Bio Of Brain Exam 2

1. Describe and identify the DRG cell ending types and the sensory modalities transduced by each type.

Dorsal root ganglia cells have cell bodies at both ends of the ganglia.

Dorsal root ganglia cells are located in the middle of the ganglia.

Only very end of dorsal route ganglia has cell body

The sensory modalities transduced by DRG cells are limited to taste and smell.

The correct answer highlights that the cell body is located only at the very end of the dorsal root ganglia. The incorrect answers provide false information or incorrect associations related to the structure and function of DRG cells.

Explanation

The correct answer highlights that the cell body is located only at the very end of the dorsal root ganglia. The incorrect answers provide false information or incorrect associations related to the structure and function of DRG cells.

2. What are ion channels that transduce sensory modalities? How do we know that mechanosensing channels are cation that open upon membrane displacement?

By analyzing the chemical composition of the cell membrane

By observing changes in cell shape under a microscope

By measuring the temperature changes around the cell during membrane displacement

*you can record the ion flow thru the open channels with a voltage clamp as a bar applies pressure to the cell, and categorize as SA, IA, or RA

Mechanosensing channels can be identified through specific experimental procedures involving the recording of ion flow with a voltage clamp, which allows for categorization based on response types.

Explanation

Mechanosensing channels can be identified through specific experimental procedures involving the recording of ion flow with a voltage clamp, which allows for categorization based on response types.

3. Describe and understand the difference between SA and RA currents and relate them to different physiological properties of DRGs.

SA DRG peaks quickly and adapts rapidly to the pressure stimulus.

RA DRG current remains constant as long as pressure stimulus is applied.

IA DRG only responds well to the 'first touch' pressure stimulus.

*RA DRG peaks then rapidly gets smaller as it adapts to the pressure stimulus. will only respond well to a "first touch"
*SA DRG is opposite, the current remains constant as long as a pressure stimulus is applied.
*IA DRG is in between
**** at initial stimuli, ALL THESE FIRE AT ONCE. SA's will just last longer than IA, which lasts longer than RA

In this question, the correct answer explains the behavior of RA, SA, and IA DRGs and how they respond to pressure stimuli. Incorrect answers provided do not accurately depict the differences between SA and RA currents in relation to their physiological properties.

Explanation

In this question, the correct answer explains the behavior of RA, SA, and IA DRGs and how they respond to pressure stimuli. Incorrect answers provided do not accurately depict the differences between SA and RA currents in relation to their physiological properties.

4. Describe the physiology of TRP channels and how they transduce temperature and pain info what other channels are involved in pain transduction?

TRP channels are not involved in temperature or pain transduction

TRP channels are primarily found in the brain and not in peripheral nerves

*Discovered by adding DNA coding for different channels with calcium sensitive dyes
*adding menthol (cold) or capsaicin( warm) signaled calcium flow, meaning that these TRP channels respond to temp
-permeable to Ca and Na, blocked by La
* 4 subunits, 6 membrane spanning regions
-different types of channels have optimal temp ranges
***NOCICEPTORS also transduce pain, plus burning hot and cold temperatures

TRP channels are only activated by physical pressure

The correct answer explains the involvement of TRP channels in temperature and pain transduction, along with the role of nociceptors. The incorrect answers provided do not accurately describe the physiology of TRP channels or their function in transducing temperature and pain information.

Explanation

The correct answer explains the involvement of TRP channels in temperature and pain transduction, along with the role of nociceptors. The incorrect answers provided do not accurately describe the physiology of TRP channels or their function in transducing temperature and pain information.

5. Describe a specific parallel map and an orthogonal map in the primary somatosensory cortex.

AUDITORY

SMELL

READ

TACTILE

In the primary somatosensory cortex, a specific parallel map refers to the topographical arrangement of body parts, known as the somatotopic map. An orthogonal map refers to the organization of different sensory inputs within the cortex, such as visual, auditory, and somatosensory inputs being arranged in orthogonal columns.

Explanation

In the primary somatosensory cortex, a specific parallel map refers to the topographical arrangement of body parts, known as the somatotopic map. An orthogonal map refers to the organization of different sensory inputs within the cortex, such as visual, auditory, and somatosensory inputs being arranged in orthogonal columns.

6. Describe how phantom limb sensations and pain relate to cortical maps, and how mirror box therapy indicates a 'top down' effect on sensory cortical maps.

Cortical maps have no influence on the perception of phantom limb pain.

