Neuroglial Cells Classification

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Questions and Answers

Which type of neuroglial cell is categorized as a protoplasmic astrocyte?

Choroidal epithelial cell

Fibrous astrocyte (correct)

Ependymocyte

Oligodendrocyte

What is the primary function of oligodendrocytes in the central nervous system?

Support neuronal metabolism

Remove debris from neuronal injury

Form myelin sheaths around axons (correct)

Generate synaptic connections

Which cell type is derived from neuroepithelial stem cells during gliogenesis?

Astrocytes

Ependymal cells

Both A and B (correct)

Microglial cells

In the peripheral nervous system, which neuroglial cells are known for their role in myelination?

Schwann cells Signup and view all the answers

Which of the following neuroglial cells is involved in the immune response in the central nervous system?

Microglial cells Signup and view all the answers

What role do perineural satellite cells serve in the peripheral nervous system?

Provide structural support to neurons Signup and view all the answers

Which type of neuroglial cell is least likely to be involved in myelination within the central nervous system?

Astrocytes Signup and view all the answers

The process of Wallerian degeneration primarily involves what?

Degeneration of the axon distal to the injury site Signup and view all the answers

What classification indicates that a peripheral nerve injury is characterized by complete interruption of the nerve structure?

Neurotmesis Signup and view all the answers

Which condition is primarily associated with difficulties in swallowing?

Dysphagia Signup and view all the answers

What is one reason why axonal regeneration is not possible in the CNS?

Presence of inhibiting proteins in myelin Signup and view all the answers

Which of the following statements about demyelination is true?

Demyelination can cause axons to stop transmitting action potentials. Signup and view all the answers

What is a hallmark of Seddon's class I peripheral nerve injury?

Complete recovery with no damage to the axon Signup and view all the answers

What shape do active microglial cells typically exhibit?

Amoeboid Signup and view all the answers

Which cellular component is prominent in active microglial cells?

Secondary lysosomes Signup and view all the answers

What is one of the primary functions of active microglial cells?

Phagocytize neuronal debris Signup and view all the answers

In what pathological states do active microglial cells release proinflammatory mediators?

During inflammation, tumors, or edema Signup and view all the answers

What term is used for inactive microglial cells in a normal state?

Resting microglial cells Signup and view all the answers

Which neurodegenerative diseases are associated with active microglial functions?

Alzheimer's and Parkinson's Signup and view all the answers

What molecular signaling molecules do active microglial cells involve in their functions?

Cytokines and chemokines Signup and view all the answers

Which feature distinguishes active microglial cells from other glial cells during their activation?

Shape and prominence of secondary lysosomes Signup and view all the answers

What is the primary function of the Blood-Brain Barrier?

To prevent toxins and certain drugs from entering the brain Signup and view all the answers

Which cells are responsible for the production of myelin in the central nervous system?

Oligodendrocytes Signup and view all the answers

What is the significance of myelination in adult neurons?

It enhances the stability of connections between neurons Signup and view all the answers

What type of cells line the ventricles of the brain and produce cerebrospinal fluid?

Ependymal cells Signup and view all the answers

Which characteristic defines oligodendrocytes?

They can wrap around multiple axons through their processes Signup and view all the answers

Which of the following statements about ependymal cells is true?

They are cuboidal to columnar in shape and help in CSF production Signup and view all the answers

What limits the ability of substances like amoxicillin from entering the bloodstream in the brain?

Formation of the Blood-Brain Barrier Signup and view all the answers

What discovery method was used to identify oligodendrocytes?

Metallic impregnation techniques Signup and view all the answers

What type of information do ascending tracts primarily carry?

Sensory information such as pain Signup and view all the answers

What is the primary role of descending tracts?

To control voluntary muscle movements from the brain Signup and view all the answers

Which cells become amoeboid when activated in response to injury?

Microglial cells Signup and view all the answers

During Wallerian degeneration, which process does NOT occur?

Formation of new synaptic connections Signup and view all the answers

In the context of the nervous system, what are Schwann cells primarily associated with?

Myelination of peripheral nerves Signup and view all the answers

What is NOT a characteristic of the ascending tracts?

They connect the brain to motor organs Signup and view all the answers

Which type of tract would be responsible for conveying a sensation of touch from the hand to the brain?

Ascending sensory tract Signup and view all the answers

What happens to the distal part of a transected motor axon during degeneration?

It degenerates Signup and view all the answers

Study Notes

Main Cells of the Nervous System

Nerve cells (neurons) serve as the structural and functional unit of the nervous system.
Neuroglial cells provide support and insulation to neurons and are classified into two categories: CNS and PNS types.

Classification of Neuroglial Cells

In the CNS, glial cells include:
- Astrocytes: Comprising protoplasmic and fibrous types.
- Oligodendrocytes: Form myelin sheath around multiple axons.
- Ependymal Cells: Cuboidal to columnar in shape, line brain ventricles, and produce cerebrospinal fluid (CSF). Types include ependymocytes, tanycytes, and choroidal epithelial cells.
- Microglial Cells: Act as immune cells of the CNS, involved in phagocytosis of debris and inflammation.
In the PNS, glial cells include:
- Schwann Cells: Myelinate single axons.
- Satellite Cells: Support neuronal cell bodies in ganglia.

Blood-Brain Barrier

A vascular membrane that restricts the entry of toxins and drugs into the brain, functioning as a crucial gatekeeper.
Amoxicillin cannot penetrate this barrier, illustrating its selectivity.

Myelination

Oligodendrocytes are responsible for myelination in the CNS, wrapping around multiple axons.
Myelination enhances conduction speed and stability of nerve impulses, allowing mature neurons to function efficiently.

Ependymal Cells

Ependymal cells are important for CSF production and distribution.
They create the choroid plexus within the brain's ventricles.

Microglial Cells

Activated microglial cells take on an amoeboid shape to engulf pathogens and debris, crucial during inflammation and infection.
Regular expression of markers such as Lectin RCA-1 helps identify these cells in a resting state.

Wallerian Degeneration

Following injury in the PNS, the distal axon degenerates, Schwann cells dedifferentiate, and macrophages clear debris.
This process is critical for potential regeneration within peripheral nerves.

Demyelination

Refers to the loss of myelin insulation around axons, leading to slower nerve impulse transmission and, in some cases, complete loss of action potentials.
Myelin proteins in the CNS inhibit regeneration, explaining why CNS nerve injuries do not repair effectively.

Gliogenesis

This process involves the generation of glial cells from neural progenitor cells during CNS development, transitioning from neurogenesis to gliogenesis after neurons are formed.

Clinical Correlation

Understanding the roles and classifications of neuroglial cells is essential for addressing neurodegenerative diseases, such as Alzheimer's and Parkinson's, where microglial cells play significant roles in pathology.

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Description

Test your knowledge on the classification of neuroglial cells, focusing on their roles and types in the central nervous system. This quiz will cover the main cells of the nervous system, including both nerve cells and neuroglial cells, with a special emphasis on astrocytes and protoplasmic variations.