Search results
Results From The WOW.Com Content Network
Blood flow may increase up to twice the normal flow but no more. If the increased blood flow is sufficient to supply the brain's oxygen needs then no symptoms will result. [6] However, if blood flow cannot be increased or if doubled blood flow does not correct the problem, symptoms of cerebral hypoxia will begin to appear.
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]
Brain trauma or stroke can cause ischemia, in which blood flow is reduced to inadequate levels. Ischemia is followed by accumulation of glutamate and aspartate in the extracellular fluid , causing cell death, which is aggravated by lack of oxygen and glucose .
Global brain ischemia occurs when blood flow to the brain is halted or drastically reduced. This is commonly caused by cardiac arrest. If sufficient circulation is restored within a short period of time, symptoms may be transient. However, if a significant amount of time passes before restoration, brain damage may be permanent.
Cerebral circulation is the movement of blood through a network of cerebral arteries and veins supplying the brain. The rate of cerebral blood flow in an adult human is typically 750 milliliters per minute, or about 15% of cardiac output. Arteries deliver oxygenated blood, glucose and other nutrients to the brain.
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 neurologic signs and symptoms must last longer than 24 hours or the brain infarction is demonstrated, mainly by imaging techniques. [45] Transient ischemic attack (TIA) also called a mini-stroke. This is a condition in which the blood flow to a region of the brain is blocked, but blood flow is quickly restored and the brain tissue can fully ...
Mostly in the frontal cortex, these differences often stem from a smaller brain volume, and the decreased blood flow that results influences the hypofrontality. [9] It has not been determined if the reduction of the frontal cortex is the ultimate cause of the symptoms, or if the condition worsens as the symptoms develop.