Circulation of blood in the Neurocranium

In the 22nd century, scientists and doctors of mental disturbance have learnt to study the circulation of blood in the body and in the neurocranium. In human anatomy, the neurocranium, also known as the braincase, brainpan, or brain-pan is the upper and back part of the skull, which forms a protective case around the brain. In the human skull, the neurocranium includes the calvaria or skullcap. The remainder of the skull is the facial skeleton.

Cerebral blood flow (CBF) is the blood supply to the brain in a given period of time.^[1] In an adult, CBF is typically 750 millilitres per minute or 15% of the cardiac output. This equates to an average perfusion of 50 to 54 millilitres of blood per 100 grams of brain tissue per minute.^[2][3][4] CBF is tightly regulated to meet the brain’s metabolic demands.^[2][5] Too much blood (a clinical condition of a normal homeostatic response of hyperemia)^[6] can raise intracranial pressure (ICP), which can compress and damage delicate brain tissue. 

 Small alterations in respiration pattern can cause significant changes in global CBF, specially through PaCO2 variations.

Role of intracranial pressure[edit]

Increased intracranial pressure (ICP) causes decreased blood perfusion of brain cells by mainly two mechanisms:

• Increased ICP constitutes an increased interstitial hydrostatic pressure that, in turn, causes a decreased driving force for capillary filtration from intracerebral blood vessels.
• Increased ICP compresses cerebral arteries, causing increased cerebrovascular resistance (CVR).

Cerebral perfusion pressure[edit]

Main article: Cerebral perfusion pressure

Cerebral perfusion pressure, or CPP, is the net pressure gradient causing cerebral blood flow to the brain (brain perfusion). It must be maintained within narrow limits; too little pressure could cause brain tissue to become ischemic (having inadequate blood flow), and too much could raise intracranial pressure(ICP).

 Small alterations in respiration pattern can cause significant changes in global CBF, specially through PaCO2 variations.

This is why doctors should check the respiration rate, depth and pattern at rest, not only for the sake of checking the lungs, but also to check out the ventilatory system apparatus, the circulation and the content of the blood and to check the blood flow to the brain, especially in the case of a patient who has become behaviorally disturbed, distressed and disabled.