Nervous System
Purpose of the Nervous System 1. Allows for communication between the brain, senses, nerves, and the environment (Uses Electrical impulses-Nerve Impulses) 2. Allows us to react to changes (Stimuli) 3. Protects us from harm
Parts of the Nervous System Brain Brain Brain stem Spinal cord Neurons (nerves) Brain Stem Spinal Cord Neurons
Neuron Structure Cell Body- Similar to any other body cells, contains organelles Dendrites- Finger-like structures that take in messages from other neurons and environment Axon- Arm-like structures that carry messages away from the cell body
Synapse- the space between neurons that signals travel across Axon Terminal –send signals from one neuron across a synapse to another neuron Synapse- the space between neurons that signals travel across Dendrites Axon Cell Body Axon Terminal Synapse
Types of Neurons 1. Sensory Neurons- nerve cells that “send signals about stimuli from senses TO the spinal cord and brain” 2. Motor Neurons- nerve cells that “send messages for movement to muscles FROM the spinal cord and brain”
Communication Neurotransmitters- chemicals found in synapses that allow for electrical impulses to pass from one nerve to the next Nerve Impulses- Electrical charges that travel through nerve cells carrying a message Reaction Time- Amount of time from stimulus to response
Senses Touch – sensory receptors in the skin Taste – chemoreceptors on your tongue detect chemicals in food Smell – chemoreceptors in your nose detect odor Hearing – auditory receptors detect sound waves Sight – rods and cones in the eyes detect light
Brain Main Parts Cerebrum- Main part of the brain found in the front; controls memory, thinking, learning, speech, senses Cerebellum- Back part of the brain that controls voluntary muscle functions, coordination, and balance Medulla- “Brain Stem” that connects the brain to the spinal cord, found in bottom back section of the brain, controls involuntary muscle functions
Cerebrum Cerebellum Brain Stem (Medulla)
Brain Function Develops through experiences and stimuli Creates new connections between neurons to find the fastest pathway for response Receives messages about the environment and decides on responses (Long and Short Term memory)