Question

whats grey ramus

Answer 1

Each spinal nerve receives a branch (gray ramus communicans) from the adjacent ganglion of the sympathetic trunk.

The thoracic, and the first and second lumbar nerves each contribute a branch (white ramus communicans) to the adjoining sympathetic ganglion.

After a signal has been carried all the way from the spinal cord to ganglion through ventral ramus, they are synapsed in the ganglions and then post-ganglionic fibres carry them to the organs that they stimulate. But if the response is a whole body response, as in fight or flight, the signals are distributed to other spinal nerves by way of gray rami which serve as bridges between the spinal nerves.