Sensory Pathology Flashcards
What are the 3 fundamental steps in information processing?
- transduction
- transmission
- perception
What is nociception?
stimulation of nerve cells
What are the required steps of transduction?
- stimulus
- receptor w/ transducer protein present
- ion channels open or close
- membrane potentials change
- AP generation
With regard to tranduction, where does the first AP occur?
first node of Ranvier
What are the two types of receptors for sensation and how do they act?
- somatosensation: 1˚ afferent has receptors
- special senses except olfaction: receptive cells releases neurotransmitter onto 1˚ afferent
What is a receptive field?
spacial region where a stimulus will produce a response (dendrite-defined)
What is a sensory unit?
1˚ afferent + all receptive cells that define its receptor field
What is s stimulus modality?
receptors responding to one type of stimulus preferentially
What is an adequate stimulus?
stimulus TYPE that is the correct modality for a receptor to interpret
What are the three types of energy we can sense?
mechanical
chemical
electromagnetic
What is a nonadequate stimulus?
stimulus not of normal modality for receptor, may be perceived incorrectly as adequate stimulus (conditioned response)
2 ways stimulus intensity can be increased
- frequency
- population (# of cells)
Frequency coding
increased # of APs
Population coding
receptive field overlap
Tonic adaptation
slow adaptation
Phasic adaptation
fast adaptation
What is the inherent problem with acuity?
larger receptive field = decreased acuity
more receptors stimulated, less acute interpretation
Where does lateral inhibition occur?
in CNS
Describe lateral inhibition
most stimulated neurons inhibit the signal of adjacent neurons to make the localization of the sensation more acute
What is the test designed to test touch acuity?
two point discrimination test
