Nervous systems
Keywords (reading p. 960-976)
Example of overlapping function
Neurons, the cells of the nervous system
PPT Slide
Structural diversity of neurons
Neurons conduct electrical signals
Membrane potential
What is the basis for the membrane potential?
Ionic composition of intracellular and extracellular fluid
Recall that the membrane can have channels that allow facilitated diffusion to occur
What will happen to K+? Na+?
Flow of K+ >> Na+ therefore net loss of positive charge from cell
Gradient between extracellular and intracellular fluid favors loss of K+ from the cell
This makes the inside of the cell more negatively charged than the outside
Two reasons:
Sodium-potassium ATPase
Excitable cells
Action potential
Hyperpolarization
depolarization
Action potentials occur because of voltage gated ion channels
Resting state
Initially only Na+ channels open
Voltage gated K+ channels also open
Undershoot
Tetrodotoxin
Propagation of the action potential
Propagation: what happens at the level of the ion channels
Depolarization at second segment results in the opening of voltage gated Na+ channels and a second action potential occurs
High performance axons
Nodes of Ranvier
How do neurons communicate with other cells?
Synapse between neurons
Electrical synapse
Chemical synapse
Chemical synapse: a closer look
What happens when neurotransmitter binds to ion channels on the post synaptic membrane?
How do the channels close again?
Email: rlee@mail.wsu.edu
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