1. Nervous System
Chapter 48

2. All Life: Responds to the Environment
Animals have evolved a complex nervous system which:
Detects external and internal signals
Transmit and integrate information
Produce responses

3. Primary Organ: Brain Different regions have different functions Vision
Hearing
Muscle movement
Abstract thought and emotion
Neuro-hormone production

4. Primary Cell: Neuron Structure: Function: Cell body Axon Dendrite
Detection
Generation
Transmission
Integration

5. Schwann cells Myelin sheath is electrical insulator
Impulses travel faster

6. How does a neuron transmit information
Resting Neuron:
Uses ATP to continually pump (3) NA+ out for every (2) K+ into the axon
This establishes an electrochemical gradient (resting membrane potential)

7. Neuron Animation

8. How does a neuron transmit information
Detection:
Sensory receptor cells convert a stimulus into a voltage

9. How does a neuron transmit information
Generation:
If the sensory cell converts enough stimuli into electricity, a threshold voltage is established and a signal is sent to open ion channels at the start of an axon

10. How does a neuron transmit information
Transmission:
Na+ and K+ gated channels sequentially open/close which cause local depolarization

11. How does a neuron transmit information
Transmission:
When the message reaches the end of the axon, it must cross a synapse
This process involves neurotransmitters (cell communication)
Acetylcholine
Epinephrine
Norepinephrine
Dopamine
Serotonin
GABA

12. How does a neuron transmit information
Integration:
Interneurons receive information and determine appropriate response

13. How does a neuron transmit information
Response:
Stimulatory or inhibitory output