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Astrocytes are known to facilitate changes in blood flow [7] [8] and have long been thought to play a role in waste removal in the brain. [9] Astrocytes express water channels called aquaporins. [10] Until 2000, no physiological function had been identified that explained their presence in the mammalian CNS.
In a person without hydrocephalus, CSF continuously circulates through the brain, its ventricles and the spinal cord and is continuously drained away into the circulatory system. Alternatively, the condition may result from an overproduction of the CSF, from a congenital malformation blocking normal drainage of the fluid, or from complications ...
It can cause headaches, made worse by standing, moving and coughing, [33] as the low CSF pressure causes the brain to "sag" downwards and put pressure on its lower structures. [33] If a leak is identified, a beta-2 transferrin test of the leaking fluid, when positive, is highly specific and sensitive for the detection for CSF leakage. [ 34 ]
Pneumocephalus is the presence of air or gas within the cranial cavity. It is usually associated with disruption of the skull: after head and facial trauma, tumors of the skull base, after neurosurgery or otorhinolaryngology, and rarely, spontaneously. Pneumocephalus can occur in scuba diving, but is very rare in this context.
Relatively small amounts of regular ice appear white because plenty of air bubbles are present, and also because small quantities of water appear to be colorless. In glaciers, on the other hand, the pressure causes the air bubbles, trapped in the accumulated snow, to be squeezed out increasing the density of the created ice.
Cerebral edema is excess accumulation of fluid in the intracellular or extracellular spaces of the brain. [1] This typically causes impaired nerve function, increased pressure within the skull, and can eventually lead to direct compression of brain tissue and blood vessels. [1]
Scientists have found that the brains of humans and other mammals have a system for choosing which life experiences are important enough to be cemented into long-term memory — and which will be ...
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 because too little pressure could cause brain tissue to become ischemic (having inadequate blood flow), and too much could raise intracranial pressure (ICP).