study guide qs exam 2 Flashcards
- How increasing intensity of sensory stimuli is encoded by action potentials and receptor potentials?
AMPLITUDE reflects the intensity of the stimulus
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.
- The function of Aβ afferent fibers
CONVEY TOUCH SENSATION
- Slowly and rapidly adapting somatic sensory afferent fibers provide which types of information
SA Afferents- size and shape of the object
sense points, edges, and curvature
merkel
objects moved across skin
messier corpuscles
skin vibration
pacininan
skin stretch
Ruffini corpuscles
function to sense skin indentation in hairy skin
touch domes
sense skin stroke
circumferential endings
to sense direction-selective hair deflection and gentle caress.
longitudinal lanceolate
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
3a responds to
proprioceptors
2 responds to both
tactile and proprioceptive stimuli
3b and 1 respond to
cutaneous stimuli
partial deficits- inability to discriminate the size and shape of objects
2
Profound deficits in all tactile sensations
3b
dorsal column arise from
mostly axons from the first order DRG neurons
Dorsal Column location of crossing midline
Brainstem or cervical spinal cord
anterolateral column arised from what
2nd order dorsal horn neurons in spinal cord
location of crossing midline in anterolateral column
spinal cord
which of the following is not involved in the affective motivation
somatosensory cortex
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
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
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?
- detect luminance
- light adaptation
light adaptation is achieved by which two mechanisms in the retina
- decreasing intracellular ca2+
- 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
- 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
- Gof
- adenyl cyclase
- cyclic nucleotide gated channels
- ca2+ activated cl- current vg na+ channels
- 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
NA
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
t
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
- pain and itching (nocicpetion)
- cold and heat (thermoception
- sweet
- umami
- bitter
hair cells use what channel
MET
What is in common between the olfactory epithelium and taste buds
both use basal cells
