Sioban turns around because she feels a hand on her shoulder. the process in which the receptors in the skin turn the stimulation into a neural impulse is called:

The process in which the receptors in the skin turn the stimulation into a neural impulse is called transduction. In addition, transduction is the process by which sensory input is converted to a neural code and sent to the brain. A signal in which a hormone or neurotransmitter interrelates with a receptor on the cell surface in which this contact causes a alteration in a second messenger such calcium and will eventually a alteration is activated in the function of cell. 

3. compressed spring because it have stored energy that is about to be kenotic if you released the com pressed spring

Na+ loss through sweet plus the dilution has lowered na+ concentration outside of neurons, altering the na+ equilibrium potential. sodium exists more outside the cells than inside. when na+ is lost by sweat plus the dilution( because they drink a lot of water) changes the concentration outside the cell, forcing the water to enter the cell and attempt to balance the concentration inside/outside.the problem is that the abundance of water will cause the cells to swell. most cells can adapt, however, the brain cells can't that's why the runner has confusion and can't control the muscles.  if not treated and this occurs in less than 48 hours, it can be immediately fatal .