Receptors: Pacinian Corpuscle Flashcards
What pressure does the Pacinian corpuscle respond to?
Pacinian corpuscles respond to changes in mechanical pressure
What are two features of every sensory receptor, like the Pacinian corpuscle?
link back to the Pacinian corpuscle
1) Sensory receptors only to a single type of stimulus - the Pacinian corpuscle responds specifically to mechanical pressure
2) Sensory receptors produce a generator potential by acting as traducers - the Pacinian corpuscle transduces the mechanical energy of the stimulus into a generator potential
Where is the Pacinian corpuscle mainly found ?
The Pacinian corpuscle is mainly found deep in the skin, mainly the fingers, soles of the feet and the external genitalia
What is the structure of a Pacinian corpuscle?
The Pacinian corpuscles has a single sensory neuron at the centre of layers of tissue (called lamellae), each separated by a gel
How does the structure of the Pacinian corpuscle transduce the mechanical energy of a stimulus into a generator potential?
The sensory neurone ending at the centre of the Pacinian corpuscle has a special type of sodium channel in its plasma membrane, which are called STRETCH - MEDIATED SODIUM CHANNELS
Why is the Pacinian corpuscle sodium channel called the stretch - mediated sodium channel?
The Pacinian corpuscle has it sodium channels’ called ‘stretch - mediated sodium channels because the channels will only open and allow sodium ions to enter the sensory neuron when they become deformed, stretched
How does Pacinian corpuscle function?
1* In the normal (resting) state, the stretch - mediated sodium channels of the membrane are too narrow to allow sodium ions to pass through them. In this state, the neurone of the Pacinian corpuscle has a resting potential
2* When pressure is applied to the Pacinian corpuscle, the lamellae becomes deformed and stretches the membrane
that is around the neurone
3* This stretching widens the sodium channels in the membrane and sodium ions diffuse into the neuron
4* The influx of sodium ions changes the potential of the becomes, making it depolarised, through this a generator potential is produced
5* This generator potential in turn creates an action potential (nerve impulse) that passes along the neuron and then through other neurons to the central nervous system
What happens when a large stimulus is applied to the Pacinian corpuscle?
The greater the stimulus the more sodium ion channels are opened
