B fiber

B fiber is a type of nerve fiber that is part of the autonomic nervous system. These fibers are characterized by their small diameter and low conduction velocity, which is slower than that of A fibers but faster than C fibers. B fibers are myelinated, meaning they are covered by a layer of myelin, a fatty substance that helps to speed up the transmission of nerve impulses.

Structure and Function

B fibers are small, myelinated nerve fibers with a diameter of about 3 micrometers and a conduction velocity of 3 to 15 meters per second. They are part of the autonomic nervous system, which controls involuntary functions such as heart rate, digestion, and breathing. B fibers carry preganglionic autonomic signals from the central nervous system to the autonomic ganglia.

Classification

B fibers can be further classified into two types: preganglionic fibers and postganglionic fibers. Preganglionic fibers originate in the brain or spinal cord and terminate in the autonomic ganglia, while postganglionic fibers originate in the ganglia and terminate in the target organ.

Clinical Significance

Damage to B fibers can result in a variety of neurological disorders, including autonomic neuropathy, a condition characterized by damage to the nerves that control the body's involuntary functions. Symptoms can include problems with heart rate and blood pressure, digestive issues, and difficulty with bladder control.

See Also

• A fiber
• C fiber
• Nerve conduction velocity
• Autonomic nervous system
• Neurological disorder