A&P Final: Neuroglia/Glial Cells

What are neuroglia

Support cells of nervous tissue

Are neuroglia smaller or larger than neurons

Smaller

Are neuroglia more or less numerous than neurons

Much more numerous (50 x more)

Can neuroglia divide

Yes

Do neuroglia generate action potentials

No

Why are glial tumors common

Glial cells can divide rapidly by mitosis

What are CNS glial cells

• Astrocytes

• Oligodendrocytes

• Microglia

• Ependymal Cells

What are PNS glial cells

Schwann cells and satellite cells

What are astrocytes

Star-shaped CNS glial cells (largest and most numerous)

What do astrocytes connect with?

Capillaries, neurons, synaptic endings, pia mater.

What are the two types of astrocytes?

1. Protoplasmic

2. Fibrous

Where are protoplasmic astrocytes found

Gray matter

Where are fibrous astrocytes found

White matter

What are the major functions of astrocytes

Structural support, nutrient exchange, blood-brain barrier, neurotransmitter metabolism, neuronal transmission, learning/memory, neuronal migration/growth, repair.

What glial cells help form the blood-brain barrier?

Astrocytes

How to astrocytes help form the BBB?

They wrap around endothelial cells and secrete chemicals that maintain selective permeability.

What are oligodendrocytes

CNS glial cells that form myelin around multiple CNS axons.

What are the CNS myelin-forming cells

Oligodendrocytes

PNS myelin-forming cells

Schwann Cells

What do oligodendrocytes inhibit?

Axonal regrowth in the CNS.

What are microglia?

Small CNS glia with protective/phagocytic functions.

What are the functions of microglia?

Clear dead cells, debris, invading microorganisms, and damaged nervous tissue.

Microglia are related to what immune cells?

Macrophages and monocytes.

What are ependymal cells?

Cuboidal/columnar cells lining ventricles and the central canal.

What do ependymal cells help circulate?

Cerebrospinal fluid.

Ependymal cells line what structures?

Ventricles of the brain and central canal of the spinal cord.

Ependymal cell function:

Secretion and monitoring of CSF and barrier between CSF and CNS interstitial fluid.

What are Schwann Cells

PNS glial cells that encircle axons and produce myelin

What is the neurolemma

Outer layer of Schwann cell/myelin sheath in PNS

Why is the neurolemma important?

Helps guide regeneration after Injury.

What are satellite cells?

Flat cells surrounding the neuron cel bodies in peripheral ganglia.

Function of satellite cells

Structural support and regulation of exchange between neuron cell bodies and interstitial fluid.