Minerva

The human nervous system contains an estimated one trillion (10¹²) glial cells—they outnumber neurones by 10 to one. Once they were thought of as doing little more than providing a scaffolding to hold nerve networks together. Now it’s becoming clearer that these cells are important in modulating neuronal activity, and astroglial dysfunction may even be involved in neuropsychiatric illness (Journal of Neuropsychiatry and Clinical Neuroscience 2008 20:0iv-129; doi: 10.1176/appi.neuropsych.20.2.iv).

Blood flow to the heart is different from blood flow to other parts of the body. Because ventricular contraction occludes intracardiac blood vessels during systole, flow occurs only in diastole. The driving force derives from stretching of the aortic wall, and as the aorta gets stiffer with age this force gradually lessens and coronary flow reserve decreases. When angina occurs in elderly people without coronary narrowing, says an editorial in Heart (2008;94:690-1; doi: 10.1136/hrt.2007.134791), loss of …