Sensory Physiology Flashcards
What is sensory physiology?
How sensory stimuli are transduced by sensory receptors and processed by the nervous system (afferent pathway to CNS)
What is a sensory system?
Sense organ + afferent pathway + specific area of brain
What is a sensory receptor?
Specialized cell that detects incoming sensory stimuli
What are receptor proteins?
Proteins on sensory receptors that detect incoming signals
Epithelial sensory receptor cell
Associated to an afferent neuron and relay signals through the release of neurotransmitters
Explain the sequence of signal transduction down a afferent neuron
Incoming signals received through dendrites, and action potential is generated at trigger zone (same version as axon hillock) and the AP bypasses the cell body as it travels the length of the axon before reaching the axon terminal and releasing neurotransmitters
What is the basis for sensory receptors classification?
The type of stimulus they detect (light, chemicals, etc.)
What are polymodal receptors?
Receptors that are sensitive to multiple modalities
What are the 4 steps for sensory reception?
1)Reception
2)Transduction
3)Transmission
4)Perception
What is range fractionation?
Different sensory receptors that are sensitive to different ranges of stimuli, work together to be able to perceive the intensity
What is the receptive field?
Region of sensory surface
What is lateral inhibition?
When a stimulus excites a neuron, it will inhibit the neighbouring neurons to release APs to allow for greater specifity to understand the stimulus
Difference between tonic and phasic receptors?
Tonic receptors fire APs for the entire duration of the stimulus, where phasic receptors only fire an AP at the initiation of the stimulus
Types of chemoreception
Internal & External
Vomeronasal organ
Used to capture pheromones
Flehmen response
Curving of lip to facilitate the transfer of pheromones to the vomeronasal organ
Gustation
Direct contact between chemical @ high concentrations and the animal
Olfaction
Airborne chemicals @ lower concentrations interact with animal from a distance
5 categories of taste
Umami, sweet, sour, bitter, salty
Which taste’s use G-coupled protein receptors?
Umami, sweet and bitter
Which taste’s use ion channel receptors?
Salty and sour
What would the body do when having a salt deficiency?
Trigger reuptake of aldosterone and that increase the expression of epithelial Na+ channels in the taste buds; inducing a craving
To what taste does the taste map light up and show high neural activity?
Bitter tastants
2 systems that are specialized for olfaction?
Main olfactory and vomeronasal systems