When you lose input coming up from DRG, part of your brain won't have any S.S input
* phantom limb is caused by that area of the brain whose cells are still active
*areas that are nearby start picking up information from area that doesnt have input
-i.e for phantom limb, arm maps onto face

Phantom limb sensations are a result of actual physical limbs reappearing after amputation.

Mirror box therapy directly affects the physical reconstruction of missing limbs.

Phantom limb sensations and pain are intricately linked to cortical maps due to the reorganization of brain areas, which is why mirror box therapy, which works on the brain's perception, shows a 'top down' effect on sensory cortical maps.

Explanation

Phantom limb sensations and pain are intricately linked to cortical maps due to the reorganization of brain areas, which is why mirror box therapy, which works on the brain's perception, shows a 'top down' effect on sensory cortical maps.

7. Describe and name the descending pathways that modify pain sensation through endogenous opiates.

C. Cerebellar pathways

B. Ventral horn neurons

A. Spinothalamic tract

*gated by 2 pathways, both interneurons
1. dorsal horn neurons gray matter: gates pain by inhibiting release neurotransmitter that very first DRG releases to transduce pain
2. periaqueductal gray matter

The descending pathways that modify pain sensation through endogenous opiates involve the dorsal horn neurons in the gray matter and the periaqueductal gray matter, not the spinothalamic tract, ventral horn neurons, or cerebellar pathways.

Explanation

The descending pathways that modify pain sensation through endogenous opiates involve the dorsal horn neurons in the gray matter and the periaqueductal gray matter, not the spinothalamic tract, ventral horn neurons, or cerebellar pathways.

8. Describe the pathways and major receptors responsible for itch sensation.

B: Itch sensation is primarily mediated by the release of dopamine in the brain.

1. histamine pathway: histamine and TRPV1 GCPRs
-activated by histamine (released from inflammatory mast cells)
2. histamine independent pathway: CQ and TRPA1 GCPR's
- activated by mrgprA3
*pathway similar as pain (contralateral)
- Spinal Thalamic Tract neurons in Dorsal Spinal column fire when stimulated by gastrin releasing peptide
*** chronic morphine users experience chronic itch because morphine can activate a morphine receptor that's associated with a GRPR receptor

A: The sensation of itch is solely controlled by the nervous system.

C: Major receptors responsible for itch sensation include acetylcholine and serotonin receptors.

The correct answer provides detailed information about the pathways and major receptors responsible for itch sensation, while the incorrect answers misrepresent or provide inaccurate information about the topic.

Explanation

The correct answer provides detailed information about the pathways and major receptors responsible for itch sensation, while the incorrect answers misrepresent or provide inaccurate information about the topic.

9. Which TRP channels open to menthol and which open to capsaican?

*menthol: TRPA1(freezing cold), TRPM8 (cold)
-TRPA1 can also transduce pain
*capsaican: TRPV4 (warm temp) thru TRPV1 (very very hot)

TRPM8 to menthol, TRPV4 to capsaican

TRPV4 to menthol, TRPA1 to capsaican

TRPV1 to menthol, TRPA1 to capsaican

Menthol activates TRPA1 and TRPM8 channels, while capsaican activates TRPV4 (and TRPV1 indirectly). TRPV1 is typically associated with extreme heat rather than menthol activation.

Explanation

Menthol activates TRPA1 and TRPM8 channels, while capsaican activates TRPV4 (and TRPV1 indirectly). TRPV1 is typically associated with extreme heat rather than menthol activation.

10. What channels transduce pain?

Voltage-gated sodium channels

*P2X channels (permeable to ATP)
*TRPA1 (cold) and TRPV1 (hot)
*ASIC channel (acid pain, permeable to H+)

Potassium channels

Calcium channels

Pain sensation is transduced through various ion channels in the body. The correct answer options provided are known to play a key role in pain transduction, making them relevant choices for the question.

Explanation

Pain sensation is transduced through various ion channels in the body. The correct answer options provided are known to play a key role in pain transduction, making them relevant choices for the question.

11. Name the different tongue papillae and describe the location of taste buds, explain how they differ in content of different taste receptor cells.

1. filiform papillae: at the tip of the tongue, low content of taste receptors

1. circumvallate papillae: in back of tounge, high content of HCL and quinine receptors
2. foliate papillae: on the sides of the toungue
3. fungiform papillae: front/side of tongue, high content of sucrose, NaCl, and HCL receptors

3. reticular papillae: distributed across the tongue, with preference for umami and sour tastes.

2. saccate papillae: underneath the tongue, with a mix of sweet, bitter, and salty receptors

Taste buds are located within the papillae of the tongue, with different types of papillae containing varying concentrations of taste receptors for different tastes, such as sweet, salty, sour, bitter, and umami.

