4 - Sensory receptor Flashcards
Sensory neurons are _____________ neurons with the cell bodies situated in the dorsal root ganglion
unipolar/pseudounipolar
Based on the location of the receptors, receptors can be divided into which 3 types? Briefly explain each type of receptor.
- Exteroceptor: located at body surface to provide surface information
- Proprioceptor: located at muscles, tendons, joints to provide the positional information
- Interoceptor: located inside the body to provide internal information
Special Sense: taste, equilibrium, sound, sight, smell
Statement T/F ?
Hair cell contains mechanoreceptor which are both Special receptor and proprioceptor
T
Only applies to hair cells for sensing the equilibrium only
Based on energy form, receptors can be divided into which 5 types? Briefly describe them.
- Mechanoreceptors: touch, pressure, sound, proprioception (The ability to sense stimuli arising within the body regarding position, motion, and equilibrium)
- Photoreceptors: light
- Chemoreceptors: blood gases, pH, taste, smell
- Thermoreceptors: warm, coldness
- Nocireceptors: (thermal, mechanical, chemical, polymodal (different form of energy) (a sensory neuron that responds to damaging or potentially damaging stimuli by sending “possible threat” signals to the spinal cord and the brain)
Based on structural form of receptors, they can be divided into which 2 receptors?
- Primary receptor:
Sensory nerve ending as receptor that directly detect the stimuli (Free or encapsulated) - Secondary(complex) receptor:
Separate receptor cell synapse with the first-order sensory neuron
What is transduction?
Process whereby the sensory receptor converts energy of a sensory stimulus into opening or closing of ion channels in the receptor membrane (receptor/ generator potential)
What does a sensory unit contain?
A single sensory nerve +
all the receptors associated with it.
DOES NOT include the receptor field
What is the difference between primary and secondary receptive field?
Primary receptive field: Area on which adequate stimuli could produce response in a sensory neuron;
Secondary receptive field: Primary sensory neurons converge on the same secondary sensory neuron, and their respective primary receptive field are merged.
Secondary sensory neuron transmits signals from ______ to _________.
Tertiary sensory neuron: to _______.
spinal cord; thalamus
cortex
When many primary neurons are converged on a single secondary neuron, the secondary receptive field is large. If 2 stimuli are made on that area, they will be perceived as one. This condition is named ____________.
Two-point discrimination
In fingers, there are small receptive field, less two-point discrimination
What is referred pain?
When visceral and somatic sensory afferents converge to the same segmental level of the spinal cord on the
same secondary sensory neurons.
What code for the intensity of stimulus?
- Frequency of AP
(NOT by amplitude as they are of the same size) - Number of sensory nerves/ sensory units recruited to respond.
____________ is indicated by a decreases in magnitude of the receptor potential over time in the presence of a
constant stimuli.
Receptor adaptation
DIFF FROM:
“Accommodation” refers to the decline in excitability (due to increased
threshold) of a neuron with a slow gradual depolarization or prolonged
depolarization (e.g. hyperkalaemia).
What are the differences between phasic and tonic receptors?
Phasic: rapidly adapt to a constant stimulus and turn off.
Tonic: slowly adapting receptors that respond for the duration of the stimulus.
_________ enhances contrast between sites of strong and weak stimulus. At the primary sensory neurons, the intensity of the is proportional in each receptor field. ___________ reduces the collateral signal transmission.
Lateral inhibition;
Secondary sensory neuron
