Synapse
Junctions that mediate information transfer from one neuron to another neuron, or from one neuron to an effector cell.
Presynaptic Neuron
Neuron conducting impulses toward the synapse; it sends information.
1/44
Flashcards about the nervous system and nervous tissue.
Name | Mastery | Learn | Test | Matching | Spaced |
---|
No study sessions yet.
Synapse
Junctions that mediate information transfer from one neuron to another neuron, or from one neuron to an effector cell.
Presynaptic Neuron
Neuron conducting impulses toward the synapse; it sends information.
Postsynaptic Neuron
Neuron transmitting electrical signal away from the synapse; it receives information. In the PNS, this may be a neuron, muscle cell, or gland cell.
Axodendritic Synapse
Synapse between the axon terminals of one neuron and the dendrites of another.
Axosomatic Synapse
Synapse between the axon terminals of one neuron and the soma (cell body) of another.
Axoaxonal Synapse
Synapse from axon to axon
Dendrodendritic Synapse
Synapse from dendrite to dendrite
Somatodendritic Synapse
Synapse from soma to dendrite
Chemical Synapse
Specialized for the release and reception of chemical neurotransmitters.
Electrical Synapse
Neurons are electrically coupled; joined by gap junctions that connect the cytoplasm of adjacent neurons. Communication is very rapid and may be unidirectional or bidirectional.
Synaptic Cleft
Fluid-filled space separating the presynaptic and postsynaptic neurons.
Neurotransmitter
Chemical released at the synapse to transmit signals from one neuron to another.
Synaptic Vesicles
Small membrane-bound sacs in the axon terminal that contain neurotransmitters.
Voltage-gated Ca2+ channels
Channels that open when the action potential arrives at the axon terminal, allowing calcium ions to enter the axon terminal.
Synaptic Delay
Time needed for neurotransmitter to be released, diffuse across synapse, and bind to receptors. This is the rate-limiting step of neural transmission.
Gap Junctions
Connections that join neurons in electrical synapses.
Postsynaptic Potential
Graded potentials caused by neurotransmitter receptors that vary in strength.
EPSP
Excitatory postsynaptic potential; a local net graded potential depolarization.
IPSP
Inhibitory postsynaptic potential; binding to receptor opens chemically gated channels that allow entrance/exit of ions that cause hyperpolarization.
Temporal Summation
One or more presynaptic neurons transmit impulses in rapid-fire order.
Spatial Summation
Postsynaptic neuron is stimulated by a large number of terminals simultaneously
Synaptic Potentiation
Repeated use of synapse increases ability of presynaptic cell to excite postsynaptic neuron.
Presynaptic Inhibition
Release of excitatory neurotransmitter by one neuron is inhibited by another neuron via an axoaxonal synapse.
Acetylcholine (ACh)
First identified and best understood neurotransmitter; released at neuromuscular junctions, and used by many ANS and CNS neurons.
Biogenic Amines
Neurotransmitters including catecholamines (dopamine, norepinephrine, epinephrine) and indolamines (serotonin, histamine).
Amino Acids (as neurotransmitters)
Glutamate, aspartate, glycine, GABA.
Peptides (Neuropeptides)
Strings of amino acids with diverse functions, e.g., Substance P, endorphins, gut-brain peptides.
Purines (as neurotransmitters)
Monomers of nucleic acids, e.g., ATP and adenosine.
Gasotransmitters
Gases such as nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) that act as neurotransmitters.
Endocannabinoids
Lipid-soluble neurotransmitters that act at the same receptors as THC.
Neuromodulator
Chemical messenger released by neuron that does not directly cause EPSPs or IPSPs but instead affects the strength of synaptic transmission
Channel-Linked Receptors
Ligand-gated ion channels; action is immediate and brief.
G Protein-Linked Receptors
Responses are indirect, complex, slow, and often prolonged; involves transmembrane protein complexes and cause widespread metabolic changes.
Neuronal Pool
Functional groups of neurons that integrate incoming information from receptors or other neuronal pools and forward processed information to other destinations.
Discharge Zone
Neurons closer to incoming fiber are more likely to generate impulse.
Facilitated Zone
Neurons on periphery of pool are farther away from incoming fiber; usually not excited to threshold unless stimulated by another source.
Serial Processing
Input travels along one pathway to a specific destination; best example is a spinal reflex.
Reflex Arc
The pathway over which reflexes occur, including receptor, sensory neuron, CNS integration center, motor neuron, and effector.
Parallel Processing
Input travels along several pathways; different parts of circuitry deal simultaneously with the information.
Diverging Circuit
One input, many outputs; an amplifying circuit.
Converging Circuit
Many inputs, one output; a concentrating circuit.
Reverberating Circuit
Signal travels through a chain of neurons, each feeding back to previous neurons; an oscillating circuit.
Parallel After-Discharge Circuit
Signal travels along several pathways to a common output; bursts of impulses after stimulation has ended.
Growth Cone
Prickly structure at tip of axon that allows it to interact with its environment.
Apoptosis
Programmed cell death.