Nervous System
Oligodendrocyes Ependymal cells Microglia Astrocytes Schwann Cells Satellite Cells
Name the 6 kinds of neuroglia
functional deficit
Nerve injury is often followed by some degree of _______________
regeneration tube
The _________________ guides the growing sprout back to the original target cells, reestablishing synaptic contact.
schwann cells
The _________________ produce cell-adhesion molecules and nerve growth factors that enable a neuron to regrow to its original destination.
neurilemma
The schwann cell's plasma membrane does not spiral, but folds once around each fiber and somewhat overlaps itself along the eges. This wrapping is the ______________
gliomas
___________ usually grow rapidly and are highly malignant.
schwann cells
aid in the regeneration of damaged nerve fibers
Myelin sheath
an insulating layer around a nerve fiber, somewhat like the rubber insulation on a wire.
Protein-synthesizing organelles
are limited to the soma
myelination
begins in the 14th week of fetal development, yet hardly any myelin exists in teh brain at the time of birth.
Oligodendrocytes
form myelin in brain and spinal cord
schwann cells
form neurilemma around all PNS nerve fibers and myelin around most of them
astrocytes
form supportive framework for nervous tissue; have extensions called perivascular feet
myelin sheath
formed by oligodendrocytes in the CNS and schwann cells in the PNS
regeneration tube
formed by schwann cells, basil laminae, and neurilemma: enable neuron to regrow to its original destination when growth process reaches it.
Astrocyes
induce formation of blood-brain barrier; nourish neurons; produce growth factors that stimulate neurons
Astrocytes
cover brain surface and nonsynaptic regions of neurons; form supportive framework in CNS
Oligodendrocytes
each process reaches out to a nerve fiber and spiral around it like electrical tape wrapped repeatedly around a wire.
Schwann cells
envelop nerve fibers of the PNS
blood-brain barrier
isolates the blood from the brain tissue and limites what substances are able to get to the brain cells, thus protecting the neurons
Ependymal cells
line cavities of brain and spinal cord; secrete and circulate cerebrospinal fluid
Astrocytes
remove K+ and some neurotransmitters from ECF of brain and spinal cord; help to regulate composition of ECF; form scar tissue to replace damaged nervous system.
Oligodendrocytes
somewhat resembles an octopus; that have a bulbous body with as many as 15 armlike processes
Myelin
speeds signal conduction
Neuroglia or Glial Cells
supporting cells of the nervous system
satellite cells
surround somas of neurons in the ganglia; provide electrical insulation and regulate chemical environment of neurons
Satellite cells
surround the neurosomas in ganglia of the PNS
Astrocytes
the most abundant glial cells in the CNA and constitute over 90% of the tissue in some areas of the brain
nodes of Ranvier
the myelin sheath is segmented - the gaps between the segments are called
astrocytosis
the process of ____________, when neuron is damaged, astrocytes form hardened scar tissue and fill space formerly occupied by the neuron
astrocytes
they have the most diverse functions of any glia
centripedal mylenation
this is the kind of mylenation by the oligodendrycyte
centrifugal mylenation
this is the kind of mylenation by the schwann cell
gliomas
Most adult brain tumors are composed of glial cells which are mitotically alive throughout life. Such tumors are called _____________
Oligodendrocytes Ependymal Cells Microglia Astrocytes
4 types of neuroglia found only in the CNS
protein synthesis
As a result of nerve fiber injury - the distal fiber degenerates as do its schwann cells, which are dependent on _____________ for their maintenance
unmyelinated
Many nerve fibers in the CNS and PNS are ________.
Schwann Cells Satellite Cells
2 types of glial cells found only in the PNS
blood-brain barrier
Because of the __________________, brain tumors usually do not yield to chemotherapy and must be treated with radiation or surgery.
CNS, PNS
Damaged nerves in the _______cannot regenerate at all, but since it is enclosed in bone, it suffers less trauma than ________.
schwann cells
In addition to myelinating peripheral nerve fibers, ________________ assist in the regenerating of damaged fibers.
perivascular feet
contact the blood capillaries and stimulate them to form a tight seal called the blood-brain barrier
denervation atrophy
muscle fibers deprived of their nerve supply exhibit a shrinkage called _____________
astrocytes
named for their many-branched, somewhat starlike shape
myelination
production of myelin sheaths
satellite cells
provide electrical insulation around the soma and regulate the chemical environment of the neurons
astrocytes
secrete proteins called nerve growth factors
