ภาพประกอบกายวิภาคหัวใจบนกระดานดำวินเทจ

A detailed, vintage-style chalkboard illustration explaining the anatomy of [the human heart]. Realistic, scientific diagram drawn with white and colored chalk on a textured dark slate blackboard. Anatomical parts including ventricles, atria, and valves are labeled with elegant cursive handwriting, featuring fine chalk dust and authentic smudge textures.