呼吸器系のしくみのホワイトボードアニメーション

Hand-drawn diagram of the human respiratory system inside a simple pale outline of a child's head, neck and chest, the head turned to the side as a cut-away so the air path shows: the nasal cavity behind the nose and the mouth both open into the throat. From the throat the windpipe (trachea) runs straight down the neck with ring-shaped ridges, then splits into exactly two bronchi, one going into each lung, branching into thin tubes inside. Two large pink spongy lungs. Under the lungs, one thin red muscle sheet, the diaphragm, shaped like a dome that bulges UPWARD into the chest like an upside-down bowl, and the bottoms of both lungs curve to rest on top of the dome. No heart, no ribs, no other organs. Nothing else in the picture, plenty of empty space around the body. Coloured pencil and watercolour marker, clean black ink outlines, warm off-white paper, no text.