Lecture Video Notes: Neural Communication and History (Action Potentials, Synapses, Cells, and History)

A set of Q&A flashcards covering action potentials, synaptic transmission, receptors, PSPs, neural integration, glial cells, neuron types, brain structure, and key historical concepts.

At the threshold of excitation, which channels open to initiate the action potential?

Voltage-gated sodium (Na+) channels open, allowing Na+ to enter the cell.

What follows the initial Na+ influx in the action potential sequence?

Voltage-gated potassium (K+) channels open and K+ exits the cell.

What triggers neurotransmitter release at the axon terminal?

The arrival of the action potential opens voltage-gated Ca2+ channels; Ca2+ enters and triggers vesicle fusion with the presynaptic membrane.

What happens during exocytosis at the synapse?

Synaptic vesicles fuse with the presynaptic membrane and release neurotransmitters into the synaptic cleft.

How do neurotransmitters influence the postsynaptic membrane?

They diffuse across the synapse and bind to receptors on the postsynaptic membrane, causing receptor-mediated effects.

What does the all-or-none law mean for an action potential?

The action potential either occurs fully or not at all, and it propagates with a constant amplitude and velocity.

What is saltatory conduction and where does it occur?

Conduction that jumps between the nodes of Ranvier in myelinated axons, speeding transmission.

What is the role of the node of Ranvier?

A gap in the myelin sheath where the action potential is regenerated, enabling saltatory conduction.

Name the two main receptor types for neurotransmitters and their basic differences.

Ionotropic receptors (directly open ion channels) and Metabotropic receptors (activate second messenger systems to influence ion channels).

What are AMPA and NMDA receptors in the glutamate system?

Both are ionotropic glutamate receptors; AMPA mediates fast Na+ influx, NMDA allows Na+ and Ca2+ influx and is voltage-dependent due to Mg2+ block, important for memory and learning.

What is an EPSP and what is an IPSP?

EPSP (excitatory postsynaptic potential) depolarizes the postsynaptic neuron; IPSP (inhibitory postsynaptic potential) hyperpolarizes it.

How are postsynaptic potentials terminated?

Primarily by reuptake of neurotransmitter into the presynaptic terminal and by enzymatic degradation.

Name two primary amino acid neurotransmitters and their general roles.

Glutamate – excitatory; GABA – inhibitory (glycine is inhibitory in the spinal cord).

What is the difference between GABAA and GABAB receptors?

GABAA is ionotropic (chloride channel); GABAB is metabotropic (G-protein coupled).

What is the role of glycine in the nervous system?

Glycine is an inhibitory neurotransmitter in the spinal cord, typically acting via chloride channels.

Which receptor type in the cortex is most associated with memory and learning and is activated by glutamate?

NMDA receptors, which allow Na+ and Ca2+ influx and require depolarization to relieve Mg2+ block.

What are astrocytes’ primary energy-related functions?

They take up glucose from capillaries, may convert it to lactate for neurons, and store glycogen for energy during high demand.

What do oligodendrocytes do and where are they located?

Oligodendrocytes form myelin sheaths around axons in the CNS, insulating and speeding transmission (myelinating multiple axons).

What do Schwann cells do and where are they located?

Schwann cells form myelin in the PNS around a single axon, guide axonal regrowth after damage.

What are the Nodes of Ranvier and why are they important?

Gaps in the myelin sheath where voltage-gated channels are concentrated, enabling saltatory conduction.

What are microglia?

Glial cells that remove debris and participate in inflammatory responses.

What are the major internal structures of a multipolar neuron, and their roles?

Nucleus (contains DNA), mitochondria (ATP production), endoplasmic reticulum (protein/ion storage), Golgi apparatus (lipid synthesis and packaging).

What are transcription and translation in neurons?

Transcription: genes → mRNA in the nucleus; Translation: mRNA → protein at ribosomes in the cytoplasm.

Which brain area is associated with speech production and who identified it?

Broca’s area; identified by Paul Broca.

What is the Doctrine of Specific Nerve Energies?

Nerve activity is perceived depending on the brain region; different nerves produce different perceptions based on brain processing (Müller & Flourens).

What do Descartes’ Dualism and Monoism propose?

Dualism: mind and body are separate; Monoism: everything is matter/energy and the mind arises from the nervous system.

Who are considered the Fathers of Modern Neuroscience and what is their contribution?

Camillo Golgi and Santiago Ramón y Cajal; foundational neuron anatomy studies and the development of modern neuroscience.

What is the resting membrane potential and its typical value?

Approximately -70 millivolts (mV) inside the neuron at rest.

What is the Na+/K+ pump’s stoichiometry and its energy cost?

3 Na+ are pumped out and 2 K+ are pumped in; uses ATP and accounts for a large portion of cellular energy.