The Nervous System

1. The Nervous System

2. The Nervous System

3. Central Nervous System (CNS) • The central nervous system is the control center of the body. It includes the brain and spinal cord.

4. Peripheral Nervous System (PNS) • The peripheral nervous system consists of a network of nerves that branch out from the central nervous system and connect it to the rest of the body. The peripheral nervous system is involved in both involuntary and voluntary actions.

5. Neurons

6. Neurons Sensory • __________ – carry messages from the sense organs to the brain and spinal cord (CNS) • __________ – carry messages from CNS to muscles and glands • __________ – located in CNS, connect sensory and motor neurons Motor Interneuron

7. Neurons Interneuron Sensory Motor

8. Neurons Cell Body Axon Dendrites Axon ends

9. ________ vs. _________ Axon Dendrite Carry messages into the cell body Have rough surfaces Many per cell Branch near cell body Carry messages away from cell body Have smooth surfaces Usually one per cell Branch away from cell body

10. Synapse For a nerve impulse to be carried along at a synapse, it must cross the gap between the axon and the next structure. The axon tips release chemicals called neurotransmitters that carry the impulse across the gap.

11. 3. _____________ – info is sorted and interpreted, response is determined Interpretation Reflex Arc - the pathway of a message 2. _____________ – sensory neurons transmit the stimulus message to the CNS Transmission 4. ______________ – motor neurons transmit a response message Transmission 1. ___________ – sense a stimulus Reception 5. ___________ – action taken in response to stimulus Response

12. Brain Functions Cerebrum – largest part of brain, controls voluntary muscles, thinking, learning, memory, and senses Cerebellum – coordinates muscle movement and balance Medulla – top of brainstem, controls automatic things like breathing, heart beat, and involuntary muscles (digestion)