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 dominan

ce..

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

Cell Body: Fxnal Cell

MyelinSchwann

Cell

Node of Ranvier

Axon Terminal

Nucleus

Messages are electrical signals called impulses.

Detection

Transmission

Integration

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.

http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter14/animation__the_nerve_impulse.html

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

Parts of the Vertebrate Brain

Nervous System Neurotransmitters Research