Species difference

SPECIES DIFFERENCE

Horse

  • The base is broader and the length from the base to apex is shorter.
  • The long axis is more oblique.
  • The anterior border is more strongly convex.
  • It weighs about 2.9 kg to 3.1 kg.
  • The intermediate groove is absent.
  • Instead of os cordis, the aortic ring contains on the right side a plate of cartilage.
  • Sometimes a small plate of cartialge is present on the left side.

Dog

  • It is ovoid in shape. The apex is blunt and rounded.
  • The long axis is very oblique. The base faces the thoracic inlet.
  • The apex is in close relation to the diaphragm at its sternal part.
  • The left (ventral) and right (dorsal) longitudinal grooves meet with each other.
  • An intermediate groove is present.
  •  The weight of the heart of a medium sized dog is 150 to 180 gms. The tricuspid valve has two chief cusps and three or four small ones.
  • There are four musculi papillaris in the right ventricle, all of which spring from the septal wall.
  • The bicuspid valve consists of two large cusps and four or five small ones.
  • There are two musculi papillaris in the left ventricle, both of which arise from the lateral wall.

Fowl

  • It is proportionately larger.
  • It has the form of an acute cone and lies partly between the two lobes of the liver and partly anterior to them.
  •  The apex is directed backwards and slightly to the left of the median line.
  • There are two anterior vena cavae and a single posterior vena cava.
  • A muscular fold called the eustachian valve is found to the right of the opening of the posterior vena cava.
  • The right atrio ventricular opening is a curved slit and its valve is a muscular leaf, which has neither cusps nor chordae tendinae.
  • Musculi papillaris are absent in the right ventricle. The pulmonary artery opening has three semilunar cusps.
  • The left atrium is smaller than the right and the two pulmonary veins open into it by a common opening. The left atrio-ventricular valve is guarded by membranous cusps corresponding to the bicuspid valve of mammals.
  • The musculi papillaris and chorda tendinae are present in the left ventricle.
  • The aortic opening has the three semilunar cusps.
Last modified: Sunday, 16 October 2011, 11:29 AM