7.1 - 7.2 Flashcards
If sensory information reaches consciousness, it can be called a ___.
sensation
The chemical or energy that results in the activation of a sensory receptor is known as a(n) ___.
stimulus
Overall, the process by which a stimulus is transformed into an electrical response is known as ___ ___.
sensory transduction
A graded change in membrane voltage occurring in sensory cells in response to a stimulus is called a ___.
receptor potential
What is demonstrated by the figure of the stimulation of an afferent neuron with a receptor ending (figure 7.2)?
- Receptor potentials are graded with stimulus size.
- Action potential frequency increases with stimulus size.
T/F: All sensory signals are consciously perceived.
F
Besides modality, what other types of information are encoded by sensory receptors?
Location and intensity
In sensory physiology, the term “adequate stimulus” means ___.
the type of stimulus (modality) to which a particular receptor is most suited to respond
In general, receptors of a given sensory unit ___.
all respond to the same modality
___ is the process that converts energy from a physical stimulation into nerve impulses, which are then transmitted to the appropriate parts of the brain.
Sensory transduction
Receptor potentials that occur in sensory neurons are examples of ___ potentials.
graded
Variations in stimulus intensity can be due to which of the following factors?
- Frequency of sensory nerve fiber firing
- Magnitude of receptor potentials
- Recruitment of different numbers of afferent neurons
In myelinated sensory neurons, the site of action potential generation in response to excitatory stimulation is usually at the first ___ of ___.
node of Ranvier
The location of a stimulus is encoded mainly by ___.
which neurons deliver action potentials to the brain
What three main characteristics of a stimulus are encoded by sensory receptors?
stimulus…
- modality
- intensity
- location
Sensory acuity is the ___.
precision with which we can locate and discern one stimulus from an adjacent one
The type of stimulus, such as whether it is heat, cold, sound or pressure, is known as the stimulus ___.
modality
To test sensory acuity of an area of the body, one can apply two sharp objects to see if discrimination of the points is possible. Areas of the body with the highest numbers of sensory receptors, and the smallest receptive fields, will have the ___ sensory acuity.
highest
The conversion of stimulus energies such as pressure, light, or chemical concentration into electrical signals is referred to as sensory ___.
transduction
Which of the following does NOT influence the encoding of stimulus intensity?
duration of the stimulus
T/F: The location of all stimuli is interpreted from the place on our body where the stimulus was actually applied.
F
Which region of the body would have the greatest sensory acuity?
A region with large numbers of small sensory units
When receptive fields of adjacent sensory neurons responding to the same modality overlap, it ___ sensory activity.
increases
Stimulus intensity is coded by (1) the frequency of ___ of individual sensory units and (2) by the number of sensory units activated. This “calling in” of receptors on additional afferent neurons is known as ___.
firing; recruitment
The specific nerve fibers which send the signal to the brain determines signal ___.
location
Which is true about the frequency of action potentials propagated by sensory neurons A, B, and C, and the ability to localize the stimulus? (B overlaps A & C, but has most coverage of the stimulus)
The frequency will be highest in neuron B, helping to localize the stimulus.
