On your answer-book, write down the name of each of the ganglia marked (i) to (vii) in the diagram below on the parasympathetic and sympathetic divisions of autonomic nervous system :

The autonomic nervous system (ANS) regulates involuntary physiological processes, crucial for maintaining homeostasis. It comprises the sympathetic and parasympathetic divisions, operating largely outside conscious control. These divisions utilize a series of ganglia – clusters of neuronal cell bodies – to relay signals between the central nervous system and target organs. Accurate identification of these ganglia is fundamental to understanding the functional organization of the ANS and its role in coordinating bodily responses. This answer will identify the ganglia marked (i) to (vii) in a standard diagram of the autonomic nervous system, differentiating between sympathetic and parasympathetic components. Assuming a standard diagram depicting the parasympathetic and sympathetic divisions of the autonomic nervous system, the ganglia would be identified as follows: Sympathetic Division Ganglia The sympathetic ganglia are generally located closer to the spinal cord, forming the sympathetic chain ganglia. These ganglia relay preganglionic fibers to postganglionic neurons that then innervate target organs. (i) Cervical Ganglion (Superior Cervical Ganglion): Located in the neck, it innervates the head and upper limbs. (ii) Middle Cervical Ganglion: Part of the sympathetic chain, contributing to innervation of the neck and upper chest. (iii) Thoracic Ganglia: A series of ganglia running along the thoracic vertebrae, innervating the chest and abdomen. (iv) Lumbar Ganglia: Located in the lumbar region of the spinal cord, innervating the lower abdomen and legs. (v) Sacral Ganglia (Inferior Hypogastric Plexus): Located in the sacral region, innervating the pelvic organs. Parasympathetic Division Ganglia Parasympathetic ganglia are typically located closer to or within the target organs, resulting in longer preganglionic fibers and shorter postganglionic fibers. This arrangement allows for more localized and specific control. (vi) Ciliary Ganglion: Located in the orbit, it controls pupillary constriction and accommodation. (vii) Pterygopalatine Ganglion: Located in the facial canal, it innervates the lacrimal, nasal, and palatine glands. It's important to note that the precise location and arrangement of these ganglia can vary slightly between individuals. Furthermore, the sympathetic nervous system also includes prevertebral ganglia (e.g., celiac, superior mesenteric, inferior mesenteric ganglia) which are not necessarily marked in a basic diagram. Division Ganglia Location Function Sympathetic Paravertebral (Cervical, Thoracic, Lumbar, Sacral) “Fight or Flight” response; prepares body for action Parasympathetic Intramural/Near Target Organs (Ciliary, Pterygopalatine) “Rest and Digest” response; conserves energy Accurate identification of autonomic ganglia is crucial for understanding the physiological basis of various bodily functions and the effects of autonomic dysfunction. The sympathetic and parasympathetic divisions, through their distinct ganglion arrangements, orchestrate a complex interplay to maintain internal stability. A thorough understanding of these structures is essential for medical professionals and researchers alike, particularly in the context of diagnosing and treating autonomic disorders.

What is the difference between preganglionic and postganglionic neurons?

Preganglionic neurons originate in the central nervous system and synapse with postganglionic neurons in a ganglion. Postganglionic neurons then extend to the target organ. The sympathetic division typically has shorter preganglionic and longer postganglionic fibers, while the parasympathetic division has longer preganglionic and shorter postganglionic fibers.

Autonomic Nervous System: Ganglia Identification | UPSC Mains ZOOLOGY-PAPER-II 2012

Model Answer

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Introduction

The autonomic nervous system (ANS) regulates involuntary physiological processes, crucial for maintaining homeostasis. It comprises the sympathetic and parasympathetic divisions, operating largely outside conscious control. These divisions utilize a series of ganglia – clusters of neuronal cell bodies – to relay signals between the central nervous system and target organs. Accurate identification of these ganglia is fundamental to understanding the functional organization of the ANS and its role in coordinating bodily responses. This answer will identify the ganglia marked (i) to (vii) in a standard diagram of the autonomic nervous system, differentiating between sympathetic and parasympathetic components.

Assuming a standard diagram depicting the parasympathetic and sympathetic divisions of the autonomic nervous system, the ganglia would be identified as follows:

Sympathetic Division Ganglia

The sympathetic ganglia are generally located closer to the spinal cord, forming the sympathetic chain ganglia. These ganglia relay preganglionic fibers to postganglionic neurons that then innervate target organs.

(i) Cervical Ganglion (Superior Cervical Ganglion): Located in the neck, it innervates the head and upper limbs.
(ii) Middle Cervical Ganglion: Part of the sympathetic chain, contributing to innervation of the neck and upper chest.
(iii) Thoracic Ganglia: A series of ganglia running along the thoracic vertebrae, innervating the chest and abdomen.
(iv) Lumbar Ganglia: Located in the lumbar region of the spinal cord, innervating the lower abdomen and legs.
(v) Sacral Ganglia (Inferior Hypogastric Plexus): Located in the sacral region, innervating the pelvic organs.

Parasympathetic Division Ganglia

Parasympathetic ganglia are typically located closer to or within the target organs, resulting in longer preganglionic fibers and shorter postganglionic fibers. This arrangement allows for more localized and specific control.

(vi) Ciliary Ganglion: Located in the orbit, it controls pupillary constriction and accommodation.
(vii) Pterygopalatine Ganglion: Located in the facial canal, it innervates the lacrimal, nasal, and palatine glands.

It's important to note that the precise location and arrangement of these ganglia can vary slightly between individuals. Furthermore, the sympathetic nervous system also includes prevertebral ganglia (e.g., celiac, superior mesenteric, inferior mesenteric ganglia) which are not necessarily marked in a basic diagram.

Division	Ganglia Location	Function
Sympathetic	Paravertebral (Cervical, Thoracic, Lumbar, Sacral)	“Fight or Flight” response; prepares body for action
Parasympathetic	Intramural/Near Target Organs (Ciliary, Pterygopalatine)	“Rest and Digest” response; conserves energy

Conclusion

Accurate identification of autonomic ganglia is crucial for understanding the physiological basis of various bodily functions and the effects of autonomic dysfunction. The sympathetic and parasympathetic divisions, through their distinct ganglion arrangements, orchestrate a complex interplay to maintain internal stability. A thorough understanding of these structures is essential for medical professionals and researchers alike, particularly in the context of diagnosing and treating autonomic disorders.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

On your answer-book, write down the name of each of the ganglia marked (i) to (vii) in the diagram below on the parasympathetic and sympathetic divisions of autonomic nervous system :

Model Answer

Introduction

Sympathetic Division Ganglia

Parasympathetic Division Ganglia

Conclusion

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Horner's Syndrome

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