Comparative Anatomy Circulatory System

1. Comparative AnatomyCirculatory System Note Set 10 Chapter 12

2. Circulatory System • Aortic arches- within pharyngeal arches • Arteries • Carries blood away from heart • Muscular, elastic fibrous walls • Regulates blood pressure • Terminate in capillary bed • Veins • Carry blood toward heart • Heart • Modified blood vessel Figure 13.1: Cross section of artery and vein.

3. Figure 13.2: Basic circulatory pattern of amniote embryo.

4. Figure 13.3: Embryological development of aortic arches.

5. Portal Systems • Veins drain organ and dump blood into other organ instead of heart Figure 13.4: Portal systems.

6. Portal Systems (cont.) • Hepatic • Drains intestine into liver • Renal • Drains venous channels of tail into kidneys • Hypophyseal • Drains hypothalamus into sinusoids of anterior pituitary • Smallest Figure 13.5: Hepatic and renal portal systems.

7. Portal Systems (cont.) Figure 13.6: Hypophyseal portal system.

8. Heart • Typical tetrapod blood pumped • By pulmonary arteries, from heart to lungs • By pulmonary veins, back to heart

9. Heart (cont.) Figure 13.7: Chambers of the primitive vertebrate heart.

10. Heart (cont.) Figure 13.8: The heart tube elongates and bends.

11. Fish Heart • Fish heart- tube like • 4 chambers: • Sinus venosus • Atrium • Ventricle • Conus arteriosus Figure 13.9: Four chambered heart.

12. Fish Heart (cont.) • Sinus venosus • Thin walled venous chamber • Receives blood from: duct of Cuvier, coronary veins, hepatic veins • Atrium • Large and thin walled • Dorsal to ventricle

13. Fish Heart (cont.) • Ventricle • Dumps into conus artriosus- continuous with aorta • Chambers separated by valves: sino-atrial note, sino-ventricular node, semi-lunar valve • Conus arteriosus • Short in bony fish and amphibians • Not found in adult amniotes

14. Heart Figure 13.10: Heart chambers, oxygenated blood flow (red), and septum modification.

15. Lungfish and Amphibian vs Dogfish • Modifications of partial or complete partition in atrium • Left and right atria • Advent of lungs • Double circulation • Modification in conus arteriosus • Semi-lunar valve modified to shunt deoxygenated blood to lungs (spiral valve)

16. Spiral Valve Figure 13.11: Spiral valve in dipnoans; longitudinal folds of conus lining. Figure 13.12: Spiral valve in anurans; single flap.

17. Amphibian Heart • Spiral valve directs oxy. blood entering ventricle from left atrium • Conus (truncus) arteriosus; also called bulbous cordis • Bulbous arteriosus • Swelling of ventral aorta • Smooth muscle Figure 13.13: Three-chambered frog heart.

18. Amphibian Heart (cont.) • Urodele- partially divided circulation • Right and left atrium • Sinus venosus dumps into right atrium • Pulmonary veins leave left ventricle • Reptile - fully divided circulation, but additional chamber (as in turtle) Figure 13.14: Turtle heart chambers and circulation path.

19. Reptile Heart • Cavum venosum (CV)- internal pocket; e.g., turtle • Blood collected from post cava through sinus venosus to precava • To right atrium • Venous blood to CV • Cavum pulmonale • Into pulmonary artery to lungs • Oxy. blood returns through pulmonary veins in left atrium • Back to CV • To left and right aortic trunk

20. Blood Circulation Figure 13.15: Single loop fish and double loop amphibian and mammal circulation.

21. Crocodilian Heart • Mechanism for breathing and diving • Lungs not utilized • Blood not pumped to lungs • Foramen of Panizza • Valve between aortic trunks to divert blood • Allows left ventricle to pump to both arches when right ventricle closed • Underwater right ventricle helps pump systemic blood

22. Diving • Semilunar valve in right aorta closed when above water • Semilunar valve forced open when submerged in water to divert pulmonary circulation (b) (a) Figure 13.16: Crocodilian blood circulation when (a) diving and when (b) on the surface.

23. Two Aortic Trunks Figure 13.17: Turtle heart and two aortic trunks emerging. Figure 13.18: Crocodilian foramen of Panizza connects two aortic trunks at base.

24. Amniote Heart • 4 chambered heart • 2 atria and 2 ventricles • Birds and mammals • Sinus venosus- 5th chamber in reptile heart • Becomes sino-atrial node • In embryo, right and left atria are not separated • Foramen ovale • Fossa ovalis • Auricle - flap on side of atrium

25. Adult Heart Figure 13.19: Adult heart blood flow.

26. Aortic Arches • Basic pattern has 6 aortic arches • Major arterial channels • Ventral aorta • Dorsal aorta • 6 pairs of aortic arches connects ventral and dorsal aorta • Reptiles - additional aortic trunk

27. Aortic Arches (cont.) Figure 13.20: Basic pattern of aortic arches and dorsal aortae. Figure 13.21: Ventral perspective of aortic arches.

