Neuronal communication GapFill

The nervous system consists of a series of interconnecting pathways which respond to changes in the environment, called  sensessynapsesimpulsesstimuli. Pathways generally consist of a receptor, a  musclecoordinatorcleftfibre and an effector. The nervous system uses  bloodlymphneuroneshormones to pass electrical impulses around the body.

At rest, the inside of an axon is more  positively chargedacidicbasicnegatively charged than the outside, but when a stimulus generates  a resting potentialan action potentiala positive potentialan ionic potential, the membrane is depolarised.  Local currentsMyogenic draughtsTransient circuitsCyclic potentials may also be generated by the sideways movement of ions along a neurone towards areas of lower concentration.

A Pacinian corpuscle changes its permeability to  chloridepotassiumsodiummagnesium ions when it is stretched, and voltage-gated ion channels cause an influx of the ions when a generator potential is created. The membrane is repolarised by moving  hydrogenlithiumcalciumpotassium ions back out of the membrane.

In myelinated neurones, impulses can only pass between  bundles of Hisnodes of Ranvierstem cellsislets of Langerhans, which lack Schwann cells. This is called  a frame shiftkinesissaltatory conductionthe polymerase chain reaction.

Signals are passed across synapses using  red blood cellsneurotransmitterswhite blood cellssynaptic vesicles. At cholinergic synapses,  acetylcholineglycogenthymineadenosine triphosphate is stored in  capsulesnucleitRNAvesicles in the presynaptic knob and can diffuse across the synaptic cleft to bind to receptors on the postsynaptic membrane, which passes the signal to the next neurone.