Nervous System Summary
The nervous system is responsible for detecting stimuli, transmitting signals, and coordinating responses throughout the body.
🔹 Structure
- Neuron: The basic unit, with dendrites (receive), cell body, and axon (send).
- Synapse: The gap between neurons where neurotransmitters transfer signals.
- Myelin sheath: Fatty layer that speeds up impulses.
🔹 Divisions
- Central Nervous System (CNS): Brain and spinal cord; processes and responds to information.
- Peripheral Nervous System (PNS): Nerves outside the CNS; connects CNS to limbs and organs.
🔹 Functional Divisions
- Somatic Nervous System: Controls voluntary actions (e.g. moving limbs).
- Autonomic Nervous System: Controls involuntary functions:
- Sympathetic: “Fight or flight”
- Parasympathetic: “Rest and digest”
🔹 Key Brain Regions
- Cerebrum: Conscious thought, memory, voluntary movement
- Cerebellum: Coordination and balance
- Medulla oblongata: Controls breathing, heart rate
- Hypothalamus: Regulates homeostasis (temperature, hunger)
- Corpus callosum: Connects left and right brain hemispheres
🔹 Reflexes
- Rapid, involuntary responses processed by the spinal cord (e.g. knee jerk).
