Section 43.1.2 (Exam 4) Neurons Flashcards
Neurons and Glia Are Unique Cells of Nervous Systems
What forms a synapse?
Axon terminals come extremely close to the membrane of a target/postsynaptic cell
What are the three cells that the postsynaptic or target cell could be?
Another neuron
A muscle cell
A secretory cell
How does the synapse of an AP transfer information from the presynaptic cell to the postsynaptic cell?
Electrically or chemically
Describe electrical synapses.
Electrical synapses allow the action potential to pass directly between two neurons
Describe chemical synapses.
An AP causes the terminal to release neurotransmitter chemicals which diffuse to receptors on the postsynaptic cell
Binding of the neurotransmitter to the postsynaptic cell may excite or inhibit it
Neurons integrate information by summing excitatory and inhibitory inputs
Glial cells possibly outnumber neurons in humans. There are many types. What are the 4 types of macroglia?
Oligodendrocytes
Schwann cells
Ependymal cells
Astrocytes
What is the function of oligodendrocytes?
Oligodendrocytes wrap around neuron axons, forming concentric layers of insulating cell membrane
What are the function of Schwann cells?
Schwann cells wrap the axons of other nerves (peripheral nerves)
What do oligodendrocytes and Schwann cells both produce?
Myelin (a type of cell membrane) that covers axons (glistening white appearance)
Not all neurons myelinated
What does myelin do?
Provides electrical insulation to the neuron
Some diseases impact myelin. Describe the impact and name one disease that does so.
affect myelin and impair conduction of action potential
Multiple sclerosis (MS)
Describe ependymal cells.
Line the central fluid filled chambers (ventricles) in the brain
Produce cerebrospinal fluid
Describe the purpose of astrocytes.
Contribute to the blood-brain barrier, which protects the brain from toxic substances in the blood
Aside from the blood-brain barrier, what are the additional functions of astrocytes?
They can take up neurotransmitters from the synapse and thus control communication between pre- and postsynaptic cells; Tripartite synapse
Store glycogen that can supply neurons with fuel
Release neurotransmitters that can alter the activities of neurons
Aid in repair and regeneration of neurons
Make contact with both blood vessels and neurons and signal changes in blood composition
