Nervous tissue, || Nervous tissue histology, || Nervous tissue anatomy and physiology
Nervous Tissue: An Overview
Introduction to Nervous Tissue
- Nervous tissue is one of the four primary types of tissues in the human body, alongside epithelium, connective, and muscle tissues.
- It consists mainly of two components: neurons (nerve cells) and neuroglia (glial cells).
Structure of Neurons
- Neurons have three main parts:
- The cell body, which contains the nucleus and organelles.
- Dendrites that receive incoming signals.
- Axons that transmit signals away from the cell body.
- Axons are often insulated by a myelin sheath, which enhances signal transmission speed.
Role of Neuroglia
- Neuroglia support and protect neurons; they include:
- Astrocytes that maintain the blood-brain barrier and regulate chemical environments around neurons.
- Oligodendrocytes and Schwann cells that produce myelin sheaths.
- Microglia act as immune cells in the central nervous system.
- Ependymal cells help produce cerebrospinal fluid.
Functions of Nervous Tissue
- The primary function is to transmit electrical impulses or nerve signals essential for:
- Sensory perception
- Motor control
- Coordination and communication within the body
- Nervous tissue also contributes to higher cognitive functions such as memory, learning, and decision-making.
Organization of the Nervous System
- The nervous system is divided into two main parts:
- Central nervous system (CNS): includes the brain and spinal cord.
- Peripheral nervous system (PNS): encompasses all other nerves and ganglia.