Principles of Sensory Systems Flashcards
what is sensory transduction?
taking energy from the environment from the environment and changing into electrochemical signals in sensory receptors.
what type of stimulus is it called when it comes to hearing?
mechanical.
what type of stimulus is it called when it comes to balance?
mechanical.
what type of stimulus is it called when it comes to vision?
light.
what type of stimulus is it called when it comes to touch?
mechanical.
what type of stimulus is it called when it comes to temperature?
thermal.
vpain?
mechanical,
thermal,
chemical.
what type of stimulus is it called when it comes to proprioception?
mechanical.
what type of stimulus is it called when it comes to olfaction?
chemical.
what type of stimulus is it called when it comes to taste?
chemical.
what receptor detects the stimulus when it comes to hearing?
mechanoreceptor.
what receptor detects the stimulus when it comes to balance?
mechanoreceptor.
what receptor detects the stimulus when it comes to vision?
photoreceptor.
what receptor detects the stimulus when it comes to touch?
mechanoreceptor.
what receptor detects the stimulus when it comes to temperature?
thermoreceptor.
what receptor detects the stimulus when it comes to pain?
nocioceptor.
what receptor detects the stimulus when it comes to proprioception?
mechanoreceptor.
what receptor detects the stimulus when it comes to olfaction?
chemoreceptor.
what receptor detects the stimulus when it comes to taste?
chemoreceptor.
where are the receptors located when it comes to hearing?
cochlea.
where are the receptors located when it comes to balance?
vestibular system.
where are the receptors located when it comes to vision?
retina.
where are the receptors located when it comes to touch?
skin.
where are the receptors located when it comes to temperature?
skin.
where are the receptors located when it comes to pain?
skin,
internal organs.
where are the receptors located when it comes to proprioception?
muscles,
tendons,
joints.
where are the receptors located when it comes to olfaction?
nasal cavity.
where are the receptors located when it comes to taste?
tongue,
pharynx,
palate,
epiglottis.
what are the basic steps that happen when a stimulus activates a receptor protein?
membrane permeability is changed in the sensory receptor cell,
a receptor potential develops in this cell,
neurotransmitter is released onto afferent neuron terminals,
action potential is usually generated in this terminal,
action potential propagates to the CNS,
info is integrated into the CNS.
with reference to graded potentials, what happens when the stimulus is big?
the graded potential increases in size in response to the increased stimulus amplitude.
what are 2 important thongs to remember about action potentials?
they are all the same size,
and a threshold needs to be reached before they are generated.
give an example of direct neural activation (olfactory receptors):
the receptor cell is also the afferent neuron,
ion influxes cause membrane depolarisation,
a generator potential develops in cilium,
a large enough graded potential cause depolarisation on cell soma,
triggering an action potential traveling to the olfactory bulb.
give an example of receptors using a synapse (taste receptors):
the cell is different to the afferent neuron,
ion influx through channels causes depolarisation,
a graded potential develops,
initiates synaptic vesicle fusion with membrane,
neurotransmitter is released and binds to postsynaptic receptors,
this generates an excitatory postsynaptic potential (EPSP) in the dendrites of the afferent neuron,
if it is large enough an action potential is developed.
sensory receptors can covey 4 types of info:
modality,
location of stimulus,
intensity of stimulus,
timing of the stimulus.
stimulus modality is coded by the labelled line code, what is this?
the receptor is selective for one type of stimulus energy,
the axons of the receptor / associated afferent neuron acts as a modality-specific line of communication,
axons from these neurons make connections with specific areas in the CNS.
what is synaesthesia?
the labelled line code is faulty.
for stimulus modality, what does stimulating afferent neurons electrically lead to?
leads to perception of the associated sensation.
what is a receptive field in the somatic system?
the region of skin innervated by the terminals of the receptor neuron.
what is a receptive field of a photoreceptor?
is the region of the visual field projected on to that receptor.
what is stimulus intensity?
total amount of stimulus energy delivered to the receptor.
what is a sensory threshold?
the lowest stimulus strength detected.
what is stimulus intensity determined by?
the response amplitude of the receptor and thus the firing frequency of the afferent neruons.
what is onset timing?
when the stimulus energy is received by the receptor and causes it to fire.
what is stimulus duration affected by?
it is determined by the adaption rates of receptors.
what are slowly adapting receptors?
they respond to prolonged stimulation.
what are rapidly adapting receptors?
they respond at the beginning and the end of stimulus.
what divergence allow?
allow primary afferent neurons to signal to more than one relay neuron.
how is divergence useful?
useful because if something goes wrong then we aren’t losing the whole receptive field.
what does convergence allow?
ensures that relay neurons have larger receptive fields than primary afferent neurons - axons from 2 primary afferent neurons can connect to one second order neuron.
