Neurons and Glial Cells Quiz

Neurons and Glial Cells

• The nervous system is made up of neurons and glia.

• Neurons are specialized cells that can receive and transmit chemical or electrical signals.

• Glia provide support functions for neurons and may assist in some of the signaling functions of neurons.

• Neurons communicate via both electrical signals (action potentials) and chemical signals (neurotransmitters).

• Dendrites are tree-like structures that receive neurotransmitters from other neurons.

• Synapses are specialized junctions where neurotransmitters are released from one neuron to pass the signal to the next neuron.

• An axon is a tube-like structure that propagates the integrated signal to specialized endings called axon terminals.

• Neuronal communication depends on the connections that neurons make with one another.

Communication Between Neurons

• Neurons communicate via both electrical and chemical signals.

• The three general phenomena required for communication between neurons are resting potential, action potential, and neurotransmitters.

• The resting potential is the membrane potential in a neuron that is not currently transmitting a signal.

• An action potential is a brief depolarization along the neuron’s axon that sends the signal to the next neuron.Neurotransmission and Synaptic Communication

• GABA is a neurotransmitter that, when released from a presynaptic neuron, binds to and opens Cl- channels, allowing Cl- ions to enter the cell and hyperpolarize the membrane.

• Neurotransmitters must be removed from the synaptic cleft after neurotransmission has occurred. This can be done through diffusion, enzymatic degradation, or recycling by the presynaptic neuron.

• EPSPs and IPSPs are graded and vary in magnitude of depolarization or hyperpolarization.

• Action potentials are all-or-nothing events.

• Summation in time occurs when multiple EPSPs or IPSPs from the same presynaptic neuron add up over time to reach the threshold for an action potential.

• Summation in space occurs when EPSPs or IPSPs from multiple presynaptic neurons add up simultaneously to reach the threshold for an action potential.

• Spatial summation can occur through convergence of multiple presynaptic neurons onto a single postsynaptic neuron.

• Temporal summation can occur through repeated firing of a single presynaptic neuron.

• Glutamate is an excitatory neurotransmitter that binds to and opens Na+ channels, allowing Na+ ions to enter the cell and depolarize the membrane.

• Acetylcholine is an excitatory neurotransmitter that binds to and opens Na+ channels, allowing Na+ ions to enter the cell and depolarize the membrane.

• Dopamine is a neurotransmitter involved in reward and motivation that can be released from neurons in the ventral tegmental area and bind to receptors in the nucleus accumbens.

• Serotonin is a neurotransmitter involved in mood regulation that can be released from neurons in the raphe nuclei and bind to receptors throughout the brain.