Using instruction

Hi, i would like to know when we are using the instruction "using like this :

using (var context = new BloggingContext())
{
    var blogs = context.Blogs.ToList();
}

using (var context = new BloggingContext())
{
    var blogs = context.Blogs.ToList();
}

does it automatically dispose all the variable inside "blogs" and "context" ?

Using instruction - C#