Peripheral nervous system query

I'm writing my A2 Biology coursework at the minute and am including some information on the PNS.

I'm curious as to why impulses can jump from across schwann cells from one nerve of ranvier to another yet not jump across a synapse.

Is the gap across a synapse really that much bigger than the length of a schwann cell?

node of ranvier

The axon of the peripheral nerve continues inside the schwann cell, so the transmission of impulses is still along the length of one cell. At the synapse you are transmitting between cells.
The synapse is much smaller than the length of a Schwann cell along the length of a neuron.
At the nodes of ranvier, the depolarisation of a nearby node is sufficient to open voltage gated ion channels depolarising the membrane here.

Does that answer your question?

I know it's a bit late now but - it doesn't actually jump. It's just reinforced at the Nodes of Ranvier when more ion channels open. "Jumping from node to node" is terminology specifically designed to confuse students by evil and twisted examiners.

Yeah I thought so ... knew it didn't make sense and our teacher couldn't explain it

Yes that answers the question I think - the impulse an never jump across an air gap basically ... BUT - I was never happy with how impulses actually jump across the nodes (I can give a hand-waiving explanation but it is one of the things I was never really happy with at A-level)