The Nervous System

1. The Nervous System Your Friend

2. The Nervous System • Regulates our internal functions • Involved in how we react to the external environment • Two main parts • Central Nervous System • Peripheral Nervous System

4. Neurons • Nerve cells that run through our entire body and communicate with each other • Receive messages from parts of the body (muscles, glands, etc) • 100 Billion in our bodies, mostly in the brain

5. Neurons are composed of: • Cell body (soma): directs actions of the cell • Dendrites: extensions that receive information • Axon: extends from cell body, carries electrical potential, sends a chemical message to adjacent neurons via terminal buttons

6. Messages are sent from the axon terminals of one neuron to the dendrites of another Neurons are for Communicating

7. Synapse • In order for the message to send from neuron to neuron they must cross the synapse • The message only goes in one direction Dendrites > Cell Body > Axon > Axon Terminals > Dendrites…..

8. Synapse

9. Neurotransmitters • Neurons send messages across the synapse through the release of neurotransmitters • Chemicals stored in sacs in the axon terminals • Several types, each with a specific structure and can only fit into a specific receptor site

10. Types of Neurotransmitters • Serotonin – affects mood, sleep, sensory perception, and other functions, may play a role in psychological disorders like depression • Acetylcholine – involved in memory, muscle action, sleep, emotions, those w/ Alzheimer’s have lower levels • Dopamine – affects movement, attention, memory, learning, plays role in addiction • Norepinephrine – affects learning, memory, emotions, eating, alertness, etc. • Epinephrine – emotions, memory storage…

12. Central Nervous System • Made up of: • Brain (we will talk about this later) • Spinal Cord • Extends from the brain down the back • Column of nerves, as thick as your thumb • Spinal Reflexes • When your knee kicks at the doctors office • Blinking when you get something in our eye

14. Peripheral Nervous System • Responsible for transmitting messages between the CNS and the rest of the body • Two Main Systems in the PNS: • Somatic Nervous System • Autonomic Nervous System

15. Somatic Nervous System • Transmits messages to the CNS • Activated by touch, pain, changes in temperature or changes in body positions • Sends messages to muscles and glands

16. Autonomic Nervous System • Regulates the body’s vital functions • Heartbeat, breathing, digestion, etc. • Two divisions: • Parasympathetic • Sympathetic

17. Parasympathetic Restores bodies energy after an action has occurred Slows down heartbeat, digestion, breathing Sympathetic Fight or flight response Activated when the body is put in a stressful situation Autonomic Nervous System