CHAPTER XL IV 



Central cardiovascular control 



BORJE UVNAS | Deparlnunl of PImrmacolugy, Karolinska Institittet, Stockholm, Sweden 



CHAPTER CONTENTS 



Efferent Pathways 



Sympathetic Vasoconstrictor Nerves 

 Peripheral distribution 

 Chemical transmission 



Physiologic properties and impulse frequency 

 Sympathetic Vasodilator Nerses 

 Peripheral distribution 

 Skeletal muscles 

 Coronary vessels 

 Skin 



Intestines 

 Chemical transmission 

 Skeletal muscles 

 Coronary vessels 

 Conclusion 

 Physiologic properties and impulse frequency 

 Parasympathetic Vasodilator Ner\es and Cardiac Vagus 

 Peripheral distribution 

 Chemical transmission 

 Physiologic properties 

 Central Representation of Vasoconstrictor and Cardiac Nerves 

 Spinal Cord 



Spinal vasomotor tone 

 Spinal vasomotor reflexes 

 Descending spinal vasomotor pathways 

 Medulla Oblongata 



History and nomenclature 



Location of pressor and depressor regions 



Tonic activity of pressor and depressor regions 



Medullary cardiac centers 



Frequency and rhythmicity of medullary discharge 



McduUospinal vasomotor pathways 



Medullary vasomotor reflexes 



Baroceptors and baroceptive fibers 

 Chemoceptors and chemoceptive fibers 

 Cardiac and pulmonary receptors and afferent fibers 

 Other receptors and afferent fibers 

 Cardiovascular responses 

 Efferent pathways 

 Influence of carbon dioxide and oxygen on spinal and 

 medullary vasomotor neurons 

 Mesencephalon 



Hypothalamus 



Influence on cardiovascular discharge 

 Hypothalamicospinal pathways 

 Cerebral Cortex 

 Motor cortex 

 Frontal lobes 

 Rhinencephalon 

 Temporal lobe 

 Efferent pathways 

 Cerebellum 

 Central Representation of Sympathetic Vasodilator Nerves 

 Medulla Spinalis and Medulla Oblongata 

 Mesencephalon 

 Hypothalamus 

 Cerebral Cortex 



Physiologic Significance of Sympathetic Vasodilator Ner\es 

 Obsolete Vasodilator Center Hypothesis 

 Vasoconstrictor Inhibition and Vasodilator Activation : Two 



Functionally Separate Vasodilator Mechanisms 

 Nervous Control of Venous System 

 Significance of Adrenal Medulla in Cardiovascular Regulation 



THIS SURVEY of ouf knowledge of the central nervous 

 control of the cardiovascular system must necessarily 

 omit discussion of important early works. The author 

 has felt obliged to present his own interpretation of 

 available data since space does not permit lengthy 

 discussion of different points of view. Although electro- 

 physiological data concerning the vasomotor ap- 

 paratus are meager, they will be specially emphasized. 

 In spite of notable advances in techniques for study 

 of the circulatory system and its nervous control since 

 Tigerstedt's (203) manual appeared in 1923, further 

 methodological development is a major need. Nervous 

 control must eventually be described in terms of 

 impulse traffic in afferent and efferent nerve fibers 

 and synaptic routing. Electrophysiological techniques 

 are still of limited value because of the small size of 



1131 



