Blood sugar regulation cells in the pancreatic islets are among the most well understood and important. If the blood glucose level falls to dangerous levels (as during very heavy exercise or lack of food for extended periods), the alpha cells of the pancreas release glucagon, a hormone whose effects on liver cells act to increase blood glucose levels. They convert glycogen into glucose (this process is called glycogenolysis). The glucose is released into the bloodstream, increasing blood sugar. Hypoglycemia, the state of having low blood sugar, is treated by restoring the blood glucose level to normal by the ingestion or administration of dextrose
Blood lead level circulation, lead readily enters the developing brain through the immature blood–brain barrier". "Lead is associated with a wide range of toxicity in children across a very broad band of exposures, down to the lowest blood lead concentrations yet studied, both in animals and people. These toxic effects extend from acute, clinically obvious, symptomatic poisoning at high levels of exposure down to subclinical (but still very damaging) effects at lower levels. Lead poisoning can affect virtually every organ system in the body. The principal organs affected are the central and peripheral nervous system and the cardiovascular, gastrointestinal, renal, endocrine, immune and