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.
Communication: Signal Cues • Produce changes in
behavior that affect
reproductive success.
• Ex: Terretorial Markings in Mammals
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
Cell Body: Fxnal Cell
MyelinSchwann
Cell
Node of Ranvier
Axon Terminal
Nucleus
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
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.
Nerve Impulse Review
• Signal reaches axon terminal.
• Tiny sacs filled w/ neurotransmitters are released into synapse transmits info to
neighboring dendrites.
Passing of Impulse
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