Nervous System Nervous System Structures Three main parts

Nervous System

Nervous System

Structures • Three main parts • Brain • Spinal Cord • Sensory Organs • Split into two categories • Central • Peripheral

Central Nervous System • In charge of interpreting information and sending instructions to the body • Two main parts: • Brain • Spinal Cord

Brain • Most complex organ of the body • Made of cells that DO NOT REGROW • Any damage to the brain is permanent • Has three major parts, cerebrum, cerebellum and brain stem

Cerebrum • Controls conscious functions (reasoning, language, sight, touch and hearing) • Divided into two similar hemispheres which are then divided into four additional lobes

Cerebellum/Brain Stem • Cerebellum • Coordinates body movements • Brain Stem • Connects the brain to the spinal cord • Controls unconscious functions

Spinal Cord • Thin bundle of nerve fibers • Extends from the brain stem to the pelvis • Carries signals to and from the brain and the peripheral nervous system

Peripheral Nervous System • The network of nerves that exist outside the central nervous system • Has two main jobs, sense and send • Sensory neurons send signals to the brain • Motor neurons send signals from the CNS to the muscles and glands

Parts of the PNS • Sight • Controlled by the eye • Detects light/color at the retina which sends a signal to the brain through the optic nerve to the brain (Occipital Lobe) • Hearing • Ability to sense sound waves • Sound waves (vibrations) travel to the eardrum making it vibrate • Those vibrations are then channeled to the liquid-filled cochlea which also vibrates • These vibrations cause tiny hair-cells to move which triggers a signal sent to the brain.

Eye Anatomy

Ear Anatomy

Signaling • Signals are sent along nerve cells or neurons • Neurons take chemical or physical signals and transmit them via electrical charges • These signals happen quickly • Damage to the neurons impairs the speed at which signals are sent • Too much damage and signals will cease to fire