To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure firstname.lastname@example.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
The brain has high energy requirements combined with an inability to store substrates critical for this tissue metabolism. This precarious balance results in a vital organ that is highly dependent on constant blood flow, providing oxygen and glucose via tissue perfusion. Although the brain only comprises 2% of total body weight, it receives 15% of cardiac output (700 ml/min) at rest, and accounts for 20% of oxygen consumption, and an even greater proportion of glucose utilization. Even brief interruptions in blood flow can trigger acute cerebral dysfunction, whether loss of consciousness from global hypoperfusion (e.g. syncope from non-perfusing cardiac arrhythmias or hypotension) or focal neurological deficits relating to ischemia from thromboembolism or vasospasm.