Explanation

Taste buds are located within the papillae of the tongue, with different types of papillae containing varying concentrations of taste receptors for different tastes, such as sweet, salty, sour, bitter, and umami.

12. Describe the responses of the population of chordi-tempani axons to different tastants and explain the implication of this response pattern for both the receptor types on taste cells, and for how taste info is processed (population code or labeled line).

Certain chorda tympani axons fire ate higher rates when exposed to certain tastants (theres 40 different axons)
*a lot of mixing with sweet and salty tastants

All chorda tympani axons respond equally to all tastants, indicating a labeled line theory of taste processing.

Chorda tympani axons do not respond to any tastants, implying that taste information is processed solely in the brain and not at the receptor level.

Only one chorda tympani axon is responsible for detecting all tastants, suggesting a specific labeled line for each taste.

The correct answer provided highlights that there are specific responses of chorda tympani axons to different tastants, indicating a population code for taste information processing. The incorrect answers showcase alternative scenarios that do not align with the observed response patterns and theoretical implications.

Explanation

The correct answer provided highlights that there are specific responses of chorda tympani axons to different tastants, indicating a population code for taste information processing. The incorrect answers showcase alternative scenarios that do not align with the observed response patterns and theoretical implications.

13. Identify the specific transduction channels and receptors in taste receptor cells for salty, sour, bitter, sweet and umami. Note the unique and shared mechanisms of transduction.

SALT: ENaC (sodium ion channel)
SOUR: PKD2L (hydrogen ion channel)
SWEET: T1R2 and T1R3 (shared with umami)
UMAMI: T1R1, T1R1 (shared with sweet) and TRPM5 (shared with bitter)
BITTER: T2R5 , PLCB2 (activates TRPM5 channeli) and TRPM5 calcium ion channel (shared with umami and sweet)

SALT: TRPM5; SOUR: T2R5; SWEET: ENaC; UMAMI: PKD2L

SALT: T1R1; SOUR: ENaC; SWEET: T2R5; UMAMI: PLCB2

SALT: PLCB2; SOUR: TRPM5; SWEET: PKD2L; UMAMI: T1R2

The correct answer includes the specific transduction channels and receptors for each taste sensation, highlighting their unique and shared mechanisms of transduction. The incorrect answers provided do not accurately represent the components involved in taste transduction for each taste sensation.

Explanation

The correct answer includes the specific transduction channels and receptors for each taste sensation, highlighting their unique and shared mechanisms of transduction. The incorrect answers provided do not accurately represent the components involved in taste transduction for each taste sensation.

14. Describe the nature of odorant receptor diversity and the pattern of expression of different receptors on different olfactory neurons.

Odorant receptor diversity is not important in the sense of smell.

Olfactory neurons express all types of receptors simultaneously.

Swag

Each odorant receptor can be expressed on multiple olfactory neurons.

The correct answer highlights the significance of odorant receptor diversity in olfaction and explains the specific pattern of receptor expression on olfactory neurons. The incorrect answers are refuted based on the established understanding of odorant receptor diversity and expression patterns in olfactory neurons.

Explanation

The correct answer highlights the significance of odorant receptor diversity in olfaction and explains the specific pattern of receptor expression on olfactory neurons. The incorrect answers are refuted based on the established understanding of odorant receptor diversity and expression patterns in olfactory neurons.

15. What is anosmia?

Loss of vision.

Lose sense of taste.

Hearing impairment.

*lose sense of taste

Anosmia refers to the loss of the sense of smell, not taste, vision, or hearing.

Explanation

Anosmia refers to the loss of the sense of smell, not taste, vision, or hearing.

16. Identify the locations of the first 4 synapses in the olfactory system.

3. Amygdala to parietal cortex

2. Hippocampus to frontal lobe

1. Cerebellum to occipital lobe

1. glomeruli (in olfactory bulb and in CNS)
2. piriform cotex, olfactory tubercle, amygdala, entorhinal cortex
3.hypothalamus from amygdala, hippocampus from entorhinal cortex
4. thalamus to orbitofrontal cerebral cortex

The olfactory system involves specific pathways and locations for the transmission of signals related to smell. The incorrect answers provided do not correspond to the actual synapse locations within the olfactory system as outlined in the correct answer.

Explanation

The olfactory system involves specific pathways and locations for the transmission of signals related to smell. The incorrect answers provided do not correspond to the actual synapse locations within the olfactory system as outlined in the correct answer.

