Chapter 3 Flashcards
Two major cell types in the brain
Glia and neuron
Function of glial cells
Glial cells serve many functions. For example, they supply nourishment to neurons, help remove neurons’ waste products, and provide insulation around many axons
Function of neurons
Individual cells in the nervous system that receive, integrate, and transmit information
Soma
cell body that contains the cell nucleus and much of the chemical machinery common to most cells
Dendrites
the parts of a neuron that are specialized to receive information
Axon
a long, thin fiber that transmits signals away from the soma to other neurons or to muscles or glands
Myelin sheath
insulating material that encases some axons
Terminal buttons
Small knobs that secrete chemicals called neurotransmitters
Synapse
a junction where information is transmitted from one neuron to another
Synaptic cleft
A microscopic gap between the terminal button of one neuron and the cell membrane of another neuron
The neurons send signals in this gap. The sender is called the presynaptic neuron and the receiver is called the post-synaptic neuron
Synaptic pruning
Old or less-active synapses withering away while new and often-used synapses stick around
Postsynaptic potential
Voltage change at a receptor site on a postsynaptic cell membrane
Neurotransmitters
Chemicals that transmit information from one neuron to another
Excitatory PSP (postsynaptic potential)
Positive voltage shift that increases likelihood of postsynaptic neuron firing action potentials
Inhibitory PSP (postsynaptic potential)
Negative voltage shift that decreases likelihood of postsynaptic neuron firing action potential
Reuptake
Synapses absorbing neurotransmitters after they trigger a response. This allows the chemical to be recycled
Resting potential of a neuron
its stable, negative charge when the cell is inactive
Action potential
A very brief shift in a neuron’s electrical charge that travels along an axon
The absolute refractory period
The minimum length of time after an action potential, during which another action potential cannot begin. This “down time” isn’t very long, only 1 or 2 milliseconds.
All-or-none law
The neural impulse is an all-or-none proposition, like firing a gun. You can’t half-fire a gun
Even though the action potential is an all-or-nothing event, neurons can convey information about the strength of a stimulus by varying the rate at which they fire action potentials
What are nerves?
Nerves are bundles of neuron fibers (axons)
What is the central nervous system?
Brain and spinal cord
What are the parts of the hindbrain?
Includes the cerebellum, the medulla, and the pons
Functions of the cerebellum
Contributes to coordination and critical to the sense of equilibrium
Funciton of the Medulla
Controls breathing, maintaining muscle tone, and regulating circulation