====== Penumbra ======

The cerebral metabolic rate of oxygen consumption ([[CMRO2]]) arises from [[neuron]]s utilizing energy for two functions: 

1) maintenance of cell integrity ([[homeostasis]]) which normally accounts for ≈ 40% of energy consumption, and 2) conduction of electrical impulses. The occlusion of an artery produces a central core of ischemic tissue where the [[CMRO2]] is not met. The oxygen deficiency precludes aerobic [[glycolysis]] and [[oxidative phosphorylation]]. [[ATP]] production declines and cell homeostasis cannot be maintained, and within minutes irreversible cell death occurs; a so-called [[cerebral infarction]]. Surrounding this central core is the [[penumbra]], where collateral flow (usually through [[leptomeningeal vessels]]) provides marginal [[oxygenation]] which may impair cellular function without immediate irreversible damage. Cells in the penumbra may remain viable for hours.

===== Company =====

see [[Penumbra Company]].