Comparative Anatomy Circulatory System Kardong Chapter 12 Part 13

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 13.1. Cross section of artery and vein.

Arteries, Veins, and Capillaries Figure 13.2. Blood vessel microanatomy..

Aortic arches- Within pharyngeal arches Figure 13.3. Basic circulatory pattern of amniote embryo.

Aortic arches- Within pharyngeal arches (discussed later) Figure 13.4-5. Embryological development of aortic arches (see book figures 12.9 -10).

Portal Systems Veins that drain an organ and dump blood into another organ instead of heart Figure 13.6. Portal systems of craniates.

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 13.7. Hepatic and renal portal systems of shark (book figure 12.11).

Portal Systems (cont’d.) Figure 13.8. Hypophyseal portal system (book figure 15.15) .

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 13.9. Four chambers of heart in most fishes (book figure 12.26).

Fish Heart (cont’d.) Fish heart Sinus venosus Atrium Ventricle Conus arteriosus* Figure 13.10. Fish with four chambered heart (book figure 12.27).

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

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

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

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)

Spiral Valve Figure 13.12. Spiral valve in dipnoans; longitudinal folds of conus lining (book figure 12.29). Figure 13.13. Spiral valve in anurans; single flap (book figure 12.30).

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 13.14. Three chambered frog heart.

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 13.15-16. Salamander heart chambers (left) and circulation path (book figures 12.16 and 12.31).

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

Turtle Heart Figure 13.17. Chelonian heart chambers and circulation path (see book figure 12.33).

Squamate Heart Figure 13.18. Squamate heart chambers and circulation path (book figure 12.35).

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

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

Two Aortic Trunks Figure 13.20. Turtle heart and two aortic trunks emerging . Figure 13.21. Crocodilian foramen of Panizza connects two aortic trunks at base (see book figure 12.36).

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

Adult Mammalian Heart Figure 13.22. Adult heart blood flow (see book figure 12.42).

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 13.23. Adult heart blood flow (book figure 12.13).

Aortic Arches (cont’d.) Figure 13.24. Basic pattern of aortic arches and dorsal aortae. Figure 13.25. Ventral perspective of aortic arches (book figure 12.19).

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

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 13.27. Aortic arches, internal carotids (ic) and pulmonary artery (book figure 12.14).

Tetrapod Aortic Arches 1st and 2nd arches lost Dorsal segment dropped between 3rd and 4th arches Ductus caroticus Figure 13.28. Adult aortic arches (see book figure 12.17).

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 13.29. Aortic arches, internal carotid (ic), external carotic (ec) and common carotid (cc) (book figure 12.14).

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 13.30. Adult aortic arches (book figure 14.19).

Figure 13.31. Modifications of aortic arches and dorsal aortae into mature mammalian vascular system.

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 13.32. Modifications of aortic arches and their derivative in anamniotes (book figure 12.14).

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 13.33. Adult aortic arches (book figure 12.19). Figure 13.34. Left aortic arches (book figure 12.17).

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

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 13.35. Modifications of basic venous patterns showing sinus venosus (S) (book figure 12.21).

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

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

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

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

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 13.36. Ventral view of anterior venous channels of cat and human (a) and ventral view of azygos of rhesus monkey (b).

Azygos and Hemiazygos Figure 13.37. Ventral view of venous channels of rabbit (see book figure 12.23).

Fetal Circulation Figure 13.38. Circulation of mammalian fetus (see book figure 12.42).

Fetal Circulation (cont’d.) Figure 13.39. Fetal circulation before birth.

Fetal Circulation (cont’d.) Figure 13.40. 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).

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 13.41. Foramen ovale in fetal circulation system.

Fetal Circulation (cont’d.) In right ventricle, oxy. blood sent to pulmonary artery Lungs nonfunctional Ductus arteriosus diverts blood from lungs Figure 13.42. Adult aortic arches of mammal. Figure 13.43. Left aortic arches with ductus arteriosus.

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)

Figure 13.44. Post birth modifications in fetal circulation.