(Study Material For DNL Students/ other Paramedical Students)
What is Nervous Tissue
Nervous tissue consists of neurons, which transmit nerve impulses, and glial cells, which provide support and protection for neurons. This tissue is concentrated in the central nervous system (brain and spinal cord) and extends throughout the body via the peripheral nervous system. Neurons are specialized for rapid communication, while glial cells maintain homeostasis, form myelin, and provide support and protection.
Nervous tissue is responsible for transmitting electrical signals throughout the body, allowing for communication between different parts of the body and the brain. It processes sensory information, controls and coordinates bodily functions, and enables responses to internal and external stimuli. This tissue is essential for both voluntary and involuntary actions, including thought, emotion, and reflexes.
Types of Nervous Tissue
1. Neurons: These are the primary functional units of the nervous system responsible for transmitting electrical signals throughout the body. Neurons have three main parts: the cell body (soma), dendrites (which receive signals), and the axon (which transmits signals).
2. Neuroglia (Glial Cells): These cells support, protect, and nourish neurons. They outnumber neurons and perform a variety of functions, including maintaining the extracellular environment, forming myelin (which insulates axons), and participating in immune responses within the nervous system. Major types of neuroglia include:
- Astrocytes: Support and maintain the blood-brain barrier, regulate blood flow, and provide metabolic support.
- Oligodendrocytes: Form the myelin sheath around axons in the central nervous system (CNS).
- Microglia: Act as the primary immune cells in the CNS, clearing away debris and pathogens.
- Ependymal Cells: Line the ventricles of the brain and the central canal of the spinal cord, producing and circulating cerebrospinal fluid.