Sensory Systems Flashcards
What is ionotropic sensory detection?
the receptor protein itself is part of the ion channel and opens or closes the channel pore by changing its conformation
What is metabotropic sensory detection?
the receptor protein is linked to a G protein that activates a cascade of events that eventually open or close ion channels
Receptor potential
a change in the membrane potential of a sensory cell in response to a stimulus
Stretch receptor pathway
- stretching the muscle = stimulus (that opens ion channels in dendrites)
- depolarization spreads to the cell body > receptor potential
- RP spreads to the hillock (if strong enough to reach threshold > action potential triggered)
Mechanoreceptors
receptors that are sensitive to mechanical forces, involved in many sensory systems
What causes ion channels to open for sensory systems?
physical distortion of mechanoreceptor’s plasma membrane
Surface level mechanoreceptors
Merkel’s disks and Meissner’s corpuscles
Merkel’s disks
surface mechanoreceptors that adapt slowly and provide continuous information
Meissner’s corpuscles
surface mechanoreceptors that adapt rapidly and are very sensitive
Deeper mechanoreceptors
Ruffini corpuscles and Pacinian corpuscles
Ruffini corpuscles
deeper mechanoreceptors that adapt slowly and sense low frequency vibrations
Pacinian corpuscles
deeper mechanoreceptors that adapt quickly and sense high frequency vibrations
What is special about hair cells?
They are a special kind of mechanoreceptor found in the cochlea of the ear that respond to the vibration induced by sound
What are rhodopsins?
a family of photoreceptors that are composed of a pigment (retinal) bound to a protein (opsin)
What are channelrhodopsins and why are they important?
a new “optogenic” tool for stimulating neurons developed by single-called plants
Evolution of eyes
shows progression of complexity
What is an example of de-evolution?
Eastern American mole: vestigial eyes
-they don’t need to create images underground, just differentiate between light and dark
What are ommatidia?
compound eyes consisting of many optical units in arthropods; each ommatidium has a lens that directs light onto photoreceptor cells (retinula cells)