This low magnification image shows the wall of the gall bladder pretty well. What might are first be taken as vill really aren't. They're folds in the mucosa, permanent rugations like those in the stomach. They vary in height depending on how full the bladder is. When it's distended the folds are lower than you see them here.
Bile ducts carry bile to the gall bladder for temporary storage.
Though these cells do have a few microvilli on their free surfaces, there is no real brush border. There isn't any muscularis mucosae, and the tunica muscularis is stringy and scanty and shot through with collagen fibers. Since it has only the function of squirting bile into the duct that carries it to the duodenum, it needn't be well-developed.