Pancin Corsples Flashcards
What are Pacinian corpuscles?
Mechanoreceptors that detect pressure and vibration in the skin.
What is the function of Pacinian corpuscles?
They act as transducers, converting mechanical stimuli into electrical nerve impulses.
Where are Pacinian corpuscles primarily found?
Deep in the skin, mainly in hands, feet, and joints.
What is the structure of a Pacinian corpuscle?
Made up of layers of connective tissue and contains a sensory neurone at its center.
What type of channels are present in the neurone’s membrane of a Pacinian corpuscle?
Stretch-mediated sodium (Na⁺) ion channels.
What happens to Na⁺ channels in the resting state of a Pacinian corpuscle?
Na⁺ channels are closed.
What is the resting potential of a neurone in a Pacinian corpuscle?
-70mV, inside is more negative than outside.
What occurs when pressure is applied to a Pacinian corpuscle?
The layers of connective tissue deform, causing Na⁺ channels to open.
What is the result of Na⁺ ions diffusing into the neurone?
The inside becomes less negative, leading to depolarisation.
What is the threshold potential that must be reached to generate an action potential?
-55mV.
What happens after an action potential is generated in a Pacinian corpuscle?
The impulse travels along the sensory neurone to the CNS.
What occurs after the stimulus stops in a Pacinian corpuscle?
The Na⁺ channels close, the neurone repolarises, and returns to resting potential.
What is the role of Pacinian corpuscles as transducers?
They convert pressure into an electrical signal (nerve impulse).
What do Pacinian corpuscles respond to?
Only to mechanical pressure, not heat or light.
How does greater pressure affect the function of Pacinian corpuscles?
It causes more Na⁺ channels to open, leading to stronger signals.
What is the adaptation feature of Pacinian corpuscles?
They stop responding to constant pressure and only detect changes in pressure.
List key features of Pacinian corpuscles.
- Location: Found in skin, fingers, joints, soles of feet
- Stimulus Detected: Pressure and vibration
- Type of Receptor: Mechanoreceptor
- Resting Potential: No pressure = Na⁺ channels closed
- Depolarisation: Pressure opens Na⁺ channels
- Action Potential: If threshold is reached, action potential is generated
- Adaptation: Stops responding to constant pressure.
True or False: Pacinian corpuscles can detect heat and light.
False.
How does a Pacinian corpuscle generate an action potential?
Pressure deforms the layers → Stretch-mediated Na⁺ channels open → Na⁺ diffuses in → Depolarisation occurs → If threshold is reached, an action potential is generated.
Fill in the blank: Pacinian corpuscles detect ______ in the skin.
pressure
Fill in the blank: Pacinian corpuscles contain ______ channels that open when deformed.
stretch-mediated Na⁺
Fill in the blank: Greater pressure causes more Na⁺ channels to open, leading to ______ signals.
stronger
