Diseases of the nervous system .. . ^ contains the following elements: (a) Firm tissuewhich largely forms the central nervous s3-stem; (h) Blood; (c) Cerebro-spinal fluid. Of these component parts the tissues undergo a change in vol-ume to the least extent and only after a long time. The amount of blood depends upon the general and local circulation. Inthis respect the most important factor is the height of the blood pressure in. Subar;ichtniiils|>ace Fig. 12; the aorta and vena cava, the caliber of the arteries which enter the cerebro->pinal cavity, of the veins which emerge from it. an
Diseases of the nervous system .. . ^ contains the following elements: (a) Firm tissuewhich largely forms the central nervous s3-stem; (h) Blood; (c) Cerebro-spinal fluid. Of these component parts the tissues undergo a change in vol-ume to the least extent and only after a long time. The amount of blood depends upon the general and local circulation. Inthis respect the most important factor is the height of the blood pressure in. Subar;ichtniiils|>ace Fig. 12; the aorta and vena cava, the caliber of the arteries which enter the cerebro->pinal cavity, of the veins which emerge from it. and the caliber of the cere-Ijral and spinal cord vessels: the latter no doubt varies because of generalconditions and on account of the richness of the muscular coat of the arteriesof the brain. It is immaterial whether vasomotor activity, or the composi-tion of the blood or the hemic requirements of the nervous substance are thedetermining factors. It is obvious that the amount of blood in the centralnervous system and in the cerebrospinal cavity must depend on the caliberand number of the afferent and efferent vessels, and that this is subject togreat and rapid variation, provided there are no other modifying third element in the cavity, the cerebrospinal fluid, serves mainly ascompensation for the first and second. Its amount is adapted to the varia- 226 LUMBAR PUNCTURE tions in volume of the brain substa
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Keywords: ., bookcentury1900, bookdecade1900, bookpu, booksubjectnervoussystem
