3.6.1.2 Receptors - Pacinian Corpuscles

What is the primary function of a Pacinian corpuscle?

• To detect changes in temperature

• To detect mechanical pressure and vibrations

• To detect chemical changes

• To detect light

Answer explanation

Pacinian corpuscles are specialized mechanoreceptors that primarily detect mechanical pressure and vibrations, making them crucial for sensing changes in touch and texture.

Which type of ion channel is involved in the function of a Pacinian corpuscle?

• Voltage-gated calcium channels

• Ligand-gated potassium channels

• Stretch-mediated sodium ion channels

• Proton channels

Answer explanation

Pacinian corpuscles are mechanoreceptors that respond to pressure and vibration. They utilize stretch-mediated sodium ion channels to detect mechanical deformation, making this the correct choice.

What happens when a Pacinian corpuscle is stimulated?

• It releases neurotransmitters

• It establishes a generator potential

• It changes colour

• It contracts

Answer explanation

When a Pacinian corpuscle is stimulated, it establishes a generator potential, which is a change in membrane potential that can lead to the generation of an action potential, signaling sensory information.

What is the role of a generator potential in a Pacinian corpuscle?

• To initiate an action potential

• To release hormones

• To absorb nutrients

• To produce sound

Answer explanation

The generator potential in a Pacinian corpuscle is crucial for converting mechanical stimuli into electrical signals, which then initiate an action potential, allowing the nervous system to respond to pressure and vibration.

Which of the following best describes the structure of a Pacinian corpuscle?

• A flat disc

• A layered onion-like structure

• A hollow tube

• A spherical ball

Answer explanation

A Pacinian corpuscle is best described as a layered onion-like structure, consisting of concentric layers that respond to pressure and vibration, making it distinct from other shapes like a flat disc, hollow tube, or spherical ball.

What specific type of stimulus does a Pacinian corpuscle respond to?

• Chemical stimuli

• Light stimuli

• Mechanical stimuli

• Thermal stimuli

Answer explanation

Pacinian corpuscles are specialized mechanoreceptors that respond specifically to mechanical stimuli, such as pressure and vibration, making 'Mechanical stimuli' the correct choice.

How does the deformation of the Pacinian corpuscle lead to the opening of ion channels?

• By changing the temperature

• By stretching the membrane

• By altering the pH

• By releasing enzymes

Answer explanation

The deformation of the Pacinian corpuscle occurs when pressure is applied, which stretches the membrane. This mechanical stretching leads to the opening of ion channels, allowing ions to flow and generate a nerve signal.

What is the result of sodium ions entering the Pacinian corpuscle?

• Hyperpolarisation

• Depolarisation

• Repolarisation

• No change

Answer explanation

When sodium ions enter the Pacinian corpuscle, they cause depolarisation. This influx of positive ions reduces the membrane potential, making it more positive and leading to the generation of an action potential.

Which of the following is NOT a characteristic of a receptor like the Pacinian corpuscle?

• Specificity to a type of stimulus

• Ability to generate a potential

• Ability to contract

• Sensitivity to mechanical changes

Answer explanation

The Pacinian corpuscle is a mechanoreceptor that detects mechanical changes and generates potentials, but it does not have the ability to contract, which is a characteristic of muscle tissue, not sensory receptors.

What is the primary location of Pacinian corpuscles in the human body?

• In the brain

• In the skin and deep tissues

• In the eyes

• In the lungs

Answer explanation

Pacinian corpuscles are primarily located in the skin and deep tissues, where they function as mechanoreceptors that detect pressure and vibration. This makes 'In the skin and deep tissues' the correct answer.