Cells of the Nervous System

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Types of CNS Cells:

• Two types of cells in the CNS are nerve cells (or neurons) and neuroglia (or glia).


• They are specialized cells for rapid communication.

• Dendrites and axons communicate signals away and toward the cell body.

• In the CNS, neuronal bodies occur in the grey matter, and neuronal axons occur in the white matter.

• Resting membrane potential = - 70 mV

• Membrane potential in axon during action potential is + 40 mV

• Myelinated axons = rapid (saltatory conduction)

• Hyperpolarization = more + membrane potential = less likely to induce an impulse.

• Transected axons fail to completely regenerate.

• Some neurons have no axons and conduct impulses in all directions.

• Neurite = neuronal axon or dendrite.

• Neurons exist in different shapes and sizes.

• Axons are very difficult to see in cadavers, so they have to be stained with dyes.

• Impulses are transmitted trough the cell membrane.

Neuron Repair Facts:

• When the cell body of a neuron is destroyed, the axon breaks up into small parts and is later phagocytosed.

• Wallerian degeneration: the degeneration of an axon that has been detached from the remainder of the cell.

• After the axon is transected, changes occur in the cell body; these changes vary according to type of neuron.

• Most neurons with transected axons simply disappear, and some are not significantly altered.

• Regeneration in CNS and PNS differs in terms of axonal regeneration.

• Axonal regrowth in PNS faster than in CNS.

• Neurons and glial cells promote survival of neurons and axonal regrowth.

• Oligodendrocytes and myelin inhibit neurons and axonal regrowth.

• Partial functionality of neurons is restored in CNS using axonal sprouting.

• Neurons don't survive transplantation in CNS. However, neurons transplanted from embryonic tissue to adult brain grow.

Neuroglial Cells:

• Neurons and neuroglia are metabolically interdependent.

• There are four main types: astrocytes, oligodendroglia, ependyma, and microglia.

• When brain and spinal cord are injured, astrocytes near site of injury undergo hypertropy.

Additional Reading:

Basic Neurology

1. Peripheral Nervous System
2. Central Nervous System
3. The Ventricular System
4. The Spinal Cord
5. The Brain Stem
6. The Cerebellum
7. Visual Pathways
8. Diencephalon
9. Basal Ganglia
10. Cerebral Cortex
11. Sleep Disorders
12. Autonomic Nervous System
13. Cranial Nerves and Parasympathetic Ganglia
14. Cells of the Nervous System
15. Cerebrospinal fluid
16. Additional short notes on Cerebrum
17. Functions and Diseases of Cerebrum
18. Subcortical Grey Matter
19. Notes on The Spinal Cord
20. Regulation of Heart Rate by Autonomic Nervous System
21. Action Potentials, Axon Conduction, and Neuromuscular Junction
22. Types of Seizures
23. What is a Cough Reflex?
24. Notes on Congenital Prosopagnosia
25. Findings in Parkinson's Disease
26. Types of Heat Strokes
27. Types of Strokes
28. What is Benign Intracranial Hypertension?
29. What is Cauda Equina Syndrome?
30. Cranial Nerve Locations in Brain Stem
31. What is a Cluster Headache?
32. What is a Subarachnoid Hemorrhage?
33. What is a Tension Headache?

Neurology Videos

1. Video of Neurology Examination in a Clinical Setting

Medical Images

Useful Medical Images & Diagrams (link opens in a new window)

Related Topics

1. Nervous System Disorders
2. Histology of Nervous Tissue
3. Cranial Nerve Reflexes
4. Motor System Examination

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