뒤로Ch.11 Part 3
이 집합의 용어 (28)
A synapse is a junction that mediates information transfer from one neuron to another neuron or to an effector cell.
Presynaptic neuron conducts impulses toward the synapse (sends information). Postsynaptic neuron transmits electrical signals away from the synapse (receives information).
Axodendritic, axosomatic, axoaxonal, dendrodendritic, and somatodendritic synapses.
Chemical synapses and electrical synapses.
Composed of an axon terminal of the presynaptic neuron with synaptic vesicles and a receptor region on the postsynaptic membrane separated by a synaptic cleft.
By release, diffusion, and receptor binding of neurotransmitters across the synaptic cleft, ensuring unidirectional communication.
- AP arrives at presynaptic terminal
- Ca2+ channels open, Ca2+ enters
- Ca2+ triggers neurotransmitter release
- Neurotransmitter diffuses and binds receptors
- Ion channels open, creating graded potentials
- Neurotransmitter effect terminated
Time needed for neurotransmitter release, diffusion, and receptor binding, typically 0.3 to 5 milliseconds.
Neurons are electrically coupled by gap junctions allowing rapid, bidirectional or unidirectional communication.
EPSPs are excitatory postsynaptic potentials causing depolarization; IPSPs are inhibitory postsynaptic potentials causing hyperpolarization.
EPSPs depolarize the postsynaptic membrane; if threshold is reached at the axon hillock, voltage-gated channels open to trigger an AP.
IPSPs increase membrane permeability to K+ or Cl−, hyperpolarizing the membrane and moving it farther from threshold.
Multiple EPSPs from one or more presynaptic neurons occur in rapid succession, adding together to influence the postsynaptic neuron.
EPSPs from multiple presynaptic neurons at different locations add together to influence the postsynaptic neuron.
Repeated use of a synapse increases presynaptic Ca2+ levels, enhancing neurotransmitter release and postsynaptic response, important for learning and memory.
One neuron inhibits neurotransmitter release from another neuron via an axoaxonal synapse, reducing EPSPs.
Graded potentials travel short distances (0.1–1.0 mm), while action potentials travel long distances along the axon.
The type of receptor it binds to determines if the effect is excitatory (depolarizing) or inhibitory (hyperpolarizing).
Direct action opens ion channels rapidly; indirect action uses G protein pathways causing slower, longer-lasting effects.
A chemical messenger that modulates synaptic strength without directly causing EPSPs or IPSPs, often affecting neurotransmitter synthesis or receptor sensitivity.
Ligand-gated ion channels that mediate rapid, brief synaptic transmission by allowing ion flow upon neurotransmitter binding.
Neurotransmitter binding activates G proteins, which produce second messengers like cAMP to modulate ion channels and cellular responses.
Neurons functioning in groups (neuronal pools) to integrate incoming information and forward processed signals to other destinations.
A single presynaptic fiber branches to synapse with multiple neurons; includes a discharge zone (high excitation) and a facilitated zone (lower excitation).
Information travels along one pathway sequentially, producing a specific, all-or-none response, such as a spinal reflex.
Receptor, sensory neuron, CNS integration center, motor neuron, and effector.
Input travels along multiple pathways simultaneously, allowing different parts of the brain to process information and produce multiple responses.
Diverging, converging, reverberating, and parallel after-discharge circuits.