Electrical Signals 2

BIOL 1407

Propagation of AP in

Unmyelinated Axon

Saltatory Conduction

Chemical Synapses

• Junction between two neurons

• Chemical communication

• Neurotransmitters

Receptors

Norepinephrine Norepinephrine

Postsynaptic Potentials

• Changes in membrane potential of the postsynaptic membrane

• Receptors are chemically-gated channels

• Graded potential

EPSPs

• EPSP = Excitatory PostSynaptic Potential

• Depolarization• Receptors are usually

Na+ or Ca2+ channels

IPSPs

• IPSP = Inhibitory PostSynaptic Potential

• Hyperpolarization• Receptors are usually

K+ or Cl- channels

Summation

Comparative Nervous Systems

Vertebrate Nervous System

Brain Stem

Diencephalon

Photo Credit: University of Wisconsin and Michigan State Comparative Mammalian Brain Collections and the National Museum of Health and Medicine, Wikimedia Commons

Bird Brains

• Bird brains are complex on inside, not on surface

• PBS: Bird Brains• http://www.pbs.org/wgbh/

nova/sciencenow/3214/03-brain.html

• Video: http://www.youtube.com/watch?v=BGPGknpq3e0

Pigeon BrainPicture Credit: Biodidac

The End

Unless otherwise specified, all images in this presentation came from:

Campbell, et al. 2008. Biology, 8th ed. Pearson Benjamin Cummings.