531x531pxhuman heart anatomy, circulatory system diagram, medical illustration, human biology study, cardiovascular health, anatomical structures, physiological functions
1250x2083pxhuman circulatory system diagram, blood vessel network illustration, human anatomy chart, cardiovascular system overview, human body medical illustration, physiological system depiction, organ function visualization
600x600pxendocrine system diagram, adrenal gland function, human anatomy illustration, releasing and inhibiting hormones, endocrine gland structure, human body physiology, glandular secretion process
