Neurons and Synapses

Flashcards about neurons and synapses.

Central Nervous System (CNS)

The brain and spinal cord.

Peripheral Nervous System (PNS)

Peripheral nerves.

Sensory Neurons

Send signals to the CNS (afferent pathway).

Motor Neurons

Send signals from the CNS (efferent pathway).

Relay Neurons (Interneurons)

Send signals within the CNS.

Resting Potential

Polarity of a neuron at rest (-70mV).

Action Potential

Polarity of a firing neuron (+30mV).

Na+/K+ Pump

Maintains the resting potential by exchanging sodium ions (3 out) and potassium ions (2 in).

Depolarisation

The opening of sodium channels causes a sodium influx, creating a positive membrane potential.

Repolarisation

Opening potassium channels causes a potassium efflux, restoring a negative membrane potential.

Refractory Period

The ion distribution must be restored to original conditions before a neuron can fire again.

Synapses

Physical junctions between two neurons.

Neurotransmitters

Released into the synapse cleft to transmit signals.

Acetylcholine

A neurotransmitter used in the CNS and PNS.

Acetylcholinesterase

Breaks down acetylcholine in synapses.

Neonicotinoid Pesticides

Irreversibly bind to acetylcholine receptors and cannot be digested by acetylcholinesterase.

Myelin Sheath

Covers the axon in certain neurons, enabling saltatory conduction.

Nodes of Ranvier

Gaps in the myelin sheath where the action potential 'hops' for faster transmission.