L56. Senses and Perception Flashcards
A stimulus is converted to an electrical action potential by what?
Specific sensory receptors.
What ensures signals are transmitted correctly?
Specific sensory pathways.
Receptors only respond to specific stimuli. Give the term for this.
Modality specific.
Give an example of :
a stimulus
its receptor
its sensation
Stimulus - Mechanical
Receptor - Mechanoreceptor
Sensation - Touch
Describe the relationship between neurons and receptors.
Neurons have peripheral nerve branches each with a nerve ending, called a receptor.
What is a receptive field?
The distribution of nerve endings (receptors)
Are all receptive field sizes the same?
Receptive field sizes differ in the body and some overlap.
Describe the difference in size between receptive fields in the periphery and trunk.
Receptive fields are small in the periphery (fingers) and larger in the trunk (arms).
What does high sensitivity mean in relation to receptive fields?
High sensitivity = high density of receptive fields.
Describe the receptive field size of an area with a small 2-pont discrimination.
Small receptive fields.
Transduction stimulus pathway :
- Stimulus
- Change in receptor permeability
- _______________________
- _______________________
- Action potential
Transduction stimulus pathway :
- Stimulus
- Change in receptor permeability
- Influx of cations
- Depolarisation
- Action potential
What does Ionotropic mean?
There is a direct pathway through the channel
Which take longer to open : G protein coupled receptors or ionotropic channels?
G protein coupled receptors
What 2 factors control stimulus intensity?
- Frequency of Action Potential (greater stimulus = greater AP frequency)
- Numbers of neurons activated
Describe the 2 types of stimulus duration.
Slowly adapting (present at start and continues throughout stimulus, slowing down)
Rapidly adapting (present only at the start)
