The Human Nervous SystemBody wide system of nerve cells that collects information from the world, processes this information and then takes action by directing body organs and muscles via the transmission of electro chemical messages.

Central Nervous system (CNS)Complex processing.

Peripheral Nervous system (PNS)Body wide network of messenger neurones.Sensory (Afferent) neurons to CNS, and motor (Efferent) neurons away from CNS

BrainAll conscious and most unconscious processing

Spinal cordReceives and transmits information. Some reflex processing

Autonomic Nervous system (ANS)<ul><li>Controls actions of internal organs and glands.</li><li>Involuntary system (not under conscious control)</li></ul>

Somatic Nervous system (SNS)<ul><li>Controls skeletal muscles (for movement)</li><li>Voluntary system (under conscious control)</li></ul>

SympatheticIncreases Bodily activities.Release of noradrenalineActivates in stress response (Fight or Flight)<ul><li>Heart rate increase</li><li>Sweat increase</li><li>Breathing rate increase</li><li>Dilates pupils</li><li>Inhibits digestion</li></ul>

ParasympatheticDecreases bodily activities.Release of noradrenalineActivates in rest (Rest and Digest)<ul><li>Heart rate decrease</li><li>Sweat decrease</li><li>Breathing rate decrease</li><li>Constricts pupils</li><li>Stimulates digestion</li></ul>

Homeostasis - regulation of the internal environment<ul><li>In normal conditions there is a balance between sympathetic and parasympathetic systems. This is called maintaining homeostasis</li></ul>

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