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Cerebral blood flow (CBF) is the blood supply to the brain in a given period of time. [8] In an adult, CBF is typically 750 millilitres per minute or 15.8 ± 5.7% of the cardiac output. [9] This equates to an average perfusion of 50 to 54 millilitres of blood per 100 grams of brain tissue per minute. [10] [11] [12]
The blood–brain barrier (BBB) is a highly selective semipermeable border of endothelial cells that regulates the transfer of solutes and chemicals between the circulatory system and the central nervous system, thus protecting the brain from harmful or unwanted substances in the blood. [1]
Dicamba is toxic to conifer species but is in general less toxic to grasses. [2] Dicamba is a synthetic auxin that functions by increasing plant growth rate, leading to senescence and cell death. [2] [11] The growth regulating properties of dicamba were first discovered by Zimmerman and Hitchcock in 1942. [12]
Immediately following the event, blood flow and therefore oxygen transport is reduced locally, leading to hypoxia of the cells near the location of the original insult. This can lead to hypoxic cell death ( infarction ) and amplify the original damage from the ischemia ; however, the penumbra area may remain viable for several hours after an ...
The brain is supplied with blood by the internal carotid arteries and also by the posterior cerebral arteries; the posterior communicating arteries connects the two systems. This provides redundancies or collaterals in the cerebral circulation so that, if one system is blocked or narrowed, the other can take over.
Brain ischemia has been linked to a variety of diseases or abnormalities. Individuals with sickle cell anemia, compressed blood vessels, ventricular tachycardia, plaque buildup in the arteries, blood clots, extremely low blood pressure as a result of heart attack, and congenital heart defects have a higher predisposition to brain ischemia in comparison to the average population.
As the brain requires nutrient entry and waste removal, it is perfused by blood flow. Blood can carry a number of ingested toxins, however, which would induce significant neuron death if they reach nervous tissue. Thus, protective cells termed astrocytes surround the capillaries in the brain and absorb nutrients from the blood and subsequently ...
Hypofrontality is a symptom of numerous neurological diseases defined as reduced utilization of glucose and blood flow in the prefrontal cortex. Hypofrontality can be difficult to detect under resting conditions, but under cognitive challenges, it has been seen to correlate with memory deficits along with executive function deficits.