Part A: Nervous tissue contains neurons as well as supporting cells. These supporting cells have long processes extending from their cell bodies, which form insulation around the neural processes and protect the delicate neurons within the nervous system.
Within nervous tissue, there are specialized cells called neuroglia, or glial cells, that serve as support cells. These cells do not transmit nerve impulses like neurons do, but they have several critical functions, including:
1. Maintaining homeostasis in the nervous system. 2. Forming the myelin sheath around neuronal axons for insulation. 3. Protecting neurons by acting as a physical barrier and modulating the immune response. 4. Providing nutrients and removing waste from neurons.
The glial cells that form insulation around the axons of neurons in the central nervous system are called oligodendrocytes, while in the peripheral nervous system, these cells are called Schwann cells. The myelin sheath they create is essential for the efficient conduction of nerve impulses. Without this insulation, the speed and efficiency of electrical signal transmission would significantly decrease.
Other glial cells include astrocytes, which contribute to the blood-brain barrier and help regulate the environment around neurons, and microglia, which have immune functions and are involved in cleaning up debris in the nervous system.
The supporting cells mentioned in your statement are likely referring to glial cells, also known as neuroglia. These cells play an essential role in the nervous system by providing structural and metabolic support to neurons. One type of glial cell that forms insulation around neurons is the oligodendrocyte in the central nervous system (CNS) and the Schwann cell in the peripheral nervous system (PNS).
Oligodendrocytes extend their processes to wrap around the axons of neurons in the CNS, creating a fatty layer called myelin. Similarly, Schwann cells wrap around axons in the PNS, also forming a myelin sheath. This myelin sheath serves several functions:
1. Insulation - It prevents the electrical current from leaving the axon and increases the speed of nerve impulse conduction. 2. Protection - The myelin sheath also protects the axon from chemical and physical damage. 3. Nutritional support - Glial cells provide nutrients and other forms of support to neurons, ensuring their health and functionality.
The formation of myelin sheaths by these supporting cells is vital for the proper functioning of the nervous system, as it enables rapid and efficient signal transmission.