. Biology; the story of living things. 354 THE MAINTENANCE OF THE INDIVIDUAL following braticlios : (]) a dorsal branch; (2) a nioro prominent ventral branch, whicli supplies the skin and body nuisculaturc ; (,S) a com- municating branch, going to the ganglia of the autonomic system and thence to the viscera; and (4) a small meningeal branch, going back to the protective layers of the cord. Thus the nerves emanating from this point of fusion are mixed in character while their roots are not. mesonterii ganglion cfcrsol raot ganglion^ dorsal root Ventral root rocmrcs Communi-. \ ; visntroli?
. Biology; the story of living things. 354 THE MAINTENANCE OF THE INDIVIDUAL following braticlios : (]) a dorsal branch; (2) a nioro prominent ventral branch, whicli supplies the skin and body nuisculaturc ; (,S) a com- municating branch, going to the ganglia of the autonomic system and thence to the viscera; and (4) a small meningeal branch, going back to the protective layers of the cord. Thus the nerves emanating from this point of fusion are mixed in character while their roots are not. mesonterii ganglion cfcrsol raot ganglion^ dorsal root Ventral root rocmrcs Communi-. \ ; visntroli? Components of a spinal nerve. Somatic motor fibers are indicated by solid lines; \ isceral motor by lonp dashes; somatic sen- sory in short dashes; \ isceral sensory by dotted lines. The Autonomic Nervous System The term autonomic nervous system embraces all nerves and ganglia located outside of the spinal cord, which reg- ulate the activities of smooth, or involuntary, muscle and various glands. It should also be thought of as an auxiliary, or perhaps more properly a relay apparatus to supplement the work of the central nervous system. Anatomically the system consists of two ''longitudinally con- nected" chains of ganglia lying on either side and just ventral to the cerebrospinal cord together with various ganglia scattered throughout the viscera and groups of connecting nerves extending to the central nervous system. This system is divisible into two parts. The first is called the thoracicolumbar jiart, and consists of the double chain of ganglia mentioned above together with the connections through the spinal nerves. It reaches the blood vessels, heart, digestive tract, and many other parts of the body. The second, or parasympathetic part, is characterized by having three centers, two cranial centers, one in the mid-brain, one in the medulla region, and a posterior center in the sacral region. Masses of nervous tissue are scattered as ganglia which are located in vario
Size: 1385px × 1804px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorwalterherberteugeneb1867, bookcentury1900, bookpublish
