Biology Chapter 4: The Nervous System Flashcards
What are neurons?
Highly specialized cells responsible for conduction of impulses.
How do neurons communicate using electrical communication?
Via ion exchange and the generation of membrane potentials down the length of the axon.
How do neurons communicate using chemical communication?
Via neurotransmitter to the postsynaptic cell and the binding of these neurotransmitters to the postsynaptic cell
What are dendrites?
Appendages that receive signals from other cells
What is the soma?
location of the nucleus as well as organelles, including the ER and ribosomes
What is the axon hillock?
Where the cell body transitions to the axon and where action potentials are initiated
What is the axon?
It is a long appendage down which an action potential travels.
What is the nerve terminal or synaptic bouton?
End of the axon from which neurotransmitters are released.
What are nodes of ranvier?
exposed areas of myelinated axons that permit saltatory conduction.
What is the synapse?
nerve terminal of the presynaptic neuron, the membrane of the postsynaptic cell and the space between called the synaptic cleft
What is myelin?
It is an insulating substance that prevents signal loss. Prevents dissipation of the neural impulse and crossing of neural impulses from adjacent neurons.
What is myelin created by?
oligodendrocytes in the central nervous system and Schwann cells in the peripheral nervous system
What are axons bundled into?
Nerves or tracts
What is the difference between nerves and tracts?
Nerve may carry multiple types of information - cell bodies of the same type cluster in ganglia in the PNS
Tracts contain only one type of information - cluster in nuclei in the CNS
What are neuroglia?
cells within the nervous system in addition to neurons
What are astrocytes?
nourish neurons and form the blood-brain barrier , which controls the transmission solutes from the bloodstream into the nervous tissue
What are ependymal cells?
line the ventricles of the brain and produce cerebrospinal fluid, which physically supports the brain and serves as a shock absorber.
What are microganglia?
phagocytic cells that ingest and break down waste products and pathogens in the CNS
What is the resting membrane potential of neurons?
-70 mV
What maintains the resting potential of neurons?
Maintained using selective permeability of ions as well as the Na+/K+ pump, which pumps three sodium ions out of the cell for every two potassium in
What are the two types of incoming signals?
Excitatory signals that cause depolarization of the neuron
Inhibitory signals that cause hyperpolarization of the neuron
What is temporal summation?
the addition of multiple signals near each other in time
What is spatial summation?
the addition of multiple signals near each other in space
What is an action potential?
It is used to propagate signals down the cell