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

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. Autonomic Nervous System 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