17. Describe the mapping of olfactory stimuli responses across the glomeruli of the olfactory bulb.

Each glomeruli can receive multiple axons from the same olfactory receptor neuron, causing redundancy in stimulus processing.

Glomeruli receive axons from only one olfactory receptor neuron, which results in lack of diversity in odor perception.

Each glomeruli receive axons from multiple olfactory receptor neurons, leading to overlap in responses.

*each glomeruli receive axon from one olfactory receptor neuron
-glomeruli may receive 30 axons, but it'd be from 30 different olfactory receptor neurons

The correct answer explains that each glomeruli receives axons from different olfactory receptor neurons, allowing for a wide range of odor detection. The incorrect answers suggest scenarios that are not accurate in describing the mapping of olfactory stimuli across glomeruli.

Explanation

The correct answer explains that each glomeruli receives axons from different olfactory receptor neurons, allowing for a wide range of odor detection. The incorrect answers suggest scenarios that are not accurate in describing the mapping of olfactory stimuli across glomeruli.

18. How does the relative olfactory sensitivity vary in different mammals, and what anatomical correlation is associated with this sensitivity?

Mammals with lower olfactory sensitivity typically have more olfactory receptors.

Olfactory sensitivity in mammals is not related to the number of olfactory receptors.

Mammals that have more olfactory sensitivity have a lot more receptors.

Mammals with higher olfactory sensitivity have smaller olfactory bulbs.

Olfactory sensitivity in mammals is directly correlated with the number of olfactory receptors, with more receptors leading to higher sensitivity.

Explanation

Olfactory sensitivity in mammals is directly correlated with the number of olfactory receptors, with more receptors leading to higher sensitivity.

19. Name the layers of the cornea. Which layer is reshaped during LASIK surgery to change corneal focusing?

Epithelium

Descemet's membrane

*epithelium, bowman's membrane, stroma, descemet's membrane, endothelium
*stroma can be reshaped by lasek surgery if thick enough

Endothelium

During LASIK surgery, the stroma layer of the cornea is reshaped to correct vision.

Explanation

During LASIK surgery, the stroma layer of the cornea is reshaped to correct vision.

20. Name the 6 neuronal cell types of the retina.

1. glial cell 2. pyramidal cell 3. Purkinje cell

1. rod
2. cone
3. horizontal cell
4. bipolar cell
5. amacrine cell
6. ganglion cell

The incorrect answers provided do not represent neuronal cell types found in the retina. Glial cells are support cells, pyramidal cells are found in the cerebral cortex, and Purkinje cells are found in the cerebellum.

Explanation

The incorrect answers provided do not represent neuronal cell types found in the retina. Glial cells are support cells, pyramidal cells are found in the cerebral cortex, and Purkinje cells are found in the cerebellum.

21. Distinguish between macular degeneration and retinitis pigmentosa.

1. Retinitis pigmentosa: degenerating cone photoreceptors in fovea, happens in old people. 2. Macular degeneration: degeneration of rod photoreceptors in periphery in children.

1. retinis pigmentosa: degenerating rod photoreceptors in periphery in children, pigment epithelium invade retina because of degenerating photoreceptors
2. macular degeneration: degeneration of cone photoreceptors in fovea, happens in old people

1. Retinitis pigmentosa: degeneration of both rod and cone photoreceptors in fovea, happens in old people. 2. Macular degeneration: degeneration of both rod and cone photoreceptors in periphery in children.

1. Retinitis pigmentosa: degeneration of cone photoreceptors in fovea, happens in old people. 2. Macular degeneration: degenerating rod photoreceptors in periphery in children.

Retinitis pigmentosa primarily affects rod photoreceptors in the periphery and occurs in children, while macular degeneration specifically targets cone photoreceptors in the fovea and is more common in older individuals.

Explanation

Retinitis pigmentosa primarily affects rod photoreceptors in the periphery and occurs in children, while macular degeneration specifically targets cone photoreceptors in the fovea and is more common in older individuals.

22. Describe the signaling cascade and electrophysiological responses in rod and cone photoreceptors. What accounts for the adaptive response in cones?

3. The adaptive response in cones is primarily due to the absence of opsins and rhodopsin in their photoreceptors.

1. Opsin and rhodopsin receptors are activated when their ligand changes from 12-trans retinal to 11-cis retinal in the absence of light.

