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59 Cards in this Set
- Front
- Back
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What are the neurons that respond directly to the stimuli called
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Receptors, however if a neuron requires a specific ending like a pacinian corpuscle, the ending itself will be referred to as receptor and the neuron itself will be called sensory afferent
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What is stimulus and transducer relationship
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Stimulus is recognized by a receptor cell and the receptor cell then transduces that stimulus into an electrical signal
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How do photoreceptors transducer a signal
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They do so by retinal pathway and leading to a conformation change
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How do pacinian corpuscle transducer a signal
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They are physically deformed and then they activate stretch activated channel and stimulate the DRG
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They action potential that’s generated by the receptors is called a
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Local potential, or generator potential or receptor potential and it’s different than an action potential
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How does this local potential travel
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Retrograde
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What id the mech. Of generating an action potential via a local potential
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Local potential travels backwards through the axon , if it’s great enough, it’ll bring the neuron above threshold and then the neuron will launch an AP
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What part of the neuron have voltage gated channels
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Node of Ranvier
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When the neuron extends out of the spinal chord, where does it terminate and what is located at the termination point
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It terminates peripherally and it’s usually the target
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How does a sensory neuron enter the spinal chord
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Via dorsal root to the dorsal horn
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What kind of potential is launhed at the periphery where the sensory neuron terminates
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It is a local potential, there is an influx of Na+ ions but since there are no V-gated channels, there will be no action potential
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What Is modality of a stimulus
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Vision, hearing, touch, smell
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Intensity of a stimulus
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Proportional to the strength of the stimulus
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Duration of a stimulus
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How long it lasts
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Location of a stimulus
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Where it is located, like fovea for heightened visual acuity due to greater density of the photoreceptors in that region
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What is our dorsal column made up of
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Fascilis gracillis and cuneatus
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Where does all the sensory information travel to,
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Thalamus, olfactory system
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What is thalamus
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Relay between periphery and the cortex
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What is a sensory neuron? Where are the cell bodies? Morphology? What happens with shingles?
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Sensory neuron is a pseudounipolar,has 2 processes, one travels centrally and the other travels peripherally, it resides in the DRG, shingles are caused by a virus that stays dormant in the DRG and upon activation can cause damage to arms and back
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4 distinct modalities are
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Touch(superficial and deep), proprioception (actual displacement of muscles and the joints), pain (+ by noxious stimuli, that can cause damage) and thermal (cool and warm)
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What are some of the recptors that pick up info
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Mechanoreceptors, thermoreceptors, and nociceptors
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What are mechano receptors
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These respond to actual physical deformity, bending and stretching, cutaneous and deep
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Thermoreceptors
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Respond to change in temp, hot or cold
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Nociceptors
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Respond to pain
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What are proprioceptors
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They are mechano receptors, respond to pressure
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What kind of fibers do mechanoreceptors have
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Aα and Aβ
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Is the skin uniform
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No, it we touch the skin with a cold probe and don’t hit the neurons in the cold area, we won’t feel cold, and we would only feel touch
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What kind of endings to nociceptors and thermoceptors have
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Free nerve
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What about mechanoceptors
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They all have specialized endings
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What is limb proprioception
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It is sense of position and movement of the limb, also called self vs. receptor for external stimuli
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What are some of the submodalities in propriception
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They are stationary position and the sense of limn movement (kinesthesia), these sensations are important in controlling the limb movement and evaluating the shape of an object
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Where do the axons of a-motor neurons synapse
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They synapse on the extrafusal muscle fiber nad these are called the generic lower motor neurons
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Where a intrafusal fibers located
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They are located with in the extrafusal fibers
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What nerve supply the intrafusal fibers
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Goup 1a and 2 afferents
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What kind of information is relayed the muscle spindles
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The length of the muscle, any change in the length is conveyed to the 1A or 2 fibers
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What is density of muscle spindles that supply course movemtns
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Low density
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What is the M. spindle density in areas that control the fine movements
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High density
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What kind of info is relayed by the golgi tendon organ? What kind of receptors are they? And what are they innervated by
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They do muscle tension, mechanoreceptors, and 1B
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1A fibers
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Propriceptors, musclespindle afferent, fast
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1B fibers
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Golgi tendon organ, fast, muscle tension
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Type 2 fibers
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Aβ, meisners, merckel, muscle spindle, fast but not as fast as 1α and 1β, touch and pressure
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Type 3
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Aδ, some nociceptor, they do sharp pain, thermo receptor cold
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Type 4
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C fibers, these do dull pain, warmth temp, itch, post ganglionic autonomic fibers
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What is the amplitude of the generator potential depend on
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It depends on the intensity of the stimulus
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What does the frequency of the action potential depend on
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Amplitude of the generator potential
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w/c of the following are slow and fast adopting, muscle or hair?
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The muscles are slow adapting , slow or these take longer to adapt. Hair are fast and eventually adapt
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Hwo do nociceptors detect pain
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They respond to some of the molecules that are secreted during injury like histamine, bradykinin, and K+, along with substance P. also things like prostaglandins that act directly on the sotes of the injury
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What is substance P
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It is released after an injury, it leads to vasodilation and allows mast cells to move in and + them to release histamine
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What determines whether a particular sensory neuron will respond to stimulus
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Reactive field
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What depends on reactive field
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Localization depends
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What is the receptive field of somatic sensory mechano receptor
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It is the direct area of skin that It innervates
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To feel a certain stimulus and respond to it what must happen
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You must be in the receptive field
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What is the receptive field of a highly innervated region
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It is very small, finger tip
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What is the receptive field of scarcely innervated region like you back
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It is very large. Like back
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What’s more sensitive an area with small receptive field or large
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Small
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What is a dermatome and what’s it’s use
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Is the territory that innervated by a spinal nerve, it helps in localizing the lesion
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What is 2 point threshold
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It is the distance that we need to travel to keep 2 stimuli apart
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What happens if a stimuli hits multiple receptors
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Multiple receptors will go on and be activated and send their info out to the CNS
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What is the path way to through the CNS
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All of the info that comes from the DRG neurons synapses in the spinal cord and from their ascends to the medulla, form their to the thalamus and then to the somatosensory cortex
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