unit 2 notes: nervous system basics tuesday 2-23-2010
TRANSCRIPT
Unit 2 Notes:
Nervous System Basics
Tuesday
2-23-2010
(1) Function
• Respond to stimuli
• Process information
• Communicate
• Maintain homeostasis
• Basic Pathway:Sensory Input Integrate & Process Motor Output
(2) Structure
• Made of:– Brain– Spinal cord– Neurons– Junctions
• Has a complex organization (hierarchy) of sensory and motor levels.
(3) Brain & Spine
• Brain divided into lobes
• Spinal cord = communication highway
• All nerves communicate through Spine
• Example: Paralysis
(4) Neuron• Neuron = Nerve Cell
• Types: Multipolar + Unipolar
• Basic Structural Components:– Dendrites (Incoming)– Cell Body (Integrate + Process)– Axon (Outgoing)–Myelin Sheath (Insulation + Speed)– Axon Terminal (Final Destination)
(5) Unipolar Neurons
• Use: 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)
(6) Multipolar Neurons• Use: 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)
(7) Junctions
• Junction = Meeting of Neuron + Neuron or Neuron + Organ– A.K.A. Synapse, Synaptic Cleft
• Nerve Impulse Axon Axon Terminal Release Neurotransmitter– Neurotransmitter = Chemical Message– Causes an effect– Binds with cell membrane on other side
(8) 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)
PARASYMPATHETIC(REST & DIGEST)
SYMPATHETIC(FIGHT / FLIGHT)
(9) Sensory Input
• Afferent Input (away from body)
• Sends message from body part Brain
• Initial stimulus or Imbalance
(10) Central Nervous System (CNS)
• INCLUDES: Brain & Spinal cord
• “Head Honcho”– Notified of everything, Makes all decisions
(11) 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
(12) Motor / Efferent Output
• CNS Effector Organ– CNS makes decision– CNS sends message to release chemical, or
move– GOAL:GOAL: Regain Balance / Do What You Want
• 2 Divisions:– Autonomic Nervous System– Somatic Nervous System
(13) Somatic Nervous System
• Voluntary Actions
• Skeletal Muscle
• (All other actions are
involuntary)
(14) Autonomic Nervous System
• Involuntary Actions– Autonomic : Autopilot– Processes occur naturally without thought
• 2 Subdivisions:– Parasympathetic
Pathway– Sympathetic
Pathway
(15) Parasympathetic Pathway
• (Involuntary)
• “Rest & Digest”
• Normal bodily functions:– Digestion , Excretion– Lens Contraction, Blinking– Gas Exchange– Sleep
(16) Sympathetic Pathway
• (Involuntary)
• “Fight or Flight”
• Bodily Functions during heightened excitement:– Increased heart rate, respiration– Increased sweating– Increased blood flow