1.opsin and rhodopsin (GPCRs) receptor are activated when their ligand Retinal changes from 11-cis retinal to 12-trans retinal when exposed to light
2. the 3 opsins and rhodopsin absorb light (hyperpolarize) and activate transducin via GCPR
3. transducin activates phosphodiesterase, which decreases cGMP levels
- closes ion channels letting in sodium and calcium
-calcium presence lowers guanylate cyclase (which makes cyclic GMP)

2. Transducin decreases cGMP levels, which opens ion channels and increases sodium and calcium influx.

The correct answer details the activation of opsins and rhodopsin in response to light exposure, leading to changes in cGMP levels and ion channel activity. The incorrect answers misinterpret the mechanisms involved in the signaling cascade and adaptive responses in cones.

Explanation

The correct answer details the activation of opsins and rhodopsin in response to light exposure, leading to changes in cGMP levels and ion channel activity. The incorrect answers misinterpret the mechanisms involved in the signaling cascade and adaptive responses in cones.

23. What is the basis for the different responses in ON and OFF bipolar cells?

ON bipolar cells hyperpolarize when glutamate release is decreased, while OFF bipolar cells depolarize.

*depolarize (off) or hyperpolarize (on) when glutamate release is decreased
*giving off bipolar cell more glutamate will depolarize
*ON bipolar cell is like a photoreceptor from going light to dark b/c cGMP activity increases

They both depolarize in response to increased glutamate release.

ON and OFF bipolar cells exhibit the same response to changes in glutamate release.

24. What is the detailed retinal circuitry that results in the center surround responses in ganglion cells?

Ganglion cells have individual preferences for either on or off center responses regardless of bipolar cell input.

The center surround responses in ganglion cells are solely determined by the number of synapses involved in the retinal circuitry.

*on center fires a lot more when stimulus is in middle of its receptive field
*off center fires a lot more when stimulus surrounds the middle of its receptive field
*regards to circuitry: bipolar receptor cells respond differently to glutamate, but ganglion cells respond the same. so bipolar cells are what make ganglion cells on or off center

Photoreceptor cells respond directly to stimulus in the center of their receptive field.

25. What are the two most common types of dichromatic color blindness?

Monochromacy (single-color perception), Cone monochromacy (only one functioning cone type)

Tritanopia (loss of S opsin), Anomalous trichromacy (defective L or M opsin)

Protanopia (loss of L opsin), Deuteranopia (lose of M opsin)

Dichromacy (complete color blindness), Achromatopsia (total color blindness)

Dichromatic color blindness refers to the loss of one type of cone photoreceptor, leading to difficulty in distinguishing colors. The correct answer includes Protanopia and Deuteranopia, which involve the loss of L or M opsins, respectively. The incorrect answers provide other types of color vision deficiencies that do not match the most common dichromatic conditions.

Explanation

Dichromatic color blindness refers to the loss of one type of cone photoreceptor, leading to difficulty in distinguishing colors. The correct answer includes Protanopia and Deuteranopia, which involve the loss of L or M opsins, respectively. The incorrect answers provide other types of color vision deficiencies that do not match the most common dichromatic conditions.

26. What are the circuitry implications (genetically predetermined or learned) of the demonstration of successful gene therapy for dichromatic color blindness in primates?

Mixed

Learned

Read

Not significant

The circuitry implications of gene therapy for dichromatic color blindness in primates are primarily genetically predetermined as the therapy targets specific genetic defects responsible for the color blindness. Although some components of learning may come into play during the process, the main focus is on correcting the genetic mutation.

Explanation

The circuitry implications of gene therapy for dichromatic color blindness in primates are primarily genetically predetermined as the therapy targets specific genetic defects responsible for the color blindness. Although some components of learning may come into play during the process, the main focus is on correcting the genetic mutation.

27. Describe the ipsilateral and contralateral projections from each eye, and explain how lesions in different parts of the visual pathway would impair vision. Also, identify the parts of the visual field transmitted by inferior and superior projections to the visual cortex.

Lesions before the optic chiasm always result in vision loss in both eyes.

All layers in the LGN receive input from both eyes equally.

Layers in the LGN either receive input from ipsilateral or contralateral eye. they don't miss.
* 3 layers are for ipsilateral eye, 3 other layers are for contralateral eye
*lesions before the optic chiasm will affect the eye of origin, but lesions after optic chiasm will affect opposite eye

There are only two layers in the LGN, one for each eye.

The correct answer specifies the segregation of input in the LGN, the effect of lesions on vision based on location, and the number of layers dedicated to each eye. The incorrect answers provide misleading information that contradicts established knowledge in the field of vision and visual processing.

Explanation

The correct answer specifies the segregation of input in the LGN, the effect of lesions on vision based on location, and the number of layers dedicated to each eye. The incorrect answers provide misleading information that contradicts established knowledge in the field of vision and visual processing.