Nervous System (General) Flashcards
What are ganglion?
Clusters of cell bodies in the peripheral nervous system
What is a nucleus?
a cluster of cell bodies in the central nervous system; is post-mitotic, therefore cannot replicate itself; connected to synapses, not cytoplasm
What are nerves?
A collection of neuron axons in the PNS
What are tracts?
Collections of neuron axons in the CNS
How would you describe sensory nerves that are directed towards the brain?
afferent
What would you consider tracts that move away from the brain?
efferent
What is grey matter?
Nervous tissue that has unmyelinated neuronal cell bodies and axons (such as the neocortex)
What is white matter?
Myelinated axons with neuronal tracts
What are layers or nuclei?
well-defined group of neuronal cell bodies (many, vs. nucleus of neuron)
What is the parenchyma?
the tissues/cells associated with brain function e.g. neurons and glia)
What is, and what does a neuron do?
an individual cell that is ‘electrically irritable’ communicating and computing cells of nervous system
What is, and what is the function of glia?
Supporting cells for immune and structural support (prevents infections, etc.) which aid in the transfer of materials from blood to neurons, etc.
What are the 3 main types of functional cells?
Sensory, motor, and interneurons
What are sensory neurons?
Afferent neurons that carry info. from receptors in the PNS to the brain
What are motor neurons?
efferent neurons that carry signals from the brain (CNS) to the muscles
What are interneurons?
Those which are not connected only to other neurons, not muscles or receptors
What is the morphologic diversity of neurons
the shape of neurons, and their arborization
What is described as a highly-arborized neuron?
Those which are densely-branched, and therefore with many dendrites for a multitude of channels, as opposed to highly-specialized neurons in low-arborization
What would you consider s neuron that has two facets?
bipolar neuron
What is an astrocyte?
a star-shaped glia cell which regulates the transmission of electrical impulses within the brain
What are microglia?
Tiny cells in the brain (roughly encompassing 10 - 15% of brain cells) which are macrophages of foreign bodies, acting as a main defense in CNS
What are macrophages?
cells which takeover foreign cells, etc. by ‘eating’ them; usually a process of immunal support
What are ependymal cells?
Cells which line the cerebrospinal fluid-filled ventricles in the brain, and central canal of the spinal cord; nervous tissue cells with ciliated simple columnar form like mucosal or epithelial cells
What are oligodendrocytes?
Cells which wrap around a select few cells, which cannot regenerate if damaged (in the CNS); provide support and insulation to axons in CNS of some vertebrates
What are Schwann cells?
Cells on the PNS that wrap around cells to provide support and insulation to the axons, and can regenerate of damaged; similar to the oligodendrocytes of the CNS
What are myelin sheath composed of?
80% lipid, 20% protein
What are neural units?
Those individual units in the brain (rather thsn the rest of the body)that contain specialized features: dendrites, axons, cell body
What is the law of dynamic polarization?
the idea that neurons are directed by the dendritic tree, followed by the axons, flowed by synaptic terminals, being depicted from left to right
What are synapses?
Barriers to transmission between two neurons
What is the unity of transmission idea?
The idea that if a neuron passes as excitstoru or inhibitory, it will continue to be so because the probability of neural transmission is either likely or not, respectively
What is Dale’s Law?
The idea that each nerve terminal in a neuron releases a single type of transmitter
What is an axon?
A structure in neural transmission that is between the hillock and a dendrite of another neuron
What is cytoplasm?
jelly-like substance that runs along the axon
What is the non-cytoplasm material that is found near the synaptic cleft?
The interstitium (found in interstitial spaces)
What is neural activity that belongs to the preceding neuron in an exchange?
The presynaptic membrane
What is neural activity that belongs to the proceeding neuron in an exchange?
Postsynaptic membrane
What is the central nervous system composed of?
the brain and the spinal cord
What is the peripheral nervous system composed of?
the sensorimotor or somatic nervous system, as well as the autonomic nervous system
What is the parasympathetic nervous system?
The part of the peripheral nervous system that balances internal/ organs
What is the circular structure that cradles neural transmitters as it moves along the neuron?
the Circle of Willis?
What supports the central nervous system?
the skull and vertebrae
What part of the brain is the neurocranium, and what is it?
found in the posterior portion of the skull, it protects the brain and is inflexible in adults, but not in newborns to ensure the successful travek through the birth canal
What composes the vertebral column?
33 articulated bones that are flexible, and protect the spinal cord
What are the meninges?
3 membranes that enclose the CNS
What is the Dura Mater?
The outer layer of the meninges, a membrane that encloses the CNS in the brain