Neurones Flashcards
Define the resting state
Both sodium and potassium channels are closed and the resting potential is maintained
Define the rising phase of the action potential
Depolarisation opens most sodium channels.
The sodium makes the inside of the membrane positive with respect to the outside
Define depolarisation
A stimulus opens some sodium channels.
Sodium influx depolarises the membrane.
If it reaches the threshold, an action potential is triggered
Define the falling phase of the action potential
The sodium channels close.
Potassium channels open to allow the potassium to leave making the inside negative
Define the undershoot
Potassium channels begin to close to return the membrane to its resting state
What are sensory receptors?
Specialised cells that are energy transducers
What is the role of a sensory receptor?
Detects stimuli and causes a generator potential
What is an energy transducer?
They convert information into a signal that the brain can understand
What do photoreceptors detect?
Light
What do chemoreceptors detect?
Chemical changes
What do thermoreceptors detect?
Temperature
What do mechanoreceptors detect?
Physical movement
What do proprioreceptors detect?
Position/movement
What is the parcinian corpuscle?
A mechanoreceptor that detects pressure and vibrations
Describe the structure of the parcinian corpuscle
Layers of connective tissue separated by viscous gel with stretched mediated sodium channels
