Nervous Tissue Flashcards
What is the purpose of nervous tissue?
conduction of nerve impulses to relay information
What germ layer is nervous tissue derived from?
ectoderm
What is nervous tissue made of?
neurons and neuroglia
What is the cell body of a neuron called?
perikaryon or soma
Which type of neuron is most common?
multipolar
How are neurons classified?
according to the number of dendrites (polarity)
What is the ratio of neuroglia to neurons?
10:1
What are the four types of neuroglial cells?
oligodendrocytes, astrocytes, ependymal cells, microglial cells
What forms the myelin in the CNS?
oligodendrocytes
What is the purpose of myelin?
insulates the axon, and facilitates transmission of electrical signals
What cell is star-shaped and forms the BLOOD BRAIN BARRIER?
astrocytes
What cell lacks tight junctions, and forms the cuboidal epithelium of the CNS and the CSF?
ependymal cells
What cell is phagocytic and is the brain’s “garbage collector”?
microglial cells
In the brain, what type of matter is on the periphery?
grey matter
What makes up white matter?
myelinated AXONS and myelin-producing oligodendrocytes
What makes up the granular layer of grey matter?
LOTS OF small neurons and Purkinje cells
What makes up the peripheral nervous system?
nerves, ganglia, nerve endings
What is a collection of neuron cell bodies?
ganglia
What is an Auerbach’s plexus?
when a ganglia is between 2 smooth muscle layers
In the PNS, what makes myelin?
Schwann cells
Which neuroglial cell has a role in immune defense and can be phagocytic?
microglia
In the PNS, what are the collections of cell bodies?
ganglia
When a ganglia is between two muscle layers, what is it called?
Auerbach’s plexus
