense mechanical stimuli, which would be counterproductive for survival and protection.
41.
Which is FALSE when comparing lemniscal and spinothalamic pathways?
Correct Answer
A. Both pathways "cross over" in the medulla
Explanation
The statement that both pathways "cross over" in the medulla is true, not false. In the lemniscal pathway, the crossover occurs at the level of the medulla, while in the spinothalamic pathway, the crossover occurs at the level of the spinal cord. Therefore, this statement is incorrect when comparing the two pathways.
42.
If a person had a unilateral lesion to the right side of their lower thoracic spinal cord....
Correct Answer
F. B & d
Explanation
A unilateral lesion to the right side of the lower thoracic spinal cord would result in impairment of proprioception in the right leg (option b) because the proprioceptive pathway from the lower extremities crosses over to the opposite side of the spinal cord at the level of the lower thoracic region. Additionally, pain sensation in the right leg would be impaired (option d) because the spinothalamic pathway, which carries pain sensation, also crosses over to the opposite side of the spinal cord at the level of the lower thoracic region.
43.
Which of the following explains the "gate" of ascending pain modulation in the spinal cord?
Correct Answer
D. Activation of touch receptors stimulates firing of an inhibitory neuron that synapses onto a second order spinothalamic afferent
Explanation
The "gate" of ascending pain modulation in the spinal cord refers to the mechanism by which touch stimuli can modulate the transmission of pain signals. When touch receptors are activated, they stimulate the firing of an inhibitory neuron that synapses onto a second order spinothalamic afferent. This inhibitory neuron then suppresses the transmission of pain signals, effectively closing the "gate" and reducing the perception of pain. Therefore, the correct answer is "Activation of touch receptors stimulates firing of an inhibitory neuron that synapses onto a second order spinothalamic afferent."
44.
Why do anti-inflammatory drugs help with pain
Correct Answer
D. A & b
Explanation
Anti-inflammatory drugs help with pain because they inhibit the production of prostaglandins, which can activate nociceptors and sensitize nociceptors. Prostaglandins are chemicals in the body that contribute to the inflammatory response and can increase the sensitivity of pain receptors. By reducing the production of prostaglandins, anti-inflammatory drugs can reduce pain and inflammation.
45.
Opioid receptors inhibit neurotransmission by....
Correct Answer
D. A & b
Explanation
Opioid receptors inhibit neurotransmission by closing voltage-gated calcium channels and opening K channels. This means that when opioids bind to their receptors, it prevents the influx of calcium ions into the neuron, which reduces the release of neurotransmitters. Additionally, it opens potassium channels, allowing potassium ions to exit the neuron, further inhibiting neurotransmission. Therefore, the correct answer is a & b.
46.
The spinothalamic and dorsal column pathways both comprise three neurons, with the second order neuron crossing the midline, and the third order neuron signaling from thalamus to cortex
Correct Answer
A. True
Explanation
The statement is true because both the spinothalamic and dorsal column pathways consist of three neurons. In both pathways, the second order neuron crosses the midline, allowing for the transmission of sensory information from one side of the body to the opposite side of the brain. The third order neuron then carries the signals from the thalamus to the cortex, where they are processed and perceived. Therefore, the statement accurately describes the organization of these two sensory pathways.
47.
Where are action potentials initiated in a sensory neuron?
Correct Answer
A. CNS
Explanation
Action potentials are initiated in the cell body of a sensory neuron, which is located in the central nervous system (CNS). This is where the integration of incoming signals from the dendrites occurs, and if the combined signal reaches the threshold, an action potential is generated. The axon terminal is responsible for transmitting the action potential to other neurons or effector cells, while the peripheral region refers to the parts of the neuron located outside the CNS, such as the dendrites.
48.
In a Merkel receptor, where would we find mechanically gated ion channels?
Correct Answer
D. Dendrites
Explanation
Mechanically gated ion channels are typically found on the dendrites of Merkel receptors. These ion channels are responsible for detecting mechanical stimuli, such as pressure or touch, and converting them into electrical signals that can be transmitted to the central nervous system (CNS). The dendrites of Merkel receptors are specialized structures that extend from the cell body and are highly sensitive to mechanical stimulation. Therefore, it is on the dendrites where we would expect to find mechanically gated ion channels in Merkel receptors.
49.
In thermoreceptors, which of the following is possible?
Correct Answer
B. Sodium channels that open in response to warm found within the peripHeral
Explanation
Sodium channels that open in response to warm can be found within the peripheral. This means that when the temperature increases, these sodium channels in the peripheral thermoreceptors open, allowing sodium ions to enter the cell and generate an action potential. This information is important for the body to detect and respond to changes in temperature, allowing us to sense and regulate our body temperature accordingly.
50.
Gustatory afferents found within the peripheral are find where?
Correct Answer
A. The gustatory nucleus in the medulla
Explanation
Gustatory afferents are sensory nerve fibers that carry information about taste from the tongue to the brain. These afferents are found within the peripheral taste buds located on the tongue. Once the taste information is received by the taste buds, it is transmitted to the gustatory nucleus in the medulla, which is a region in the brainstem. Therefore, the correct answer is the gustatory nucleus in the medulla.