study guide qs exam 2 Flashcards by sophia rahman

How increasing intensity of sensory stimuli is encoded by action potentials and receptor potentials?

AMPLITUDE reflects the intensity of the stimulus

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Which types of senses are mediated by dorsal root ganglion neurons

a. Sensory information such as pain, touch, vibrations, pressure.
b. Proprioceptors- sensory in muscles, tendons, joints.
c. Nociceptive- pain, temperature, coarse touch.
d. Tactile- cutaneous mechanoreceptors
. Touch, vibration, pressure.

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The function of Aβ afferent fibers

CONVEY TOUCH SENSATION

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Slowly and rapidly adapting somatic sensory afferent fibers provide which types of information

SA Afferents- size and shape of the object

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sense points, edges, and curvature

merkel

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objects moved across skin

messier corpuscles

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skin vibration

pacininan

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skin stretch

Ruffini corpuscles

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function to sense skin indentation in hairy skin

touch domes

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sense skin stroke

circumferential endings

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to sense direction-selective hair deflection and gentle caress.

longitudinal lanceolate

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Describe the central pathways conveying tactile information from the body

Dorsal root ganglia -> lateral cervical nucleus in spinal cord/dorsal column nuclei in medulla -> contralateral ventral posterior lateral nucleus in thalamus -> contralateral primary somatosensory cortex

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3a responds to

proprioceptors

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2 responds to both

tactile and proprioceptive stimuli

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3b and 1 respond to

cutaneous stimuli

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partial deficits- inability to discriminate the size and shape of objects

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Profound deficits in all tactile sensations

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dorsal column arise from

mostly axons from the first order DRG neurons

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Dorsal Column location of crossing midline

Brainstem or cervical spinal cord

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anterolateral column arised from what

2nd order dorsal horn neurons in spinal cord

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location of crossing midline in anterolateral column

spinal cord

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which of the following is not involved in the affective motivation

somatosensory cortex

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following a painful stimulus associated with tissue damage, stimuli in the injury and surrounding areas that would ordinarily be perceived as slightly painful are perceived as significantly more so (e.g. increased sensitivity to temperature after a sunburn), resulting from both peripheral and central sensitization

hyperalgesia

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induction of pain by a normally innocuous stimulus; resulting from inputs from low‐threshold mechanoreceptors to activate dorsal horn neurons (a type of central sensitization)

allodynia

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It is possible to invoke pain from innocus

yes, by allodynia

What is the neurotransmitter involved in the placebo effect for pain modulation?

Endogenous opioids

what is the gate theory of pain

activation of mechanoreceptors

What is the three-neuron chain in the retina

Photoreceptor > bipolar cell > ganglion cell

a. Photoreceptor absorbs a photon of light b. Double bond breaks and retinal changes from 11-cis to all-trans isomer c. Conformational change of rhodopsin leads to activation of a G-protein called transducin d. Transducin activates a phosphodiesterase that hydrolyze cGMP e. Lowering of cGMP concentration in the outer segment leads to channel closure and hyperpolarization of the cell.

phototransduction

very low spatial resolution (acuity) but extremely sensitive to light. i. Slow adaptation ii. High convergence iii. High sensitivity iv. Reduced resolution

rods

very high spatial resolution (specialized for acuity) but relatively insensitive to light; also allows us to see color. i. Fast adaptation ii. Low convergence iii. Low sensitivity iv. Increased acuity

cones

What is the major anatomical difference between ON-center and OFF-center bipolar cells that causes them to respond differently to light increments?

THEY USE DIFFERENT TYPE OF GLUAMATE RECEPTOR

What are the two main functions of center-surround antagonism in receptive fields of the retina?

