Anatomy & Physiology
A practical map of the body's structures and systems
Lesson 11 of 20
Nervous system & neurons
The nervous system detects information, processes it, and coordinates responses. The central nervous system consists of the brain and spinal cord; the peripheral system includes nerves and ganglia beyond them. Neurons communicate with electrical signals along membranes and chemical signaling at many synapses. The autonomic division helps regulate involuntary functions.
Key points
- Sensory pathways carry information toward the central nervous system; motor pathways carry commands outward.
- The somatic system serves conscious sensation and skeletal-muscle control.
- The autonomic system regulates smooth muscle, cardiac muscle, and glands.
- Sympathetic activity supports mobilization; parasympathetic activity supports maintenance and recovery.
- A synapse is a communication junction between neurons or between a neuron and a target.
Key terms
- Central nervous system
- Brain and spinal cord, which integrate and coordinate information.
- Peripheral nervous system
- Nerves and ganglia outside the brain and spinal cord.
- Neuron
- Excitable cell specialized to receive and transmit signals.
- Synapse
- Junction through which a neuron communicates with another cell.
- Autonomic nervous system
- Nervous division regulating many involuntary visceral functions.
- Parasympathetic division
- Autonomic branch associated with restorative and digestive functions.
Memory tip
Afferent arrives at the CNS; efferent exits it.
Clinical note
Responses to touch vary with context, nervous-system state, and individual preference.
Unit checkpoint
Lock it in: match the terms, then test yourself.