Pacinian corpuscles

What are receptors?

A cell (or protein on cell-surface membrane) that detects stimuli. They allow us to respond to changes in external and internal environments.

Are receptors specific?

Yes- they usually only respond to one type of stimulus which allows us to distinguish between different types of environments.

What are Pacinian corpuscles?

Pressure receptors are found in the skin. They are large compared to other receptors and consist of many layers of membrane around the axon on the sensory neurone.

What is the role of channel proteins in Pacinian corpuscles and why is this important for the cell?

Facilitated diffusion, which allows larger and non-lipid soluble molecules to pass through the phospholipid bilayer (e.g., glucose moving from epithelial cell to blood).

Describe the structure of a Pacinian corpuscle.

The corpuscle is oval-shaped with a series of rings of concentric connective tissue, wrapped around the end of a nerve cell. The tissue contains stretch-mediated Na+ channels.

How do Pacinian corpuscles work (seven steps)?

1: excess of Na+ ions outside of the axon.

2: Pressure on the PC increases and layers around the axon are distorted.

3: Stretch-mediated Na+ ion channels open.

4: Na+ moves into the axon via FD.

5: This changes the electrical potential difference across the axon membrane as the axon becomes more positively charged.

6: This triggers nerve impulse along the axon to the CNS.

7: This nerve impulse is called generator potential as the change in electrical potential is when the receptor is stimulated.