Question

Which kind of glia cells wraps around the synaptic terminals of axons?

• A. Astrocytes
• B. Microglia
• C. Oligodendrocytes
• D. Schwann Cells

Hint:

Remember the concept of the "tripartite synapse" which consists of: 1. Presynaptic membrane, 2. Postsynaptic membrane, and 3. Astrocytic processes wrapping them.

Answer 1

The Correct Option is A

Step 1: Understanding the Question:
The question asks us to identify the type of glial cell that physically wraps around and supports the synaptic junctions of neurons.

Step 2: Detailed Explanation:

• Astrocytes are star-shaped glial cells in the central nervous system that play a crucial role in maintaining synaptic structures.

• They extend processes that wrap around the synaptic cleft and synaptic terminals of axons, forming what is known as the "tripartite synapse."

• By wrapping around synapses, astrocytes isolate them chemically, uptake excess neurotransmitters (such as glutamate), and regulate ion concentrations (like potassium).

• Microglia function as the primary immune defense of the central nervous system, acting as phagocytes to clear cellular debris and pathogens.

• Oligodendrocytes produce the myelin sheath that insulates axons within the central nervous system.

• Schwann cells provide myelin sheathing for axons in the peripheral nervous system.

• Therefore, only astrocytes are physically positioned to envelop and chemically regulate synaptic terminals.

Step 3: Final Answer:
Astrocytes are the glial cells that wrap around the synaptic terminals of axons to assist in synaptic transmission and maintenance.