This preview shows page 1. Sign up to view the full content.
Unformatted text preview: e a series
of action potentials
propagated in sequence
down the neuron.
• Only the axons of neurons
conduct the nerve impulse.
• Initiated at the hillock,
• Propagate toward the axon terminus Heyer 4 Coordination of Body Functions How can conduction rate be increased?
How can conduction
rate be increased? 2. Myelinated axons
— vertebrates only! 1. Increase diameter of the axon.
• Increase diffusion rate of cations
down through the axon.
• “Giant axons ” of cephalopod
molluscs and crustacean
arthropods may be 1mm in
diameter and have a conduction
speed of 100m/sec. Transmission:
Synapses & Local Signaling
• Synaptic terminals release a neurotransmitter.
– e.g. acetylcholine • NT binds to receptors on postsynaptic cell. Glands: organs specialized for secretion
Formation o f E pithelial G lands • Saltatory conduction : 25 µm myelinated vertebrate neuron
may have conduction rate of 120 m/sec. Transmission of the signals:
• Synapse: functional connection between a
View Full Document
This note was uploaded on 09/02/2011 for the course BIOL 6a taught by Professor Staff during the Fall '10 term at DeAnza College.
- Fall '10