Neurons

Water attaches, to it

ex. Phosphate head of phospholipid bilayer

repelled by water

ex. Lipid tails of phospholipid bilayer

• K+ , protein- (amino acids)
•   --not equal concentration

• branched like extentions
• 

Na+ (very positive) + mvolt

• Bring Positive ions in neuron.
• A change in the RMP
• Occurs on the dendrites or cell body
• + ions are depolarizing(+ions come across

a separation of change across a membrane

RMP becomes more (-)

+ ions come across membrane

Becomes more positive

Amount of depolarization required to generate an impulse (Current flowing down an axon).

by channel proteins

1. Leak Channel

2. Chemically Gated Channel

3. Voltage Gated Channel

4. Mechanically Gated Channel

Leak ions back and forth A.M.

...out of cell

.....in the cell at slower rate

A chemical bonds to membrane to open an ion channel.

• Pumps
• 3 Na+ out &
• 2 K+ in

• Respond to a change in the trasmembrane ptential ( RMP)
• When RMP -70mV reach treshold (-55mV) Na+ gates open axon action potential