Neurophysiology 2

What are the Two main nervous tissue cell types

Neurons and neuroglia.

Structural neuron types

Pseudounipolar, bipolar, multipolar.

Most common neuron type

Multipolar neuron.

Interneuron function

Connects neurons within CNS.

Axonal transport purpose

Moves materials along axon.

Anterograde transport

Kinesin-mediated movement from soma outward.

Retrograde transport

Dynein-mediated movement toward soma.

Clinical relevance of retrograde transport

Pathway for viral infection of CNS.

Myelin in PNS

Produced by Schwann cells.

Myelin in CNS

Produced by oligodendrocytes.

White matter

Myelinated axons.

Gray matter

Cell bodies and dendrites.

Blood-brain barrier function

Protects brain from harmful substances.

BBB structure

Tight junctions between endothelial cells.

Astrocyte role in BBB

Regulates permeability and ion balance.

Depolarization

Membrane potential becomes less negative.

Repolarization

Return to resting potential.

Hyperpolarization

Membrane becomes more negative than resting.

Absolute refractory period

No second action potential possible.

Relative refractory period

Stronger stimulus required.

Electrical synapse locations

Cardiac muscle, smooth muscle, some neurons.

Chemical synapse advantage

Signal amplification and modulation.

Role of calcium in synapse

Triggers neurotransmitter release.

Ligand-gated ion channels

Open directly when neurotransmitter binds, found in the dendrites

G-protein coupled receptors

Indirectly open channels via second messengers.

Second messenger example

cAMP.

Effect of GPCR signaling

Slower but longer-lasting effects.

Acetylcholine function

Excitatory or inhibitory depending on receptor.

Nicotinic ACh receptors

Ligand-gated Na+ ion channels.

Muscarinic ACh receptors

G-protein coupled receptors.

Acetylcholinesterase function

Breaks down acetylcholine.

Monoamines definition

Neurotransmitters derived from amino acids.

Examples of monoamines

Dopamine, norepinephrine, serotonin.

Monoamine inactivation

Reuptake and MAO degradation.

SSRIs mechanism

Block serotonin reuptake.

Glutamate role

Major excitatory neurotransmitter.

GABA role

Major inhibitory neurotransmitter.

Glycine function

Inhibitory neurotransmitter in spinal cord.

Neuropeptides function

Modulate pain, hunger, satiety.

Nitric oxide signaling

Diffuses freely, activates cGMP.

Endocannabinoids function

Suppress inhibition and modulate learning.

Voltage gated ion channel

Transmembrane proteins that open and close in response to changes in membrane potential, regulating the flow of ions. Found in the axon.

Agonist

Drugs that stimulate a receptor (Excitation)

Antagonist

Drugs that inhibit a receptor (Deactivate)

EPSPs (Excitatory Postsynaptic Potentials)

electrical signals in neurons that depolarize (EPSP, closer to firing) the postsynaptic membrane

IPSPs (Inhibitory Postsynaptic Potentials)

Electrical signals in neurons that hyperpolarize (IPSP, further from firing) the postsynaptic membrane