1.      

1 umbilical vein

29.             

interventricular sulcus 
(groove)

2.      

2 capillary beds in series

30.             

ligamentum arteriosum

3.      

2 to 3 cells thick

31.             

ligamentum teres 
(round ligament)

4.      

2 umbilical arteries

32.             

lumen

5.      

40 cells thick

33.             

mixed blood

6.      

aorta

34.             

oxygen deficient blood

7.      

arteries

35.             

oxygen rich blood

8.      

arteries away from heart chambers (a a)

36.             

patent ductus arteriosus

9.      

arteriole to arteriole anastomoses

37.             

placenta

10.             

arterioles

38.             

portal circulation

11.             

atrioventricular sulcus (groove)

39.             

pulmonary bypass

12.             

blood

40.             

pulmonary circulation

13.             

bulk flow

41.             

pulmonary trunk 
(aorta, artery)

14.             

capillaries

42.             

right ventricle to 
left atrium

15.             

closed system

43.             

semilunar valves

16.             

collateral circulation

44.             

skeletal muscle pump

17.             

coronary arteries

45.             

systemic circulation

18.             

coronary circulation

46.             

tunica adventitia

19.             

coronary sinus

47.             

tunica externa

20.             

coronary sulcus

48.             

tunica intima

21.             

coronary veins

49.             

tunica media

22.             

diffusion

50.             

urinary bladder

23.             

ductus arteriosus

51.             

varicose veins

24.             

elastic and white fibrous tissue layer

52.             

vasa vasorum

25.             

fetal circulation

53.             

veins

26.             

foramen ovale

54.             

venules

27.             

fossa ovalis

55.             

vessels

28.             

heart