1.2 the neuron

Dendrites: Afferent structures that receive information; the collective branches of a single neuron are called a dendritic tree.
Soma (Cell Body): Contains the nucleus for DNA transcription and rough endoplasmic reticulum for protein translation via ribosomes.
Axon: A single efferent structure that carries signals away from the cell body.
Axon Hillock and initial segment: The tapering region of the soma where the action potential is generated, and signal polarity is maintained.
Myelin Sheath: Layers of membrane providing insulation around the axon, formed by oligodendrocytes in the CNS and Schwann cells in the PNS.
Nodes of Ranvier: Gaps in the myelin sheath with high concentrations of ion channels that facilitate electrical signalling.
Axon Terminals: Extensions that release neurotransmitters, allowing communication between neurons at synapses.

Excitable: Neurons detect changes in the environment primarily through dendrites.
Conductible: Neurons generate an electrical signal called an action potential that travels along the axon in response to environmental changes.
Secretory: The electrical signal triggers the release of chemical messages called neurotransmitters at the axon terminals.

Myelinated Axons:
- Have a myelin sheath composed of multiple layers of membrane that insulate the axon.
- Action potentials propagate via saltatory conduction, where the signal jumps from node to node, resulting in faster transmission speeds.
Unmyelinated Axons:
- Lack a myelin sheath, which results in slower propagation of action potentials.
- Action potentials occur at every point along the entire exposed axon, leading to continuous conduction.

Unipolar Neurons: Single neurite extending from the soma, typically found in sensory pathways.
Bipolar Neurons: Two neurites extending from the soma, often involved in special senses such as vision and olfaction.
Multipolar Neurons: Multiple neurites, including one axon and several dendrites; the most common type found in the central nervous system.