Parasympathetic Sympathetic Eye Eye Brain stem Salivary glands Skin* Figure 20.1 Overview of the subdivisions of the autonomic nervous system. Parasympathetic Sympathetic Eye Eye Brain stem Salivary glands Skin* Cranial Salivary glands Sympathetic ganglia Heart Cervical Lungs Lungs Heart T1 Stomach Stomach Small intestine Thoracic Pancreas and small intestine Pancreas Liver and gall- bladder Liver and gall- bladder L1 Adrenal gland Lumbar Large intestine Large intestine Bladder Bladder Genitals Sacral Genitals

Figure 20.2 Sympathetic trunks and pathways. Lateral horn (visceral motor zone) Dorsal root Spinal cord Dorsal root ganglion Dorsal root ganglion Dorsal ramus of spinal nerve Ventral root Ventral ramus of spinal nerve Rib Gray ramus communicans Ventral root Sympathetic trunk ganglion Sympathetic trunk ganglion White ramus communicans Sympathetic trunk Sympathetic trunk 1 Synapse at the same level Ventral ramus of spinal nerve Gray ramus communicans White ramus communicans Thoracic splanchnic nerves Location of the sympathetic trunk 2 Synapse at a higher or lower level Skin (arrector pili muscles and sweat glands) Effectors Blood vessels Splanchnic nerve Collateral ganglion (such as the celiac) Abdominal organs (e.g., intestine) Synapse in a distant collateral ganglion anterior to the vertebral column 3 Three pathways of a sympathetic innervation 2