Histology and Glial Cells

What are the two main cell types that compose neural tissue?

glial cells and neurons

What is the general function of neural tissue?

communicate with and control of other body tissues

What are the general functions of glial cells?

Provide a supportive scaffold for neurons.

Cover all non-synaptic sections of neurons, isolating the activity occurring in each neuron from activity in adjacent neurons.

Are all glial cells found in both the CNS and PNS?

No, some glial cells are found only in the CNS and some only in the PNS

Name the glial cells found in the CNS.

astrocytes, ependymal cells, microglia, and oligodendrocytes.

What is the most abundant glial cell type in the CNS?

Astrocytes

Describe the structure of astrocytes.

are star-shaped cells with like-to extensions

What is one function of astrocyte extensions that surround capillaries in the CNS? What does this structure form?

produce an extra barrier between blood plasma and interstitial fluid called the blood-brain barrier.

What is the function of the blood-brain barrier?

is a strict barrier that prevents many molecules from entering the CNS

What is one function of astrocyte extensions that surround neurons in the CNS?

provide support by maintaining the extracellular fluid around the neurons

Describe ependymal cells. Where are they found?

ciliated cells that surround capillaries in hollow, fluid-filled spaces in the brain called ventricles.

What is the function of ependymal cells?

produce and secrete cerebrospinal fluid (CSF). The motile cilia on ependymal cells circulate CSF

What is the role of cerebrospinal fluid (CSF) in ependymal cells in the CNS?

acts like blood in the CNS

What type of cells are microglia? Where are they found?

are immune cells in the CNS.

What is the function of microglia?

use phagocytosis to remove foreign cells, dead/dying cells, and debris

What are oligodendrocytes filled with? What do they do?

with a lipid called myelin and wrap around axons on neurons in the CNS to produce myelin sheaths.

What is the function of myelin sheaths?

provide electrical insulation to the neuron and help to heal minor damage to the neuron.

Name the glial cells found in the PNS.

satellite cells and Schwann cells.

Where are satellite cells found? What is their function?

surround neuron cell bodies in ganglia and provide support to neurons by maintaining the extracellular fluid around the neurons

What do Schwann cells do? Where are they found?

wrap around axons on neurons in the PNS to produce myelin sheaths.