General visceral efferent fibers

General Visceral Efferent Fibers

General visceral efferent fibers, also known as GVE fibers, are a type of nerve fibers that are responsible for carrying motor signals from the central nervous system (CNS) to the smooth muscles, cardiac muscles, and glands of the body. These fibers are part of the autonomic nervous system (ANS), which controls involuntary bodily functions.

Anatomy

General visceral efferent fibers originate from the preganglionic neurons located in the intermediolateral cell column of the spinal cord's lateral horn in the thoracic and upper lumbar regions. These preganglionic neurons are part of the sympathetic division of the ANS.

From the spinal cord, the preganglionic fibers exit through the ventral roots and form synapses with postganglionic neurons in the sympathetic ganglia located in the sympathetic chain. The postganglionic fibers then travel to their target organs, where they innervate smooth muscles, cardiac muscles, and glands.

Function

The main function of general visceral efferent fibers is to regulate the activity of smooth muscles, cardiac muscles, and glands. These fibers control various involuntary processes such as digestion, heart rate, blood pressure, and glandular secretions.

For example, general visceral efferent fibers innervate the smooth muscles of the gastrointestinal tract, allowing for peristalsis and the movement of food through the digestive system. They also innervate the cardiac muscles, regulating the heart rate and ensuring proper blood circulation.

Furthermore, these fibers control the secretion of various glands, including salivary glands, sweat glands, and lacrimal glands. They regulate the production and release of saliva, sweat, and tears, respectively.

Clinical Significance

Disorders or damage to general visceral efferent fibers can lead to dysfunction in the organs they innervate. For example, damage to the fibers innervating the gastrointestinal tract can result in digestive problems such as constipation or diarrhea. Dysfunction of the fibers innervating the heart can lead to irregular heart rhythms or cardiovascular issues.

Understanding the anatomy and function of general visceral efferent fibers is crucial in diagnosing and treating various medical conditions related to the autonomic nervous system. Medical professionals, such as neurologists and gastroenterologists, rely on this knowledge to provide appropriate care to patients.

Related Topics

• Autonomic Nervous System: Provides an overview of the autonomic nervous system, including its divisions and functions.
• Sympathetic Nervous System: Explores the sympathetic division of the autonomic nervous system, to which general visceral efferent fibers belong.
• Smooth Muscles: Discusses the characteristics and functions of smooth muscles, which are innervated by general visceral efferent fibers.
• Cardiac Muscles: Provides information on cardiac muscles and their regulation by general visceral efferent fibers.
• Glands: Explores the different types of glands and their innervation by general visceral efferent fibers.

References

1. Guyton, A. C., & Hall, J. E. (2006). Textbook of medical physiology. Philadelphia, PA: Elsevier Saunders. 2. Standring, S. (Ed.). (2016). Gray's anatomy: The anatomical basis of clinical practice. London, UK: Elsevier.