Watch this video to understand the cause and effect of strokes. Pay special attention to the discussion regarding how a stroke harms a person. Because brain cells need blood to supply oxygen and nutrients and to remove waste products, when brain cells are deprived of oxygen – as happens during a stroke – they cannot function properly. In addition, as you review the physical impacts of a stroke, think about how survivors of stroke experience many changes resulting from their illness. Most people are aware of the physical changes that occur following stroke, for example paralysis or weakness on one side of the body, or difficulty with speech and language comprehension. However many people also experience some changes in their mood. For some these changes last for a short time, yet others may have ongoing problems.