How do neurotoxins affect the nervous system?

How does negative feedback regulate the amount of thyroxine in the blood? Why arthritis is more common among older people the the younger ones? How long can one stay to get a period after missing periods for eight months? What possible illness could there be with a sore throat and mucus followed by a rash? What are the symptoms of starvation? Is a neuron an organism? What that means if you are spotting brown before your period but you are not pregnant? Are Teeth the anchored in the maxillary bones and the mandible.? How does dehydration cause headaches? What does an upside down question mark shaped birthmark mean? What type of enzymes would you need to take if the pancreas is removed? How do bats transfer Ebola to humans? Second stage of aerobic respiration? Do people with longer hair get more head lice? Do the teeth bands make your teeth yellow? How do you get rid of a stuffy nose and headache? What part of Titanic sad? What to do when you have a nose bleed? What does Spotting 3 days after conception mean? What happens if you never loose a deciduous tooth?