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