1. Unit 2: Nervous System
Monday

2. Basic Function Purpose: Respond to stimuli Process information
Communicate
Maintain homeostasis
Sensory Input  Integrate & Process  Motor Output

3. Basic Structure Made of: Has a complex organization (hierarchy) Brain
Spinal cord
Neurons
Junctions
Has a complex organization (hierarchy)

4. Brain & Spine Brain divided into lobes
Spinal cord = communication highway
All nerves communicate through Spine
Example: Paralysis

5. Neuron Neuron = Nerve Cell Types: Multipolar + Unipolar
Basic Structural Components:
Dendrites (Incoming)
Cell Body (Integrate + Process)
Axon (Outgoing)
Myelin Sheath (Insulation)
Axon Terminal (Final Destination)

8. Unipolar Neurons Afferent Input (Sensory Input)
Dendrites connected to sensory organ
Message sent to cell body  Out Axon
Message sent out of axon terminal
FOCUS:
Get message to CNS
Let CNS process and decide
(NO need to have cell body right by dendrites)

10. Multipolar Neurons Efferent Output (Motor Output)
Multi = Lots of extensions coming from cell body
Cell body directly connected to dendrites
Dendrites coming from CNS / Efferent path  effected organ
FOCUS:
Organize messages by importance
Make organs do things
(Important to have cell body right next to dendrites)

13. Junctions Junction = Meeting of Neuron + Neuron or Neuron + Organ
Neurons don’t actually touch anything  Synaptic Cleft
Nerve Impulse  Axon  Axon Terminal  Release Neurotransmitter
Neurotransmitter = Chemical Message
Causes an effect
Binds with cell membrane on other side

16. Nervous System Organization
CENTRAL NERVOUS SYSTEM
PERIPHERAL NERVOUS SYSTEM
(SENSORY / AFFERENT INPUT)
PERIPHERAL NERVOUS SYSTEM
(MOTOR / EFFERENT OUTPUT)
BODY
(INITIAL STIMULUS
/ IMBALANCE)
AUTONOMIC
(INVOLUNTARY)
SOMATIC
(VOLUNTARY)
SYMPATHETIC
(FIGHT / FLIGHT)
PARASYMPATHETIC
(REST & DIGEST)

17. Sensory Input Afferent Input (away from body)
Sends message from body part  Brain
Initial stimulus or Imbalance

18. Central Nervous System (CNS)
INCLUDES: Brain & Spinal cord
“Head Honcho”
Notified of everything, Makes all decisions

19. Peripheral Nervous System (PNS)
“Middle Man” / Body Guard: Body—CNS
Helps organize messages being sent to CNS and to organs.
2 Divisions:
Sensory/Afferent Input
Motor/Efferent Output

20. Motor / Efferent Output
CNS  Effector Organ
CNS makes decision
CNS sends message to release chemical, or move
GOAL: Regain Balance / Do What You Want
2 Divisions:
Autonomic Nervous System
Somatic Nervous System

22. Somatic Nervous System
Voluntary Actions
Skeletal Muscle
(All other actions are
involuntary)

23. Autonomic Nervous System
Involuntary Actions
Autonomic : Autopilot
Processes occur naturally without thought
2 Subdivisions:
Parasympathetic
Pathway
Sympathetic

24. Parasympathetic Pathway
(Involuntary)
“Rest & Digest”
Normal bodily functions:
Digestion , Excretion
Lens Contraction, Blinking
Gas Exchange
Sleep

25. Sympathetic Pathway (Involuntary) “Fight or Flight”
Bodily Functions during heightened excitement:
Increased heart rate, respiration
Increased sweating
Increased blood flow