Human anatomy is fascinatingly and frustratingly complex. In each body, 600 muscles, 206 bones, and 360 joints provide structural stability and movement; two lungs circulate air through 1,500 miles of airways to 480,000,000 alveoli with every breath; one heart circulates 5-6 liters of blood through 60,000 miles of vessels every 30 seconds; 600 lymph nodes activate the immune system and filter fore…