Glia_cells_Bio_G12_STEM_Nervous_tissues.pptx

Glia cells in the nervous tissue

1. Glia Cells Made by group: 2 Under supervision of Ms. Nardeen

2. Glia Cell Type Location Function Astrocytes CNS (Brain and Spinal Cord) Fill spaces between neurons, regulate the extracellular environment and synaptic transmission. Oligodendroglia Cells CNS (Brain and Spinal Cord) Provide myelin sheaths for multiple axons in the CNS. Microglia CNS (Brain and Spinal Cord) Act as immune cells, removing debris and responding to infections. Ependymal Cells CNS (Brain Ventricles) Line fluid-filled ventricles and help circulate cerebrospinal fluid (CSF). Schwann Cells PNS (Nerves outside CNS) Provide myelin sheaths for single axons in the PNS and assist in nerve repair and regeneration. Table 1: Glia Cells Based on Location

3. Glia Cell Type Myelination Status Function Oligodendroglial Cells Myelinating (CNS) Provide myelin to multiple axons in the CNS to speed up nerve impulse transmission. Schwann Cells Myelinating (PNS) Provide myelin to a single axon in the PNS, aiding in fast signal conduction and nerve repair. Astrocytes Non-Myelinating Regulate extracellular ion concentrations, remove excess neurotransmitters, and envelop synaptic junctions. Microglia Non-Myelinating Function as immune cells, clearing debris and protecting neurons from pathogens. Ependymal Cells Non-Myelinating Line brain ventricles and assist in the circulation of cerebrospinal fluid. Table 2: Glia Cells Based on Myelination

4. Glia cells in CNS 01 You can enter a subtitle here if you need it

5. Astrocytes : 1) Most numerous glia in the brain . 2) Fills the spaces between neurons , leaving only about 20 nm between astrocytes and neurons.

6. Function: Contain microfilaments → support neurons . Blood-brain barrier. ( Restricts the movement of substances between the blood and interstitial fluid of the CNS ). In the embryo they secrete chemicals that appear to regulate the growth, migration, and interconnection among neurons in the brain. Help to maintain the appropriate chemical environment for the generation of nerve impulses. By: A. regulate the concentration of important ions such as K+ B. take up excess neurotransmitters C. Serve as a conduit for the passage of nutrients and other substances between blood capillaries and neurons.

7. Oligodendrocytes Found only in the central nervous system (CNS). One oligodendroglial cell can myelinate multiple axons . Main function : Provide myelin sheaths around axons in the CNS. Myelin : A- insulates axons, allowing for faster propagation of nerve impulses . B- Structure : Myelin wraps around the axon like a spiral (sword in its scabbard analogy). C- Nodes of Ranvier : Periodic gaps in the myelin sheath where the axonal membrane is exposed, facilitating faster impulse transmission .

8. M icroglia Act as phagocytes (immune cells) in the brain. Function : Remove debris from dead or degenerating neurons and glial cells. Immune defense : Play a role in responding to infection or injury in the brain.

9. Ependymal Cells Line the fluid-filled ventricles of the brain. Help circulate cerebrospinal fluid (CSF) and may contribute to fluid homeostasis. Role in brain development : Guide cell migration during brain development.

10. Glia cells in PNS 02 You can enter a subtitle here if you need it

11. Schwann cell Found in the peripheral nervous system (PNS) , outside the CNS. Also provide myelin sheaths , but each Schwann cell myelinates only one axon . Essential for nerve repair and regeneration in the PNS.

12. Recovery

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