Comparative Anatomy Circulatory System

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Comparative AnatomyCirculatory System

• Kardong
• Chapter 12

Part 13
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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.
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Arteries, Veins, and Capillaries
Figure 13.2. Blood vessel microanatomy..
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Aortic arches- Within pharyngeal arches
Figure 13.3. Basic circulatory pattern of
amniote embryo.
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Aortic arches- Within pharyngeal arches
(discussed later)
Figure 13.4-5. Embryological development of
aortic arches (see book figures 12.9 -10).
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Portal Systems

• Veins that drain an organ and dump blood into
  another organ instead of heart

Figure 13.6. Portal systems of craniates.
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Portal Systems (cont.)

• 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).
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Portal Systems (cont.)
Figure 13.8. Hypophyseal portal system (book
figure 15.15) .
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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).
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Fish Heart (cont.)

• Fish heart
• Sinus venosus
• Atrium
• Ventricle
• Conus arteriosus

Figure 13.10. Fish with four chambered heart
(book figure 12.27).
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Fish Heart (cont.)

• Sinus venosus
• Thin-walled venous chamber
• Receives blood from ducts of Cuvier, coronary
  veins, hepatic veins
• Atrium
• Large and thin walled
• Dorsal to ventricle

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Fish Heart (cont.)

• Ventricle
• Dumps into conus arteriosus- continuous with
  aorta
• Chambers separated by valves sino-atrial valve,
  atrio-ventricular valve, 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

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

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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).
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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.
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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

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

• Cavum venosum (CV) - internal pocket e.g., turtle
• Blood collected from post cava through sinus
  venosus from 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

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Turtle Heart
Figure 13.17. Chelonian heart chambers and
circulation path (see book figure 12.33).
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Squamate Heart
Figure 13.18. Squamate heart chambers and
circulation path (book figure 12.35).
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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

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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.
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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).
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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

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Adult Mammalian Heart
Figure 13.22. Adult heart blood flow (see book
figure 12.42).
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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).
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Aortic Arches (cont.)
Figure 13.24. Basic pattern of aortic arches and
dorsal aortae.
Figure 13.25. Ventral perspective of aortic
arches (book figure 12.19).
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Figure 13.26. Left aortic arches (see book
figure 12.17).
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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 13.27. Aortic arches, internal carotids
(ic) and pulmonary artery (book figure 12.14).
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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).
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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 13.29. Aortic arches, internal carotid
(ic), external carotic (ec) and common carotid
(cc) (book figure 12.14).
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Tetrapod Aortic Arches (cont.)

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

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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).
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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

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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

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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

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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

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Modifications to Basic Venous System

• Azygous- vestige of right post cardinal vein
• 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).
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Azygos and Hemiazygos
Figure 13.37. Ventral view of venous channels of
rabbit (see book figure 12.23).
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Fetal Circulation
Figure 13.38. Circulation of mammalian fetus
(see book figure 12.42).
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Fetal Circulation (cont.)
Figure 13.39. Fetal circulation before birth.
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Fetal Circulation (cont.)
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).
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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 13.41. Foramen ovale in fetal circulation
system.
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Fetal Circulation (cont.)

• In right ventricle, oxy. blood sent to pulmonary
  artery
• Lungs nonfunctional
• Ductus arteriosus diverts blood from lungs

Figure 13.43. Left aortic arches with ductus
arteriosus.
Figure 13.42. Adult aortic arches of mammal.
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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)

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Figure 13.44. Post birth modifications in fetal
circulation.