Fig. 19.1. Spleen.

Fig. 19.2. Conducting system of mammalian heart.

Fig. 19.3. Structure of blood vessels.

Table 19-1 Blood Vessels in the Mesenteric Vascular Bed of an Adult Dog

Diameter(mm)

NumberofVessels

Total Cross-sectional Area

(mm2)

Circumferenceof IndividualVessels (mm)

TotalCircumference

(mm)

Aorta 10.0 1 78.5 31.4 31.4Capillaries 0.008 1 billion 60,319.0 0.025 30,159,289.0Vena cava 12.5 1 122.7 39.3 39.3

Dimensions and number of vessels from A. C. Burton.

Fig. 19.4. Aspects of the development of vertebrate circulatory systems.

Fig. 19.5. Development of hepatic portal system of mammals.

Fig. 19.6. Sagittal section through heart of Squalus.

Fig. 19.7. Blood vessels of an elasmobranch.

Fig. 19.7. Gill arches of an elasmobranch.

Fig. 19.8. Hemal arch of a teleost.

Fig. 19.9. Aortic arches and circ-ulation of Africanlungfish.

Fig. 19.10. Aortic arches of lissamphibians.

Fig. 19.11. Ventral dissection of a frog heart

Fig. 19.12. Heart and aorticarches of a turtle or “lizard”

Fig. 19.13. Turtle and crocodilianhearts compared.

Fig. 19.14. Aortic arches of birds and mammals compared.

Fig. 19.15. Development of human aortic arches.

Fig. 19.16. Changes in mammaliancirculation at birth.

Focus 19.1. Evolutionof gill arch circulation and aortic arches.

Fig. 19.17. Comparative anatomyof the venous system in the trunk.

Fig. 19.18. Developmentof the vena cava of Mammals.

Fig. 19.19. Internal and external jugular veins evolved from Anterior cardinal and inferior jugular veins.

Fig. 19.20. Lymphatic system.

Fig. 19.21. Lymphnode.