Neurons and Synapses

Neonicotinoids are agonists that bind to nicotinic acetylcholine receptors. By binding to these receptors, they cause overstimulation and eventually block synaptic transmission at cholinergic synapses in insects.

Acetylcholinesterase is the specific enzyme located in the synaptic cleft that hydrolyzes acetylcholine into choline and acetate.

When the presynaptic membrane depolarizes, voltage-gated calcium channels open, leading to an influx of calcium which triggers the exocytosis of neurotransmitters into the synaptic cleft.

Local currents flow from an active region to an adjacent inactive region, causing the membrane potential in the inactive region to rise until it reaches the threshold potential, triggering a new action potential.

During repolarization, voltage-gated potassium channels open, allowing K+ ions to flow out of the axon down their concentration gradient via facilitated diffusion.

During depolarization, voltage-gated sodium channels open, allowing Na+ ions to rush into the axon down their concentration gradient via facilitated diffusion.

An action potential is defined by the rapid change in membrane potential consisting of the depolarization phase (rising) and the repolarization phase (falling).

The sodium-potassium pump maintains the resting potential by actively transporting 3 Na+ ions out of the cell and 2 K+ ions into the cell using ATP.

Myelin sheaths act as insulators that allow the action potential to jump between nodes of Ranvier, a process known as saltatory conduction.

Neurons are specialized cells designed to transmit electrical impulses (action potentials) along their axons to communicate information.