Comparative Anatomy
Circulatory System
Kardong
Chapter 12
Part 13
Cardiovascular System

Arteries





Veins


Carry blood away from the
heart
Muscular, elastic fibrous
walls (see next figure)
Regulates blood pressure
Terminate in capillary bed
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
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
(a)
(b)
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
 Pulmonary artery from 6th arch
 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.