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23 Cards in this Set
- Front
- Back
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Sensory systems |
Everything we perceive is just action potentials, we take in what we get from the environment and out brains and make use of it in the best way they can. Lines can blur and we can trick our frontal cortex-reality and perception do not line up. (Ex. Optical illusion, schizophrenia) |
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Receptor |
Sensory receptors, some are their own little component separated from the neuron, sometimes they are just a part connected. This is where the information is coming in and being measured |
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Afferent neuron (1st order neuron) |
Takes information into the central nervous system. First true sensory neuron; the axon is divided by the cell body, which lies somewhere in the middle, just outside of the spinal cord, and at that point we have crossed into the central nervous system |
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Ascending pathway (2nd order neuron) |
Job is to bring the information up the spinal cord; essentially a relay/extension cord -Doesn't go all the way up the spinal cord, just takes the information and sends it up further |
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Thalamus (3rd order neuron) |
Most sensory information goes through the thalamus, here we see that connection. Information goes into the thalamus and the thalamus distributes it to the correct cortexes |
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Cortex |
Depending on what type of signal, it goes to a different cortex |
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Organization of sensory systems |
Stimulus goes to receptors to Afferent neuron to Ascending pathway to Thalamus to Cortex |
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Types of sensory receptors (5) |
Mechanoreceptors Chemoreceptors Thermoreceptors Nociceptors Photoreceptors |
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Specificity of sensory receptors |
Each receptor is geared to respond best to a single type of signal/stimulus -A specific receptor responds to a specific stimulus -This is important to make sure the stimulus being perceived are being transmitted as specific as possible so that it is clear to the brian |
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Mechanoreceptors |
Responsive to a physical stimulus or physical change to them that generates signals to create an action potential (within normal ranges, not pain). Ex: Hair cells in the ear |
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Chemoreceptors |
Respond to some chemical change in the environment Ex. pH receptors respond to change in pH and respond accordingly |
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Thermoreceptors |
respond to temperature change Ex. In the skin |
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Nociceptors |
Respond to stimuli indicating that damage is or could be done; extreme stimuli as a warning for us |
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Photoreceptors |
Very specialized and respond to photons of light |
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Receptor sensitivity |
How sensitive the receptor is; how much stimulus will it take to trigger -Receptor "threshold": each receptor will have a threshold it has to meet before an AP will be sent from it --Low threshold=High sensitivity |
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Receptor (generator) Potentials |
Essentially the same thing as graded potentials, except they are always depolarizing, never hyperpolarizing -Ex. you can't feel a mosquito because they make a receptor potential, but don't reach threshold so you can't feel it -Our perception is not always reality because some things just dont reach threshold |
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Action potnetials |
Sent up the afferent pathway when you do reach threshold, and then you perceive that something always happens -Everything is always depolarizing because we are trying to detect what is happening in our environment, nothing will ever make it harder to detect |
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What affects sensory coding (rate of AP) |
Intensity and Duration |
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Intensity |
Number of AP per second -The more per second, the more intense the stimulus is -Lots of AP in a short amount of time when stimulus is more intense, this is how we know how strong a stimulus is, we don't have the relative refractory period |
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Duration |
Short stimulus just has AP for beginning and end -As the stimulus gets longer, there are more action potentials, but the rate stays the same. It doesn't mean a stronger stimulus, just longer stimulus |
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Receptor adaptation of duration |
Slowly Adapting (Tonic) and Rapidly Adapting (Phasic) Difference lies only with what goes on in the middle of the stimulus. They both code beginning and end, but what happens in the middle changes |
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Slowly adapting (Tonic) |
As long as the stimulus stays on, the entire duration will see action potentials |
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Rapidly adapting (Phasic) |
They want to see change, if there isn't change, they will just code the beginning until it changes again (the end) |
