1. Nervous System

2. Central Nervous System
CNS – The brain and spinal chord
Transmit information to the body

3. Peripheral Nervous System
Neurons that carry information in and out of the CNS

4. Neurons Neurons – nerve cells that transmit info.
Made of a cell body with a nucleus
Dendrite – receives signals
Axon – transmits signals
Synapse – where and axon meets a dendrite.
Glia – support cells, that nourish and insulate

6. Resting Potential Resting Potential – ion gradient of (+) outside
(-) inside
Sodium and Potassium are moved in and out of the cell by sodium potassium pumps and ion channels.
Sodium is pumped out potassium in, but potassium is allowed to flow back out, creating a positive charge on the outside and a negative charge on the inside of the membrane.**

8. Action Potential
Action Potential – a stimulus reverses the charge of the membrane.**
Gated ion channels open allowing sodium to flow in. This reverses the charge of the membrane.
In response, potassium channels open to let potassium out, thus restoring the charge.
Sodium potassium pumps restore the balance.

10. Conducting Action Potentials
The opening and closing of gated ion channels travels along the membrane of the axon
This causes a reversal of charge to travel down the membrane of the axon.
This is the electrical signal that nerves transmitt

11. **

12. Fast Conduction
Glia can wrap the axon in a layers of membrane insulation called a myelin sheath that acts like wire insulation
Schwann cells do this in the PNS,
oligodendrocytes do this in the CNS

13. Receiving action Potentials
Action potentials can be received electronically or chemically.
Electronically through another action potential like interaction
Chemically, through a synaptic vesicle releasing a neurotransmitter that flows through a synaptic cleft (synaptic signaling)**
Ex. Endorphins (decrease pain)

15. PNS organization Afferent neurons receive information
Efferent neurons cause actions to happen.

16. Efferent control
Efferent neurons control the motor system and the autonomic system.
Motor system consist of acts you can control. (walking)
Autonomic system consist of acts that are involuntary. (breathing)

18. Autonomic System
Sympathetic – causes processes to become enhanced (breath faster, pump more blood)
Parasympathtic – causes processes to relax
Enteric division – control digestive activities.