Sensory System Flashcards
What is the sensory system?
It is part of the nervous system which give organism information about the external world and the organism internal state
For each sense stated below please name the system and the type of receptor that is needed to detect the sense in the system.
Hearing
Sight
Taste
Smell
Touch
Balance
Vibration (fish, frogs)
Electric (electric fish, platypus)
Heat (Snake)
Magnetic
Hearing; Auditory System; Hair cells
Sight; Visual System; Photoreceptor
Taste; Gustatory System; Taste Buds
Smell; Olfactory System; Olfactory receptor
Touch; Somatosensory; free nerve ending
Balance; Vestibular; Hair Cells
Vibration; Lateral line system; Hair Cells
Electric; Electric System; Electrorecptors
Heat; Infra-Red System; Infra-Red receptors
Magnetic; Magnetic; Magnetoreceptors
What is Transduction?
Singal from the environment must be transformed into neuronal activity.
The first step in perception of a stimulus
Sensory receptor cells have mechanisms which act either _____ or ________ to either open or close ion channels.
Directly; Indirectly
True or False: Receptor potential is different from post-synaptic potentials.
False
Receptor potential are very similar to postsynaptic potentials
What is the general effect of either opening or closing ion channels?
Change in membrane potential
Receptor potentials are ________, meaning the larger the magnitude of the stimulus the larger magnitude of the receptor potential
Graded –> does not trigger A.P.
What is Modality?
Sensory modality refers to the type of information encoded by a receptor.
Receptors are selective for particular modularity.
What are examples of receptors are selective for a particular modality?
Hint: Visual System, Somatosensory System
Why is modality important?
Photoreceptors in our eyes are sensitive to light but will not respond to sound.
Dorsal Root Ganglion cells will respond to touch on the skin, but will not respond to light shining on the skin.
The active cells tells the brain what sort of stimulus is present.
Different receptors within a given sensory system can be ____________ in terms of what ____________.
Very specific; what stimuli they respond to.
What are some examples of the species of different receptors in different systems?
Different photoreceptors respond to different wavelengths of light. This allows us to see different _______.
Different cochlear hair cells respond to different frequencies of sound, which allows us to hear different __________.
Different dorsal root ganglion cells respond to different stimuli allowing us to feel _____________.
Colors
Pitches
touch, pain, and temperature
What is Turning Curves used for?
Used to determine a neuron’s selectivity for different stimuli.
To plot a cell response vs a physical feature of a stimulus
The size of a receptor potential depends on the ________ of a stimulus.
Which receptor potential will generate more A.P.?
Intensity
Larger intensity
What are the two ways that the duration of a stimulus can be encoded?
(i) Sensory neurons with tonic responses continue to fire as long as the stimulus is present
(ii) Sensory neurons with phasic responses adapt to the stimulus – they fire only when the stimulus is turned on or in some cases also when the stimulus is turned off.
True or False: Phasic responses rely on habituation. Since habituation is common, sensory neurons with phasic responses (adaptation) are common in a higher level of the brain.
True
True or False: Sensory receptors tend to be organized in a 2-D sensory receptor sheet.
True
True or False: Only a few sensory cells encode the location of a stimulus by having a receptive field.
False
All sensory cells ( sensory receptors, but also all of the CNS neurons) encode the location of a stimulus by having a receptive field.
True or False: A sensory cell’s receptive field is the location within the sensory receptor sheet in which the cell responds to stimuli.
True
What are the maps?
Forms of the major organizing principle of the sensory system are that neurons in sensory areas of the sensory receptor sheet.
If cells at location A are firing, what part of the body is being touched?
Thumb
If cells at location C are firing, what part of the body is being touched?
Face
Sensory maps tend to maintain ______________; cells next to each other in the brain tend to have receptive fields next to each other on the receptor sheet.
Nearest neighbor relationship
Sensory maps are not perfect maps of the sensory sheet in that certain parts of the maps are __________.
Magnified
Which parts of the somatosensory map are magnified?
Face, hand, foot ,tongue
True or False: Map magnification has perceptual consequences.
True
Do you think we are better or worse at discriminating touch on our finger which is magnified on the map or on our trunk which has less brain processing it?
Finger, the more brain the better you can process information
What kind of receptive fields would the visual system correspond to?
Corresponding to a particular location on the retina
What would happen if the adapting cells had a huge receptive field covering the entire retina?
See a red blur
