1. THE NERVOUS SYSTEM II pp

2. FUNCTION
network of neurons that communicate and control the body through electrical impulses
Includes neurons, brain and spinal cord

4. Synapse Synapse: point where an axon and dendrite meet
Neurotransmitter – chemical that carries the message across the synapse

5. NERVE IMPULSES
Membrane potential- difference in charge inside and outside cell
Resting potential: inactive cell due to “negatively” charged inside as compared to outside

6. NERVE IMPULSES Action potential (electrical signals)
When dendrite is stimulated, NA+ channels along the axon open making inside positive

7. NERVE IMPULSES Action potential
When dendrite is stimulated, NA+ channels along the axon open making inside positive
As soon as they open, K+ channels pump K+ out restoring a negative resting potential.

8. NERVE IMPULSES
When the impulse reaches terminal neurotransmitters are released into synaptic cleft
This causes the next neuron to become more positive and the action potential continues or stimulates a muscle or gland

10. Effect of drugs on the nervous system

11. Drugs may…. Prevent re-uptake of neurotransmitters
Over stimulation of nervous system
Mimicking neurotransmitters

12. Two parts to Nervous System

13. CENTRAL NERVOUS SYSTEM (CNS)
Receives , interprets, processes, and creates messages
Parts
Brain – control center
Spinal cord –link between brain and Peripheral NS.

16. PERIPHERAL NERVOUS SYSTEM PNS
Carries impulses (messages) to and from the CNS.
Motor division
1. somatic nervous system (voluntary):
transmits impulses to and from skeletal
muscle

17. 2. Autonomic nervous system (involuntary) – controls glands, internal organs, and other smooth muscle tissue.