How is a nerve impulse initiated, and what is the role of the threshold potential in this process?

What occurs when presynaptic neurons are depolarized, and how do they release neurotransmitters into the synapse?

What is the function of synapses, and how do they serve as junctions between neurons and other cells like receptors or effector cells?

How do local currents contribute to the propagation of nerve impulses along an axon, and how does the threshold potential come into play?

How do nerve impulses propagate along the axons of neurons, and what is their relationship with action potentials?

What happens during the depolarization and repolarization phases of an action potential?

How do neurons pump sodium and potassium ions across their membranes to generate a resting potential?

What is myelination, and how does it allow for salutatory conduction of nerve impulses?

How do neurons transmit electrical impulses, and what role do they play in communication within the body?

How have epidemiological studies contributed to our understanding of the causes of lung cancer?