What is the difference between a nerve fiber and a nerve?

A nerve fiber is the axon of a single neuron. Bundles of these fibers are called nerves in the peripheral nervous system (PNS) and tracts in the central nervous system (CNS).

What are the two main types of nerve fibers?

The two main types are myelinated fibers and nonmyelinated fibers.

How does myelination differ between the CNS and PNS?

In the PNS, Schwann cells myelinate axons, forming a myelin sheath and neurilemmal sheath. In the CNS, oligodendrocytes myelinate multiple axons at once.

What is saltatory conduction and how does it work?

Saltatory conduction is the process where an action potential jumps between nodes of Ranvier in myelinated fibers, increasing transmission speed compared to continuous conduction in nonmyelinated fibers.

What is a synapse and what are its key components?

A synapse is a junction for nerve impulse transmission between neurons. Its key components include the presynaptic knob with neurotransmitters, synaptic cleft (20–30 nm gap), and postsynaptic membrane with receptors.

What is the role of neurotransmitters in synaptic transmission?

Neurotransmitters like acetylcholine are chemicals released into the synaptic cleft to bind receptors on the postsynaptic membrane, triggering depolarization or hyperpolarization for excitatory or inhibitory effects.

What are examples of myelinated and nonmyelinated fibers?

Examples include myelinated fibers like large somatic fibers and all preganglionic ANS fibers, and nonmyelinated fibers like small somatic fibers and all postganglionic ANS fibers.

Nerve Fibers & Synapses – Myelin and Transmission

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