Neurobiology Part 4: Synapses

Flashcards covering key terminology related to synapses, neurotransmitters, and neural integration from the Neurobiology Part 4 lecture notes.

Synapse

Junctions that mediate information transfer from one neuron to another neuron or to an effector cell.

Presynaptic neuron

The neuron conducting impulses toward the synapse, sending information.

Postsynaptic neuron

The neuron transmitting an electrical signal away from the synapse, receiving information.

Axodendritic synapse

A synaptic connection between the axon terminals of one neuron and the dendrite of another.

Axosomatic synapse

A synaptic connection between the axon terminals of one neuron and the soma (cell body) of another.

Axoaxonic synapse

A synaptic connection between an axon terminal of one neuron and the axon of another.

Electrical synapse

A type of synapse where the signal is mediated by gap junctions, allowing very rapid communication.

Chemical synapse

A type of synapse specialized for the release and reception of chemical neurotransmitters.

Gap junctions

Structures that connect the cytoplasm of adjacent neurons, enabling electrical coupling in electrical synapses.

Synaptic cleft

The fluid-filled space separating the axon terminal of the presynaptic neuron and the receptor region of the postsynaptic neuron.

Synaptic Transmission Termination

The process by which neurotransmitter effects are stopped, typically by reuptake, enzymatic degradation, or diffusion away from the synaptic cleft.

EPSP (Excitatory Postsynaptic Potential)

Graded potentials that cause depolarization in the postsynaptic neuron, making it more likely to fire an action potential.

IPSP (Inhibitory Postsynaptic Potential)

Graded potentials that cause hyperpolarization in the postsynaptic neuron, making it less likely to fire an action potential.

Graded potential

Small, local changes in membrane potential that occur in the receiving neuron's dendrites or cell body at synapses.

Neurotransmitters

Chemical messengers of the nervous system that mediate information transfer across synapses.

Acetylcholine (ACh)

The first identified neurotransmitter, released at neuromuscular junctions to cause muscle contraction, and used by PNS and some CNS neurons.

Dopamine (DA)

A neurotransmitter associated with pleasurable feelings, reward systems, movement regulation, and cognition; deficits are linked to Parkinson's disease and schizophrenia.

Norepinephrine (NE)

A neurotransmitter produced in the brain and PNS, active in the fight-or-flight response, alerting reactions, arousal, sleep regulation, mood, and blood pressure.

Epinephrine (Adrenaline)

A hormone/neurotransmitter released by the adrenal medulla during stress (fight or flight response), accelerating heart rate, constricting blood vessels, and dilating air passages.

Serotonin

A neurotransmitter involved in the regulation of mood, sleep, appetite, temperature, and sensory perception, found in the brain and gut.

Glutamate

An amino acid neurotransmitter that is usually excitatory.

Glycine

An amino acid neurotransmitter that is usually inhibitory.

GABA (gamma-aminobutyric acid)

An amino acid neurotransmitter that is usually inhibitory.

Substance P

A neuropeptide that acts as a mediator of pain signals.

Endorphins

Neuropeptides (like Beta endorphin, dynorphin, and enkephalins) that act as natural opiates, reducing pain perception.

Endocannabinoids

Lipid-soluble neurotransmitters synthesized on demand, involved in learning, memory, neuronal development, appetite control, and nausea suppression; act at the same receptors as THC.

Neural integration

The process where neurons function together in groups to contribute to broader neural functions, ensuring a smoothly operating whole system.

Synaptic plasticity

The brain's dynamic ability where synaptic activity leads to changes in synaptic strength, reflecting how experience shapes the brain (what fires together, wires together).

Channel-linked receptors

Neurotransmitter receptors that are also ion channels, causing rapid synaptic transmission when a ligand binds.

G protein–linked receptors

Neurotransmitter receptors that cause indirect, complex, slow, and often prolonged responses involving transmembrane protein complexes and widespread metabolic changes.