What is the Difference Between Sensory and Autonomic Ganglia

The main difference between sensory and autonomic ganglia is that sensory ganglia contain the cell bodies of sensory neurons, whereas autonomic ganglia contain the cell bodies of efferent neurons of the autonomic nervous system.

Sensory and autonomic ganglia are the two types of ganglia of the peripheral nervous system (PNS). Ganglia are nodular masses of cell bodies of the ganglion cells. They occur with their supporting neuroglia called capsule cells. 

Key Areas Covered

1. What are Sensory Ganglia
– Definition, Facts, Features
2. What is Autonomic Ganglia
– Definition, Facts, Features
3. Similarities Between Sensory and Autonomic Ganglia
– Outline of Common Features
4. Difference Between Sensory and Autonomic Ganglia
– Comparison of Key Differences
5. FAQ – Sensory and Autonomic Ganglia
– Answers to frequently asked questions

Key Terms  

Autonomic Ganglia, Sensory Ganglia

What are Sensory Ganglia

Sensory ganglia are a type of ganglia comprising cell bodies of sensory neurons. An example of sensory ganglia is the dorsal root ganglia, clusters of sensory nerve bodies occurring at the base of the spine. They contain somatic sensory and visceral sensory neurons. They respond to mechanical, chemical, and thermal stimuli. Another example of sensory ganglia is the sensory ganglia of the cranial nerves. 

Figure 1: Dorsal Root Ganglion

There are six types of sensory ganglia of cranial nerves.

Trigeminal ganglion: Contains cell bodies of the neurons, which provide sensory innervation to the large part of the head. They are the largest of the cranial nerve ganglia.

Geniculate ganglion: These are ganglions of the facial nerves. They gather sensory information from the tongue, nasal cavity, and outer ear. 

Spiral ganglion: Contain the ganglions of the cochlear branch of the vestibulocochlear nerve.

Vestibular ganglion: Contain ganglions of the vestibular branch of the vestibulocochlear nerve. It occurs in the fundus of the internal auditory meatus.      

Superior and inferior ganglia of the vagus nerve: The vagus nerve contains two ganglia. Their neurons have the dura of the posterior cranial fossa. 

Glossopharyngeal ganglia: Contain the two ganglia of the glossopharyngeal nerve. The superior ganglion contains the cell bodies of neurons, which innervate the middle ear and internal surface of the tympanic membrane.

What are Autonomic Ganglia

Autonomic ganglia are the other type of ganglia. The three main types of autonomic ganglia are the sympathetic chain ganglia, prevertebral ganglia, and parasympathetic or terminal ganglia. 

Figure 2: Autonomic Ganglia

Sympathetic chain ganglia: Another name for sympathetic chain ganglia is paravertebral ganglia. A pair of sympathetic chain ganglia occurs ventrally and laterally in the spinal cord. Likewise, 23 pairs of sympathetic chain ganglia occur in different regions; 3 appear in the cervical region, 12 in the thoracic region, 4 in the lumbar region, and four in the sacral area.

Prevertebral ganglia: Occur between the sympathetic chain ganglia and prevertebral ganglia. The neurons containing prevertebral ganglia innervate all organs of the abdominal and pelvic cavities. 

Parasympathetic ganglia: Belong to the parasympathetic nervous system. They occur between the head, neck, and trunk close to the thoracic, abdominal, and pelvic organs. 

Similarities Between Sensory and Autonomic Ganglia

• Sensory and autonomic ganglia are two ganglia types that occur in the peripheral nervous system.
• They contain cell bodies and their supportive cells.
• They occur outside of the central nervous system. 

Difference Between Sensory and Autonomic Ganglia

Definition

Sensory ganglia refer to the enlargements along peripheral nerves, comprising the soma of sensory neurons. In contrast, autonomic ganglia refer to clusters of neuron cell bodies that transmit sensory signals from the periphery to the integration centers in the CNS.

Examples

Examples of sensory ganglia include dorsal root ganglia and sensory ganglia of the cranial nerves, while autonomic ganglia include sympathetic, prevertebral, and parasympathetic ganglia.

Function

Sensory ganglia respond to mechanical, chemical, and thermal stimuli, while autonomic ganglia conduct impulses to glands and smooth and cardiac muscles. 

FAQ: Sensory and Autonomic Ganglia

What are the two types of ganglia?

Sensory and motor ganglia are the two types of ganglia. Oval cell bodies of the sensory ganglia form a circular pattern. In contrast, motor ganglia form a long chain from the base of the skull down to the tail.  

What are the different types of autonomic ganglia?

Paravertebral (chain) ganglia and prevertebral (collateral) ganglia are the two types of autonomic ganglia. 

Is the spinal ganglion sensory or autonomic?

Sensory ganglia of spinal and cranial nerves and autonomic ganglia are the two types of ganglia. Spinal nerves contain fusiform swellings on each spinal nerve’s posterior root, called sensory ganglia.  

Conclusion

In brief, sensory and autonomic ganglia are two types of ganglia of the peripheral nervous system. Examples of sensory ganglia include the dorsal root and the sensory ganglia of the cranial nerves. They respond to mechanical, chemical, and thermal stimuli. In comparison, examples of autonomic ganglia are sympathetic, prevertebral, and parasympathetic ganglia. They conduct impulses to glands and smooth and cardiac muscles. Therefore, the main difference between sensory and autonomic ganglia is their types and function.            

References:

        1. Molly Smith DipCNM, mBANT. (2023, October 30). Nerve ganglia. Kenhub. 

Image Courtesy:

1. “Spinal Cord Sensory Pathways” By BruceBlaus – Own Work (CC BY SA 4.0) via Anatomy tool
2. “Gray839” By Henry Vandyke Carter – Own Work (Public Domain) via Commons Wikimedia