Principles of sensory systems Flashcards
What are the 3 steps of conservation of sensory processing?
- Physical stimulus
- Transform the stimulus into nerve impulses via sensory receptors in pns
- Evoke a response to the signal in the form of perception of sensation in CNS
What is sensory transduction?
Energy is taken from the environment and converted into electrical signals
How is specificity for sensory modalities achieved?
Structure and position of the sensory receptor
What are the 5 special senses?
Vision
Smell
Taste
Hearing
Balance
Describe proprioception
Mechanical receptors attached to skin detect muscular stretch
- Allows you to understand where the body
Which modalities use mechanoreceptors?
Hearing
Balance
Touch
Proprioception
Which modalities use Chemoreceptors?
Olfaction
Taste
What modality uses a thermoreceptor?
Temperature
What modality uses a nociceptor?
Pain
What modality uses a photoreceptor?
Vision
Describe how sensory information is integrated into the CNS
Stimulus ->
Sensory receptors are activated ->
Membrane permeability is altered in sensory cell ->
Receptor potential develops in sensory cell ->
Neurotransmitter is released ->
Ap is generated in the afferent neuron terminal->
Ap propagates to CNS ->
CNS integrates the info
- Receptor potential can directly cause an ap in the sensory neuron terminal if the sensory cell and afferent nerve are the same
What are the differences between Graded receptor potentials and Action potentials?
Gps change in size due to changes in stimulus amplitude but Aps are always the same size
Aps have a threshold for activation
Describe how olfactory receptors cause direct neuronal activation
Ion influx causes membrane depolarisation
- Graded potential develops in a cilium
- Receptor potentials large enough cause depolarisation in the cell soma, triggering ap that travels to the olfactory bulb
What category of neuron would olfactory receptor fall into?
Bipolar neuron
What occurs in the dendrite of a the afferent neuron after a neurotransmitter binds to a postsynaptic receptor?
An EPSP is generated
- If the EPSP is large enough, an ap will be generated
What are the 4 types of information sensory receptors can convey?
Modality
Location
Intensity
Timing
What is the labelled line code?
The receptor is selective for one type of stimulus energy
- Axons of afferent neuron/receptor acts as a modality specific line of communication
- Axons from neurons make connections with specific areas in the CNS
Describe the receptive field of the somatic system
Region of skin innervated by the terminal of the receptor neuron
Describe the receptive field in the visual system
Region of visual field projected onto a receptor
Describe the relationship between stimulus size and receptive field
Proportional:
Large stimulus will activate a large receptive field, vice versa
Define stimulus intensity
Total amount of stimulus energy delivered to the receptor
What is the lowest stimulus strength that can be detected know as?
The sensory threshold
What is intensity determined by?
Determined by the response amplitude of the receptor and the firing frequency of afferent neurons
What is onset timing determined by?
When a stimulus energy is received by the receptor and causes it to fire
What is the stimulus duration determined by?
Adaptation rates of receptors
Describe adaptation
In response to a continuous stimuli, the firing rate of action potentials decrease
What is a tonic receptor?
A slowly adapting receptor
- Responds to a prolonged stimulation
What is a phasic receptor?
A rapidly adapting receptor
- Responds at the beginning and the end of a stimulus
