1. Comparative Anatomy Circulatory 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 Renal Hypophyseal
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 Atrium 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 Conus arteriosus
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 Birds and mammals
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 Lung fish Tetrapods
1st and 2nd arches lost
Dorsal aortae become internal carotids
Lung fish
Pulmonary artery from 6th arch
Tetrapods
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 Reptiles 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.

51. Literature Cited
Figure
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Figure 13.3, 13.4, 13.9, 13.10, 13.11, 13.12, 13.14, 13.17, 13.18, 13.19, 13.21, 13.22, 13.23, 13.24, 13.25, 13.26, 13.28, 13.29, 13.30, 13.31, 13.32, 13.33, & Kent, George C. and Robert K. Carr. Comparative Anatomy of the Vertebrates. 9th ed. McGraw-Hill, 2001.
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