Chapter 4: Neural Conduction and Synaptic Transmission

Resting Membrane Potential

The electrical charge difference across a neuron's membrane when at rest, approximately -70mV.

Sodium-Potassium Pump

A mechanism that moves 3 Na⁺ ions out of the neuron and 2 K⁺ ions into the neuron.

All-or-none Principle

The principle that an action potential occurs only if the threshold of -55mV is reached.

Depolarization

The phase of action potential when Na⁺ channels open, causing Na⁺ to rush in and the membrane to become positive.

Repolarization

The phase of action potential when K⁺ channels open, allowing K⁺ to exit and restoring the membrane's negativity.

Saltatory conduction

A method of action potential propagation in myelinated axons where the signal jumps between Nodes of Ranvier.

Synapse

The junction between two neurons, consisting of a presynaptic neuron, synaptic cleft, and postsynaptic neuron.

Neurotransmitter

Chemical messengers that transmit signals across the synapse from one neuron to another.

Glutamate

The main excitatory neurotransmitter involved in cognitive functions.

GABA (Gamma-Aminobutyric Acid)

The main inhibitory neurotransmitter in the brain.

Reuptake

The process by which neurotransmitters are taken back into the presynaptic neurons after their release.

Antagonists

Substances that block receptors to inhibit neurotransmitter action.

Agonists

Substances that mimic neurotransmitters to enhance their effects.

Metabotropic Receptors

Receptor types that use G-proteins for slower and longer effects compared to ionotropic receptors.

Acetylcholine

A neurotransmitter involved in muscle control and learning.

Dopamine

A neurotransmitter associated with reward, motivation, and movement.

Endorphins

Neurotransmitters that act as natural pain relievers and are associated with feelings of pleasure.