| Theme |
Functional and Organic Changes of Brain Observed in Dialysis Patients |
| Title |
Physiology of cerebral blood flow and metabolism |
| Author |
Tetsuhiko Nagao |
2nd Department of Internal Medicine, Kyushu University |
| Author |
Masatoshi Fujishima |
2nd Department of Internal Medicine, Kyushu University |
| [ Summary ] |
Neuronal cells make use of oxygen and glucose in the blood as energy sources. Accordingly, a constant blood supply is essential for the maintenance of normal brain functions. In fact, cerebral blood flow is kept at a constant level despite rapid changes in blood pressure (autoregulation). In contrast to this global control of the cerebral circulation, regional cerebral blood flow shows tight coupling with cerebral metabolism; a local increase in neuronal activity results in an increase in cerebral blood flow in that particular region of the brain. This coupling helps to maintain smooth functioning of the brain with an economical supply of blood to appropriate regions. Cerebral blood flow is modulated by a number of physiological variables; these include pH, carbon dioxide, oxygen, and hematocrit. Some of these variables may mediate the coupling of cerebral blood flow and metabolism. Physiological control is altered under certain diseases conditions and can be modulated by some pharmacological agents. |