Not a circle

123456789101112
Across
  1. 3. arteries and veins
  2. 4. a transporting machine
  3. 6. two fists
  4. 7. always receiving and sending below
  5. 9. don't deviate and don't mix
  6. 11. the strong left chamber
  7. 12. circulating through a system of vessels
Down
  1. 1. to the body via this
  2. 2. much like the controller of one way hallways
  3. 5. the four C's
  4. 8. stuck in the middle with you
  5. 10. sac attack