1. Comparative Anatomy Circulatory System
Kardong
Chapter 12
Part 13

2. Cardiovascular System
Arteries
Carry blood away from the heart
Muscular, elastic fibrous walls (see next figure)
Regulates blood pressure
Terminate in capillary bed
Veins
Carry blood toward the heart
Heart
Modified blood vessel
Figure Cross section of artery and vein.

3. Arteries, Veins, and Capillaries
Figure Blood vessel microanatomy..

4. Aortic arches- Within pharyngeal arches
Figure Basic circulatory pattern of amniote embryo.

5. Aortic arches- Within pharyngeal arches (discussed later)
Figure Embryological development of aortic arches (see book figures ).

6. Portal Systems
Veins that drain an organ and dump blood into another organ instead of heart
Figure Portal systems of craniates.

7. Portal Systems (cont’d.)
Hepatic
Drains small intestine into liver
Renal
Drains venous channels of tail into kidneys
Hypophyseal
Drains hypothalamus into sinusoids of anterior pituitary
Smallest
Figure Hepatic and renal portal systems of shark (book figure 12.11).

8. Portal Systems (cont’d.)
Figure Hypophyseal portal system
(book figure 15.15) .

9. Heart In a typical tetrapod, the heart pumps blood:
By pulmonary arteries, from heart to lungs (blood returns to heart by pulmonary veins)
By aorta to systemic circulation…
Fish heart – tube-like
4 chambers:
Sinus venosus
Atrium
Ventricle
Conus arteriosus
Figure Four chambers of heart in
most fishes (book figure 12.26).

10. Fish Heart (cont’d.) Fish heart Sinus venosus Atrium Ventricle
Conus arteriosus*
Figure Fish with four chambered heart (book figure 12.27).

11. Fish Heart (cont’d.) Sinus venosus Atrium Thin-walled venous chamber
Receives blood from ducts of Cuvier, coronary veins, hepatic veins
Atrium
Large and thin walled
Dorsal to ventricle

12. Fish Heart (cont’d.) Ventricle
Dumps into conus artriosus- continuous with aorta
Chambers separated by valves: sino-atrial note, sino-ventricular node, semi-lunar valve
Conus arteriosus (bulbus cordis in embryos)
Short in bony fish and amphibians
Termed bulbous arteriosus (if walls lack cardiac muscle, but contains smooth muscle)
Not found in adult amniotes

13. Phylogeny of the Heart Figure 13.11. Heart chambers,
oxygenated blood flow (red),
and septum modification .

14. 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)

15. Spiral Valve
Figure Spiral valve in dipnoans; longitudinal folds of conus lining (book figure 12.29).
Figure Spiral valve in anurans; single flap (book figure 12.30).

16. Amphibian Heart
Spiral valve directs oxygenated blood entering ventricle from left atrium
Conus (termed truncus arteriosus when greatly reduced)
Bulbus arteriosus
Swelling of ventral aorta
Smooth muscle
Figure Three chambered frog heart.

17. Amphibian Heart (cont’d.)
Urodele - partially divided circulation
Right and left atrium
Sinus venosus dumps into right atrium
Pulmonary veins leave left ventricle
Reptile - fully divided circulation
Figure Salamander heart chambers (left) and circulation path (book figures and 12.31).

18. 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

19. Turtle Heart
Figure Chelonian heart chambers and circulation path (see book figure 12.33).

20. Squamate Heart
Figure Squamate heart chambers and circulation path (book figure 12.35).

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 Crocodilian blood circulation when (a) diving and when (b) on the surface.

23. Two Aortic Trunks
Figure Turtle heart and two aortic trunks emerging .
Figure Crocodilian foramen of Panizza connects two aortic trunks at base (see book figure 12.36).

24. Higher 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 Mammalian Heart
Figure Adult heart blood flow (see book figure 12.42).

26. Aortic Arches Basic pattern has 6 aortic arches
Major arterial channels
Ventral aorta
Dorsal aorta
6 pairs of aortic arches
connects ventral aorta
and dorsal aortae
Reptiles - additional arch
Figure Adult heart blood flow (book figure 12.13).

27. Aortic Arches (cont’d.)
Figure Basic pattern of aortic arches and dorsal aortae.
Figure Ventral perspective of aortic arches (book figure 12.19).

28. Figure 13.26. Left aortic arches (see book figure 12.17).

29. Aortic Arches (cont’d.)
Teleost
1st and 2nd arches lost
Dorsal aortae become internal carotids
Lung fish
Pulmonary artery from 6th arch
Tetrapods
5th arch lost
Figure Aortic arches, internal carotids (ic) and pulmonary artery (book figure 12.14).

30. Tetrapod Aortic Arches
1st and 2nd arches lost
Dorsal segment dropped between 3rd and 4th arches
Ductus caroticus
Figure Adult aortic arches (see book figure 12.17).

31. Tetrapod Aortic Arches (cont’d.)
3rd arch extends to internal carotids
Carotid arch
Ventral aorta extension
External carotid
Common carotid at base between 3rd and 4th
Figure Aortic arches, internal carotid (ic), external carotic (ec) and common carotid (cc) (book figure 12.14).

32. Tetrapod Aortic Arches (con’t)
5th arch lost
Dorsal segment of 6th arch lost
4th arch - no anterior connection
Aortic arch (systemic arch)
6th arch
Pulmonary arch
Ex: adult anuran
Figure Adult aortic arches (book figure 14.19).

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

34. Aortic Arch Summary 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
Figure Modifications of aortic arches and their derivative in anamniotes (book figure 12.14).

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 (ligamentum arteriosum)
Figure Adult aortic arches (book figure 12.19).
Figure Left aortic arches (book figure 12.17).

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 Sinus venosus - where all blood returns
Feed by common cardinals and subclavian veins
Shark renal portal system - drains blood from tail before entering post cardinal (book figure 12.21)
Figure Modifications of basic venous patterns showing sinus venosus (S) (book figure 12.21).

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 portal veins - receives blood from intestine into liver
Hepatic veins – direct blood into sinus venosus

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 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 Ventral view of venous channels of rabbit (see book figure 12.23).

44. Fetal Circulation
Figure Circulation of mammalian fetus (see book figure 12.42).

45. Fetal Circulation (cont’d.)
Figure Fetal circulation before birth.

46. Fetal Circulation (cont’d.)
Figure Pre birth fetal circulation: liver (I), inferior vena cava (II), rt. atrium (III), lt. atrium (IV), ductus arteriosus into descending aorta (see book figure 12.42).

47. Fetal Circulation (cont’d.)
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 Foramen ovale in fetal circulation system.

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

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 13.44. Post birth modifications in fetal circulation.