1. detect luminance 2. light adaptation

light adaptation is achieved by which two mechanisms in the retina

1. decreasing intracellular ca2+ 2. surround antagonism from horizontal cells

what are the 2 opening btw middle and inner ear

oval and round window

tectorial and basilar mem is located where

cochlea

Spatial arrangement of where different sound frequencies are processed in different regions of the auditory system

tonotopy

22. What can the otoacoustic emission (OAE) test measure

outer hair cell función

a. 1. Displacement of the hair bundle parallel to the plane of symmetry in the direction of the tallest stereocilia stretches the tip links, opening the cation‐selective mechanoelectrical transducer (MET) channels located at the end of the link and generating a graded receptor potential to depolarize the hair cell (hair cells do not fire action potentials) b. 2. Depolarizing graded receptor potentials cause opening of voltage gated Ca2+ channels and transmitter (glutamate) release accordingly, eliciting action potentials in afferent nerve terminal of spiral ganglion neuron

mechanoelectrical transduction

cell body in perilymph or endolymph

perilymph

in scala media is K+‐rich, Na+‐poor

Endolymph

basal end of hair cell is K+‐poor, Na+‐rich

perilymph

spiral ganglion neurons

Auditory nerve

fibers terminated to the apical end of the cochlea response to low frequencies and fibers related to the basal end response to high frequencies

Tonotopy

frequency at which a given spiral ganglion neuron responds to the smallest sound intensity

Characteristic frequency

a plot of auditory threshold intensity at various frequencies for a single auditory nerve fiber

Tuning curve

specialized area that divides the hair cells into 2 populations with opposing hair bundle polarities

striola

the otolithic membrane, in which are embedded crystals of calcium carbonate; called ear stone

b. Otoconia

dome shaped gelatinous mass over hair bundles where hair bundles extend into i. Semicircular canal

capula

linear movement

utricle / saccule

rotational acceleration

semicircular canals

What is the function of the vestibulo-ocular reflex (VOR)?

Stabilizing gaze

several microvilli protrude from a single knoblike dendritic process (olfactory knob) at the apical surface of an ORN

Olfactory cilia

secret mucus- neutralizes some harmful agents

Bowman’s glands

a population of neural stem cells that divide to give rise to new receptor neurons

basal cells

provides structural support and detoxify potentially dangerous chemicals

sustentacular cells

spherical accumulations of neuropil lie just beneath the surface of the bulb and are the synaptic target of the primary olfactory axons

Glomeruli

odor transduction

1. Gof 2. adenyl cyclase 3. cyclic nucleotide gated channels 4. ca2+ activated cl- current vg na+ channels 5. na/ca2+ exchanger extrudes ca2+

What are the structural and functional features of the odorant receptor proteins? How do olfactory receptor neurons express odorant receptor genes and where do these neurons express odorant receptor proteins?

GPCR, intracellular domain, 400 of them, only one of them expresses OR function: receptor specificity

How does olfactory information transmit from sensory receptors to a cortical region? Does it require the thalamus

It does not need the thalamus. Olfactory bulbs send information to the pyriform cortex (broadly tuned) via the olfactory tract.

How is olfactory information processed by mitral cells and pyriform cortical neurons

Projection ipsilaterally via the olfactory tract

Multicellular protuberances surrounded by local invaginations (trench) in the tongue epithelium.

taste papillae

salt used what type of channel

sour uses what type of channel

OTOP1

bitter uses what type of channel

GCPR + TRPM5

umami uses what type of channel

GCPR + TRPM5

sweet uses what type of channel

GCPR + TRPM5

t/f ORNs are polarized and compartmentalized

Which of the following proteins is not involved in odor transduction

MET channel

what taste decreases intracellular proton concentration

sour

Which of the following is a commom feature of all the sesnory receptor cells

Polarized and compartmentalized

sensory epithelia for vestibular

macula for otolith organ and crista for semicircular canal

What is in common between the olfactory epithelium and taste buds

both use basal cells

what uses TRP channel

1. pain and itching (nocicpetion) 2. cold and heat (thermoception 3. sweet 4. umami 5. bitter

hair cells use what channel

MET

What is in common between the olfactory epithelium and taste buds

both use basal cells