Chapter 15 - Section 15.2 - Study Guide - Assess Your Learning Outcomes - Page 575: 2

The sympathetic chain, also known as the sympathetic trunk or sympathetic ganglia, is a paired chain of ganglia that runs along both sides of the vertebral column. It is a crucial component of the sympathetic nervous system, which plays a role in the "fight or flight" response and the regulation of various physiological functions. The anatomy of the sympathetic chain includes ganglia at various levels of the spinal cord, each of which supplies nerve fibers to specific body regions. Here's an overview of the sympathetic chain ganglia and their associated body regions: 1. Cervical Sympathetic Ganglia: - There are three cervical sympathetic ganglia located in the neck region. - These ganglia are referred to as the superior cervical ganglion, middle cervical ganglion, and inferior cervical ganglion. - Nerve fibers from these ganglia innervate structures in the head, neck, and upper thorax. They play a role in regulating functions such as pupil dilation, salivation, and blood vessel constriction in these areas. 2. Thoracic Sympathetic Ganglia: - There are 11 to 12 thoracic sympathetic ganglia corresponding to the thoracic spinal cord segments (T1 to T12). - Nerve fibers from these ganglia supply structures in the thoracic cavity, including the heart, lungs, and esophagus. - These ganglia are involved in regulating heart rate, bronchodilation, and other functions related to the thoracic organs. 3. Lumbar Sympathetic Ganglia: - There are typically four lumbar sympathetic ganglia corresponding to the lumbar spinal cord segments (L1 to L4). - Nerve fibers from these ganglia supply the abdominal organs, pelvic organs, and lower limbs. - They are involved in regulating functions such as blood flow to the abdominal organs and controlling responses in the lower limbs. 4. Sacral Sympathetic Ganglia: - The sacral sympathetic ganglia are situated in the pelvic region and correspond to the sacral spinal cord segments (S1 to S5). - Nerve fibers from these ganglia supply the pelvic organs, including the bladder, reproductive organs, and rectum. - They play a role in controlling functions such as bladder emptying, sexual arousal, and bowel movements. 5. Coccygeal Sympathetic Ganglia: - There may be one or two coccygeal sympathetic ganglia located near the coccyx (tailbone). - Nerve fibers from these ganglia supply the structures in the coccygeal and perineal regions. - They are involved in controlling functions related to the coccyx, anus, and perineum. The sympathetic chain ganglia serve as relay stations where preganglionic fibers from the spinal cord synapse with postganglionic neurons. These postganglionic neurons then distribute sympathetic nerve impulses to their target organs and tissues, allowing for coordinated physiological responses during stress or emergencies.

The sympathetic chain, also known as the sympathetic trunk or sympathetic ganglia, is a paired chain of ganglia that runs along both sides of the vertebral column. It is a crucial component of the sympathetic nervous system, which plays a role in the "fight or flight" response and the regulation of various physiological functions. The anatomy of the sympathetic chain includes ganglia at various levels of the spinal cord, each of which supplies nerve fibers to specific body regions. Here's an overview of the sympathetic chain ganglia and their associated body regions: 1. Cervical Sympathetic Ganglia: - There are three cervical sympathetic ganglia located in the neck region. - These ganglia are referred to as the superior cervical ganglion, middle cervical ganglion, and inferior cervical ganglion. - Nerve fibers from these ganglia innervate structures in the head, neck, and upper thorax. They play a role in regulating functions such as pupil dilation, salivation, and blood vessel constriction in these areas. 2. Thoracic Sympathetic Ganglia: - There are 11 to 12 thoracic sympathetic ganglia corresponding to the thoracic spinal cord segments (T1 to T12). - Nerve fibers from these ganglia supply structures in the thoracic cavity, including the heart, lungs, and esophagus. - These ganglia are involved in regulating heart rate, bronchodilation, and other functions related to the thoracic organs. 3. Lumbar Sympathetic Ganglia: - There are typically four lumbar sympathetic ganglia corresponding to the lumbar spinal cord segments (L1 to L4). - Nerve fibers from these ganglia supply the abdominal organs, pelvic organs, and lower limbs. - They are involved in regulating functions such as blood flow to the abdominal organs and controlling responses in the lower limbs. 4. Sacral Sympathetic Ganglia: - The sacral sympathetic ganglia are situated in the pelvic region and correspond to the sacral spinal cord segments (S1 to S5). - Nerve fibers from these ganglia supply the pelvic organs, including the bladder, reproductive organs, and rectum. - They play a role in controlling functions such as bladder emptying, sexual arousal, and bowel movements. 5. Coccygeal Sympathetic Ganglia: - There may be one or two coccygeal sympathetic ganglia located near the coccyx (tailbone). - Nerve fibers from these ganglia supply the structures in the coccygeal and perineal regions. - They are involved in controlling functions related to the coccyx, anus, and perineum. The sympathetic chain ganglia serve as relay stations where preganglionic fibers from the spinal cord synapse with postganglionic neurons. These postganglionic neurons then distribute sympathetic nerve impulses to their target organs and tissues, allowing for coordinated physiological responses during stress or emergencies.