the.com/circulatory system
Your body's traffic network, delivering oxygen and gossip-level hormones to every cell nonstop.
means The network of heart, blood, and vessels that pumps blood through your body, carrying oxygen, nutrients, hormones, and waste to and from every cell.
from "Circulate" traces to Latin circulatus/circulare, "to form a circle," from circulus, "small ring" — a diminutive of circus. The word originally described anything moving round and returning to its start; physicians and anatomists from the 17th century onward (following the discovery that blood travels in a continuous loop rather than being endlessly made and consumed) borrowed that same image of circling to name the system that keeps blood endlessly looping through the body.
- total length
- blood vessels could circle Earth twice
- daily workload
- heart pumps about 2000 gallons of blood
- speed record
- one blood cell completes full loop in under a minute
- backup design
- capillaries are one cell thick, built for leaking on purpose