nervous tissue: exam 4(final) Flashcards
what is the function of neurons?
they are signal sending and receiving cells
what is the cell body of a neuron?
it contains the nucleus, does basic cell functions, and can receive signals (neurons)
what are dendrites?
they are branched structures off of cell body, they receive signals. (neurons)
what is the funnel shaped area of a neuron that extends from the cell body to axon, signals to be sent start here?
axon hillock (neurons)
what is an axon?
it is a long projection that extends out to contact other cells, signals travel down axon (neurons)
what are the expanded regions at the end of an axon that are the contact points with other cells and pass signals to other cells?
axon terminals (neurons)
what is the myelin sheath?
it is a coating of fat on axon, made by other cells, its purpose is to speed up signals. (neurons)
what are bare patches of axon in the myelin sheath?
nodes (neurons)
what are multipolar neurons?
they have lots of dendrites, one axon, multi purpose
what are bi polar neurons?
they have one fat dendrite (may have branches), and one axon, always sensory.
what are unipolar neurons?
cell body is off to the side of one long combined axon/dendrite, these are all sensory, their job is to pass the signals to one place to another
what is neuroglia?
all support cells that help out neurons
what are astrocytes?
part of CNS neuroglia- (star cells) have lots of projections, some projections touch the neurons, help keep neurons with metabolism. some projections cover entire surface of CNS capillaries- creates blood brain barrier. anything in blood must filter through the astrocytes to get to brain tissue. (neuroglia)
what are oligodendrocytes?
few projection cells, projections wrap axons of neurons to form the myelin sheath, one oligodendrocyte can wrap a small part of multiple axons (neuroglia CNS)
what crawl around the CNS looking for pathogens then turn into macrophages and eat the pathogens (phagocytosis), and are immune cells?
microglia (neuroglia)
what lines the hollow spaces in the CNS, they produce the cerebral spinal fluid, they have cilia that moves the fluid?
ependymal cells (neuroglia)
what type of cells are on the cell body of neuron, support metabolism of neuron?
satellite cells (PNS neuroglia)
what are neurolammocytes also know as shwann cells?
they form the myelin sheath of axons in the PNS, each shwann cell is on one axon only (doesn’t reach out to other axons)
what is a nerve fiber?
it is one axon + its myelin sheath
what is a nerve?
a bundle of nerve fibers in the PNS wrapped in connective tissue
what is ganglia?
collection of cell bodies in PNS wrapped in connective tissue
what is a tract?
its a bundle of nerve fibers in CNS not wrapped in connective tissue
what is nucleus of neurons?
collections of cell bodies in CNS no connective tissue
what is gray matter?
it is a large amount of cell bodies in the CNS
what is white matter?
it is a large area of axons in CNS
what is a synapse?
it is a connection between neurons, axon terminals of one cell come into contact with dendrites a cell body of another cell, signals are passed across synapses
