Transcript The Nervous System - Downtown Magnets High School

Communication and
The Nervous System
Big Idea 3: Living systems store,
retrieve, transmit, and respond to
info essential to life processes.
Essential Knowledge
• 3E1: Individuals can act on info and
communicate it to others
• 3E2:Animals have nervous systems that
can detect external and internal signals,
transmit and integrate info, and produce
responses.
Orgs Exchange Info
• Respond to cue and change behavior.
• Ex: Protection of Young (Encircling)
Communication:
Signal Cues
• Produce
changes in
behavior that
affect
reproductive
success.
• Ex: Terretorial
Markings in
Mammals
Animals use Cues
to Indicate
dominance..
Bird Songs
Natural Selection Favors Innate/Learned
Behaviors that Increase Survival and
Reproductive Fitness.
Mating of Fruit Flies
Cooperative Behavior
• Increases fitness and survival of population!
Animal Nervous Systems
• Used to detect external and internal
signals, transmit and integrate info, and
produce responses.
Neuron: Basic Cell of NS!
Dendrites: Receive
Info
Axon Terminal
Node of Ranvier
Cell Body: Fxnal
Cell
Nucleus
Myelin
Schwann Cell
Detection
Integration
Transmission
Messages are electrical signals
called impulses.
Impulse Speed
• Increases with myelin (80% lipid, 20% protein)
• Myelin surrounds axon; acts as electric insulator
• Created from Schwann cells.
Dr. Connection: Multiple Sclerosis
• Inflammatory disease in which myelin
around axons of nervous system is
damaged  leads
to demyelination and scarring.
Types of Neurons
1) sensory: carry impulses from sense
organs to brain and spinal cord.
2) motor: carry impulse from brain and
spinal cord to muscles.
3) Interneurons: connect sensory and motor
Sensory
Interneuron
Motor
Start the Message!
• Neurons must reach a threshold 
stimulus that is required to activate a
neuron.
Nerve Impulse Review
1) Impulses move down neuron b/c of movement
of ions across cell membrane.
2) At Resting potential: -70 mV, Active transport
(ATP req’rd): Na+ out  K+ in.
3) Depolarization: Disturbance opens Na
channels, lets lots of Na in. Chain reaction of
Na opening  Action potential.
4) Repolarization: Restoring back to normal.
Passing of Impulse
• Signal reaches axon terminal.
• Tiny sacs filled w/ neurotransmitters are
released into synapse  transmits info to
neighboring dendrites.
Common Neurotransmitters
• All are chemical messengers that pass
impulses across synapses to the next neuron.
• Examples: Acetylcholine, Epinephrine,
Norepinephrine, Dopamine, Serotonin, GABA
Neurotransmitters
• Cause a response (muscle contraction,
futher nerve response)
• Can be stimulatory or inhibitory
Parts of the
Vertebrate Brain
Nervous System
Neurotransmitters Research