Final Test Flashcards
What is a neuron?
a nerve cell
this conducts impulses away from the cell body
axon
these receive messages from other neurons
dendrites
this is nervous tissue that provides physical support, insulation, and nutrients for neurons
neuroglia cells
where are microglia found and what do they do
CNS, phagocytize bacteria cells and cellular debris, form scars in damaged areas
where are oligodendrocytes found and what do they do
CNS, provide insulating layers of myelin called a myelin sheath
where are astrocytes found and what do they do
found between neurons and blood vessels, provide structural support, join parts by their cellular processes, help regulate nutrient and ion concentration, form scar tissue to CNS injuries
where are Ependymal cells found and what do they do
CNS, form epithelial-like membrane linings of ventricles in brain and central canal of spinal cord, blood-brain barrier blocks substances from entering the brain
where are Schwann cells found and what do they do
PNS, produce a myelin sheath around axons of myelinated neurons
This branch of the nervous system contains the brain and spinal cord.
Central Nervous System
This branch of the nervous system contains cranial nerves and spinal nerves.
Peripheral Nervous System
describe the integrative function of the peripheral nervous system
sensory information is used to create sensations, memories, thoughts, and decisions. Motor functions are then used to act on them
effectors of the PNS include ______
muscles and glands controlled by nerve impulses
sensory neurons are ______ and carry information to _____
afferent, CNS
motor neurons are ______, _______, and transmit impulses out of the ____ or _____ to ______
efferent, multipolar, brain, spinal cord, effectors
this is when impulses are conducted outward or away from the CNS
efferent
this is when impulses are conducted inward or toward the CNS
afferent
if a neuron responds, it responds _____
completely
If a stimulus threshold intensifies what stays the same and what increases
all action potentials maintain the same strength, but the number of action potentials per second increases
brief rest periods between action potentials that limit the frequency of action potentials and ensures they are going in the same direction
refractory period
common frequency for action potentials
100 impulses per second up to 700 impulses per second
this kind of neurotransmitter increases the postsynaptic membrane permeability to sodium ions, bringing the postsynaptic membrane closer to threshold to trigger nerve impulses
excitatory neurotransmitter
this kind of neurotransmitter is less likely to reach threshold, decreasing the chance of a nerve impulse
inhibitory neurotransmitter
Explain how a reflex works
receptors are excited and send a signal along the sensory neuron to the spinal cord, and then passed to a motor neuron which stimulated the reflex
