Nervous System

Navigational overlay for the brain, spinal cord, peripheral nerves, and their resident cells. The nervous system is largely post-mitotic, making proteostasis collapse, mitochondrial decline, and neuroinflammation (microglial activation) the dominant aging mechanisms. The major age-related neurodegenerative diseases converge on protein-aggregation pathology layered on top of these substrates.

The system is conventionally divided into the central nervous system (brain + spinal cord) and the peripheral nervous system (cranial/spinal/autonomic nerves); both are covered here until sub-system MOCs are warranted.

Tissues & organs

• brain — the central organ; regional atrophy, white-matter changes, and aggregate pathology with age

Cell types

• neurons — post-mitotic; vulnerable to proteostasis and mitochondrial failure
• astrocytes — homeostatic support; reactive astrogliosis with age
• microglia — CNS-resident immune cells; “microglial priming”/neuroinflammation (overlap with immune-system)
• oligodendrocytes — myelinating cells; white-matter/myelin decline
• neural-stem-cells — adult neurogenesis (hippocampus); declines with age

Aging phenotypes

• neurodegeneration — the umbrella phenotype
• alzheimers-disease — amyloid-β / tau pathology
• parkinsons-disease — α-synuclein / dopaminergic loss

Key molecular axes

• Proteostasis & aggregation: loss-of-proteostasis, autophagy, tau, dkk1 (Wnt/synapse)
• Neuroinflammation: microglia, chronic-inflammation

Auto-aggregated tissue members

LIST FROM "tissues"
WHERE parent-system = "nervous-system"
SORT file.name

Missing / planned pages

• [[spinal-cord]], [[peripheral-nerve]], [[blood-brain-barrier]], [[hippocampus]], [[central-nervous-system]], [[peripheral-nervous-system]] — not yet seeded stub

See also

• by-organ-system — index of all body-system MOCs
• loss-of-proteostasis — the dominant proteostasis hallmark for post-mitotic neurons
• immune-system — microglia are the brain’s resident macrophages