Cell Structures, Ion channels, Resting membran potential, Graded potentials, action potential, refractory periods, propagation, neuroglia (cns), neuroglia (pns), neuron classification, synapses, chemical synapse steps, EPSP vs IPSP, Summation, neurotransmitters, neuromodulators, neural circuits, repair

What are Nissl bodies?

Rough ER —> protein synthesis

What are neurofilaments?

Structural support

What is axoplasm?

Cytoplasm of axon

What are telodendria?

Axon terminal branches

Types of ion channels?

Passive, chemically-gated, mechanically-gated, voltage-gated

Which channels create action potentials?

Voltage-gated channels

Which respond to neurotransmitters?

Chemically (ligand)-gated

What is resting membrane potential?

~70 mV

Why is inside of cell negative

• Na⁺ pumped out

• K leaks out

• Negative proteins inside

What does Na/K pump do?

3 Na out, 2 K in

What is a graded potential?

Local change in membrane potential

Depolarization vs hyperpolization?

Depolarization = more positive

Hyperpolarization = more negative

Where do graded potentials occur?

Dendrites & soma

What triggers an action potential?

Threshold (~ -55 to - 60mV)

What is the all-or-none principle?

Either threshold is reached and the AP happens, or nothing happens at all

Steps of Action potential?

1. Depolarization (Na in)

2. Repolarization (K out)

3. Hyperpolarization

Peak membrane potential?

~ +30 mV

Absolute refractory period?

No new AP possible

Relative refractory period?

Strong stimulus required

Continuous conduction vs Saltatory conduction

C: Step-by-step (unmyelinated)
S: Jumps node to node (myelinated)

Why is myelin important?

Speeds conduction

Astrocytes function?

Blood-brain barrier, support, repair

Oligodendrocytes function?

Form myelin in CNS

Microglia function?

Phagocytosis (destory foreign particles, bacteria, or dead cell debris)

Ependymal calls?

Produce Cerebrospinal Fluid

Schwann cells?

Myelin in PNS

Satellite cells?

Support neuron cell bodies

Structural types of neurons?

Multipolar, bipolar, unipolar

Most common neuron?

Multipolar

Functional types?

Sensory, motor, interneurons

What is a synapse?

Communication point between cells

Electrical vs chemical synapse?

Electrical = direct, fast
Chemical = Neurotransmitter-based

Steps of neurotransmitter release?

1. AP arrives

2. Ca enters

3. Vesicles release NT

4. NT binds receptors

5. Ion channels open

Excitatory Postsynaptic Potentials?

Depolarization (Na in)

Inhibitory Postsynaptic Potentials

Hyperpolarization (K out, or Cl in)

Spatial summation?

Multiple neurons

Temporal summation?

Rapid firing of one neuron

Acetylcholine (ACh)

Most common; NMJ (Neuromuscular junction)

Norepinephrine?

Sympathetic, excitatory

Dopamine?

Movement control

Serotonin?

Mood regulation

Glutamate

Excitaory

GABA?

Inhibitory

What are neuromodulators?

Modify synpatic activity

Example of neuromodulator

Endorphins (pain control)

Diverging circuit?

One —> many

Converging circuit?

Many —> One

Reverberating circuit?

Feedback loop

Parallel after-discharge?

Same signal arrives at different times

Can CNS neurons repair?

Very limited

Can PNS neurons repair?

Yes, witch Schwann cells

What is Wallerian degeneration?

Breakdown distal to injury