Week 3 (Depolarization, Neurotransmitter, Membrane Receptors, Sodium/Potassium Pumps)

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Depolarization

• When the polarization of the cell membrane is reduced towards 0

• For action potential to occur the cell must be depolarized

What a neurotransmitter

A neurotransmitter is a chemical in the brain that is stored at axon terminals than enable cell communication.

Classes of Neurotransmitter

Amino Acids

• Glutamate

• Gaba

• Glycine

• Aspartate

Monoamines

• Dopamine

• Norepinephrine'

• Epinephrine

• Serotonin

Modified Amino Acid

• Acetylcholine

Neuropeptides

• Endorphins

• Substance P

Purines

• ATP

• Adenosine

Gases

• Nitric oxide

Membrane Receptor Types

• Ligand(Chemical)-Gated

  • Opens when a certain neurotransmitter binds to it

• Mechanically-Gated

  • Opens when the membrane has pressure applied to it

• Always Open

  • Leak channels are always open to a certain ion

  • Leak K+ channels are always open and constantly pushing the membrane potential to near resting (always near equilibrium)

• Voltage(Electrical)-Gated

  • Open when the membrane voltage reaches a certain state

Sodium/Potassium Pump

• Trades 3 intracellular Na ions for 2 extracellular K+ ions

• Helps to create Na and K gradients

• Help keeps membrane potential negative

• Sodium goes out and potassium goes in

Leak channels and Na/K pumps keep the neurons at rest