28. Figure 13.22: Left aortic arches.

29. Aortic Arches (cont.) • Teleost • 1st and 2nd arches lost • Dorsal aortae become internal carotids • Lung fish • Pulmonary artery from 6th arch • Tetrapods • Pulmonary artery from 6th arch • 5th arch lost Figure 13.23: Aortic arches, internal carotids (ic) and pulmonary artery.

30. Tetrapod Aortic Arches • 1st and 2nd arches lost • Dorsal segment dropped between 3rd and 4th arches • Ductus caroticus Figure 13.24: Adult aortic arches (book figure 14.19).

31. Tetrapod Aortic Arches (cont.) • 3rd arch extends to internal carotids • Carotid arch • Ventral aorta extension • External carotid • Common carotid at base between 3rd and 4th Figure 13.25: Aortic arches, internal carotid (ic), external carotid (ec) and common carotid (cc).

32. Tetrapod Aortic Arches (cont.) • 5th arch lost • Dorsal segment of 6th arch lost • 4th arch- no anterior connection • Aortic arch • 6th arch • Pulmonary arch • Ex: adult anuran Figure 13.26: Adult aortic arches.

33. Figure 13.27: Modifications of aortic arches and dorsal aortae into mature vascular system.

34. Aortic Arches • Urodele • Ductus caroticus • Ductus arteriosus- dorsal segment of 6th arch • Reptiles • 1st and 2nd arches lost • Ductus caroticus lost • 5th arch lost • Ductus arteriosus lost • Additional aortic arch introduced • Arch from left side loops right • Arch from right side loops left

35. Mammalian Aortic Arches • 3rd, 4th, 5th, & 6th retained embryonically • Adults- 1st and 2nd dropped • 3rd carotid arch • 4th systemic arch • 5th lost • Dorsal segment of 6th lost • Retained embryonically- ductus arteriosus (becomes ligamentum arteriosum) Figure 13.28: Adult aortic arches. Figure 13.29: Left aortic arches.

36. Bird Aortic Arches • Right portion of aortic arch is retained and left is lost (opposite to mammals) • Birds have right aortic arch • Mammals have left aortic arch

37. Venous System • Shark renal portal system- drains • blood from tail before entering post cardinal • Sinus venosus- where all blood returns • Duct of Cuvier or Common Cardinal--Cuvier was a foremost French comparative anatomist • 2 ducts of Cuvier (or derivatives) in most vertebrates Figure 13.30: Modifications of basic venous patterns showing sinus venosus (S).

38. Venus System • Major venous channels • Cardinals: anterior, posterior, common • Renal portal • Lateral abdominals • Vitellines- associated with hepatic portal system • Coronary veins • Additional characteristics of higher vertebrates • Pulmonary • Posterior vena cava

39. Venus System • Common Cardinals- directs blood to sinus venosus • Anterior Cardinals- receives blood from head • Post Cardinals- receives blood from kidneys • Renal Portal- receives blood from caudal vein • Lateral Abdominals- receives blood from abdominal stream to iliac (lateral wall of body) • Hepatic Veins- receives blood from intestine into liver

40. Modifications to Basic Venous System • Post cardinal lost in adult anurans • Post cava- new vessel • Post cava drains kidneys in turtle • External iliac vein connects lateral abdominals and renal portal system

41. Modifications to Basic Venous System • Most mammals lose renal portal system • Pre-cava- common cardinals in higher verts • Internal jugular- anterior cardinal veins • Anterior vena cava- only right pre-cava retained

42. Modifications to Basic Venous System • Azygous- vestige of right post cardinal veins • Hemiazygous- remnant of left post cardinal • Inferior vena cava- post cava (a) (b) Figure 13.31: Ventral view of anterior venous channels of cat and human (a) and ventral view of azygos of rhesus monkey (b).

43. Azygos and Hemiazygos Figure 13.32: Ventral view of venous channels of rabbit.

44. Fetal Circulation Figure 13.33: Circulation of mammalian fetus.

45. Fetal Circulation (cont.) Figure 13.34: Fetal circulation before birth.

46. Fetal Circulation (cont.) Figure 13.35: Pre birth fetal circulation: liver (I), inferior vena cava (II), rt. atrium (III), lt. atrium (IV), ductus arteriosus into descending aorta.

47. Fetal Circulation (cont.) • Oxygenation at placenta • Umbilical veins supply fetus with oxy. blood • Vein passes through liver and unites with post cava • From right atrium, oxy. blood goes 2 directions • To right ventricle • To left atrium through foramen ovale Figure 13.36: Foramen ovale in fetal circulation system.

48. Fetal Circulation (cont.) • In right ventricle, oxy. blood sent to pulmonary artery • Lungs nonfunctional • Ductus arteriosus diverts blood from lungs Figure 13.38: Left aortic arches with ductus arteriosus. Figure 13.37: Adult aortic arches of mammal.

49. Circulation At Birth • Placenta shuts down • Umbilical vein collapses- near falciform ligament • Interatrial aperture closes (fossa ovalis) • Ductus arteriosus closes (ligamentum arteriosum) • Deoxygenated blood now enters right ventricle, pulmonary arteries, and continues to lungs • Ductus venosus collapses (ligamentum venosum)

50. Figure 13.39: Post birth modifications in fetal circulation.