The Neuron Flashcards
Structure of neurons and chemistry at rest
What is another name for the cell body?
The soma
What is the name of where the cell body joins the axon?
Initial segment/ Axon Hillock
What are collaterals of the neuron?
Branches from axon; more collaterals are present closer to end of the neuron = more influence
What are processes?
Long extensions
What is the myelin sheath?
Layers of modified plasma membrane, comprised of Glial cells
What cells are the myelin sheath comprised of in the PNS?
Schwann cells
What cells are the myelin sheath comprised of in the CNS?
Oligodendrocytes
What direction do afferent neurons run in?
Towards CNS; are sensory neurones
What part of the afferent neurons is in the CNS?
Central process (axon) enters CNS
What parts of the afferent neurons are in the PNS?
Cell body and peripheral process (dendron) are in PNS
What direction do efferent neurons run in?
Away from CNS; are motor neurons
What parts of the efferent neurons are in the CNS?
Cell body and its dendrites are located in the CNS
What part of the efferent neurons is in the PNS?
Axon is in the PNS, extended peripherally
Where are interneurons located?
Within the CNS
What are interneurons?
Relay neurons; signal changers/integrators; process information
What does the number of interneurons indicate about the complexity of the required action?
More interneurons in a pathway indicates increased complexity of action
What is the ratio of afferent: efferent: interneurons?
1 afferent: 10 efferent: 200,000 interneurons
What are the four main glial cells?
Oliodendrocytes, ependymal, microglia, astrocytes
What are oliodendrocytes?
Make up the myelin on axins
What are ependymal cells?
Line fluid-filled cavities; regulate production and flow of CSF
What are microglia?
Macrophage-like cells which perform immune function for nervous system
What are astrocytes?
Regulate extracellular fluid composition, especially at the end of the neuron, by removing K+ and NTs around the synapse; Form blood-brain barriers at capillary walls to protect neuron; Metabolically sustain neurons by providing glucose and removing ammonia; Guide neurons as they migrate to destination, and stimulate neuronal growth in embryos
What is polarity?
Intracellular charge
What is value?
The potential difference