Overview
This lecture introduces the main types of neural cells in the nervous system, focusing on neurons and glial cells, their locations, origins, and structural features.
Main Categories of Neural Cells
- Neural cells are cells of the nervous system.
- Two main types of neural cells: neurons (nerve cells) and glia (neuroglia or glial cells).
- Neurons process and transmit information; glia support neurons in various ways.
Nervous System Structure
- The nervous system is divided into the central nervous system (CNS: brain and spinal cord) and the peripheral nervous system (PNS: nerves throughout the body).
- Neurons are found in both CNS and PNS.
- Different types of glial cells are found specifically in either CNS or PNS.
Origins of Neural Cells
- Most neural cells develop from neural stem cells or neural crest cells during embryonic development.
- CNS neurons and glia are mainly derived from neural stem cells in the ectoderm.
- PNS neurons and glia are mainly derived from neural crest cells in the ectoderm.
Structure of Neural Cells
- Most neurons and glia have a soma (cell body) containing the nucleus and organelles.
- Neural cells have processes (long, thin extensions) extending from the soma.
- Processes vary in number, length, thickness, branching, terminal structures, and function.
Distribution and Abundance
- There are billions of neurons forming trillions of connections in the adult human nervous system.
- Glial cells outnumber neurons.
Types of Glial Cells (Preview)
- Common glial types to be covered: astrocytes, microglia, ependymal cells, oligodendrocytes, and Schwann cells.
- Less common glial cells include satellite cells and olfactory ensheathing cells.
Key Terms & Definitions
- Neural — related to the nervous system.
- Neuron — a cell that processes and transmits information in the nervous system.
- Glia (Neuroglia/Glial cell) — supportive cells in the nervous system.
- Central Nervous System (CNS) — brain and spinal cord.
- Peripheral Nervous System (PNS) — nerves outside the CNS, throughout the body.
- Soma (Cell Body) — the main part of a neural cell containing the nucleus.
- Processes — extensions from the soma, such as axons or dendrites.
- Neural Stem Cell — embryonic cell giving rise to CNS neurons and glia.
- Neural Crest Cell — embryonic cell giving rise to PNS neurons and glia.
Action Items / Next Steps
- Prepare to learn about the most common types of glial cells in upcoming lectures.