Comparative anatomy of heart structure
1. All chordates have a circulatory or vascular
system comprising a system of vessels and channels through which 2 kinds of
fluids travel in separate, yet interconnected vessels. The fluids are the blood
and the lymph
2. The
blood vascular system is a closed system in vertebrates. It has a contractile heart and continuous
tube called vessels.
3. Heart is a hollow muscular pumping organ, It
is conical in shape. Heart is always
ventral to the gut, lying in a specialized coelomic compartment, the
pericardium.
4. Vertebrates have a pulsating heart It
receives blood from various parts of the body at the posterior end by means of
veins and pumps it into arteries at the anterior end, which carry the blood to
various organs including the breathing organs.
The heart of (Fish ) Shark
2. On
the dorsal side of the auricle there is a sac-like sinous which receives blood
from all parts of the body.
3. This
opens into the auricle by an aperture.
4. Auricle
communicate with the ventricle.
5. Ventricle
is continued ventrally and forward by another swollen part called conus
arteriosus.
6. Conus
extend forward as ventral aorta
7. Heart
of shark deals with only deoxygenated blood (Venous heart)
8. The
circulation is single circulation
The heart of frog
1. The
heart of frog has 2 auricles and one ventricle.
2. Auricles
are seperted by an interauricular septum.
3. Sinus
venosus on the dorsal side, opens into the right auricle through sinu-
auricular aperature.
4. Left
auricle contains - oxygenated blood.
5. The
2 auricles open into the ventricle by a common aperature which is guarded by
the auriculo-ventricular valve.
The heart of reptiles
1. The
heart of reptiles show improvement over the amphibians.
2. The
heart of reptile is of incomplete 4 chambers.
3. Sinus
venosus merged with the right auricle.
4. Right
and left auricles are completely seperated by interauricular septum.
5. The
ventricle is also divided imperfectly into two halves.
6. Conus
split upto the base into 2 vessels namely, pulmnory artery and aorta, that
cross each other.
Heart of Bird/ Mammal
1. The
first land vertebrates to have achieved complete separation of pulmnory and
systemic circulation.
2. Heart-
large and 4 –chambered,
3. Sinus
venosus and conus are absent.
4. Right
auricle - deoxygenated blood, 2 postcaval and 1 precaval vein
5. Left
auricle contains oxygenated blood and opening of pulmnory vein.
6. Right
auricle opens into Right ventricle by
monocuspid valve.
7. Left
auricle open into Left ventricle by bicuspid
valve.
8. Heart-
4 chambered, completely divided auricle and ventricle.
9. Right
auricle opens into Right ventricle by tricuspid
valve.
10.
Left auricle opens into Left
ventricle by bicuspid valve.
11.
Wall of heart supplied by coronary
arteries.
12.
Thus, the well defined circulatory
system helps in complete separation pulmnory and systemic circulation and the
complex nature of the heart anatomy,
13.
The circulation is double.
In bird Right systemic is present
No comments:
Post a Comment