Study Questions and Key Points

This page provides a review of important concepts related to neuroglial cells and neurons in the nervous system.

Key points to remember:

1. Neuroglial cells do not carry or receive electrical impulses. Their primary function is to support and aid neurons in various ways.

2. The main types of neuroglia in the Central Nervous System (CNS) are:

   • Astrocytes: These wind around neurons and blood vessels, holding cells and structures together. They also contribute to the blood-brain barrier.

   • Ependymal cells: These line the ventricles in the brain and the central canal of the spinal cord, playing a role in cerebrospinal fluid circulation.

   • Oligodendrocytes: These wrap around selected CNS neurons, providing insulation (myelin) and increasing the speed of impulse transmission.

   • Microglia: These move through the CNS, engulfing and destroying potentially harmful particles and cellular debris.

Highlight: Each type of neuroglial cell has a specific function that contributes to the overall health and efficiency of the nervous system.

3. In the Peripheral Nervous System (PNS), the main types of neuroglia are:

   • Satellite cells: These wrap around neurons, forming ganglia and regulating the exchange of substances.

   • Schwann cells: These wrap around PNS neurons, providing myelin insulation.

4. Neurons are specialized cells that can generate, send, receive, and respond to electrical impulses. They consist of three main parts: the cell body (soma), dendrites, and axon.

5. Neurons can be classified based on their shape (unipolar, bipolar, multipolar), function (sensory, motor, association), myelination (myelinated, unmyelinated), and location (CNS, PNS).

Example: A motor neuron in the spinal cord would be classified as a multipolar, efferent, myelinated, CNS neuron.

Understanding these key points is crucial for grasping the structure and function of the nervous system and the roles played by its various cellular components.

Neuroglial Cells in the Nervous System

Neuroglial cells, also known as neuroglia, play a crucial supporting role in the nervous system. Unlike neurons, they do not carry information or impulses but are essential for maintaining and aiding neuronal function. This page provides an overview of the various types of neuroglial cells and their specific functions in the central nervous system (CNS) and peripheral nervous system (PNS).

Definition: Neuroglial cells are support cells in the nervous system that do not carry information or impulses but aid neurons in various ways.

The main types of neuroglial cells in the CNS include:

1. Astrocytes: These star-shaped cells wrap around neurons and blood vessels, providing structural support and contributing to the blood-brain barrier.

2. Ependymal cells: Cube-shaped cells with cilia that line the ventricles in the brain and the central canal of the spinal cord.

3. Oligodendrocytes: Cells that wrap around selected CNS neurons, providing them with a myelin sheath.

4. Microglia: Tiny cells that move through the CNS, engulfing and destroying potentially harmful particles and cellular debris.

In the PNS, the main types of neuroglial cells are:

1. Satellite cells: These cells wrap around neurons, forming ganglia and regulating the exchange of substances between neurons and their environment.

2. Schwann cells: Similar to oligodendrocytes in the CNS, these cells wrap around PNS neurons, providing myelin insulation.

Highlight: Neuroglial cells are more numerous than neurons and are more mitotically active when mature, meaning they can undergo cell division.

Vocabulary: Myelin - A white, fatty substance that forms an insulating layer around nerve fibers, increasing the speed at which impulses can travel through neurons.

The presence of myelin gives rise to the terms "white matter" and "gray matter" in the nervous system:

• White matter: Areas where myelinated neurons are concentrated, appearing white due to the myelin.
• Gray matter: Areas where unmyelinated neurons are concentrated, appearing gray or dark.

Understanding the types of neuroglial cells and their functions is crucial for comprehending the complex workings of the nervous system and its various components.