Comparative anatomy of heart structure

 

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

1.     The heart of shark has only two chambers, namely an auricle and a ventricle.

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 separated 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.