# Morphologic and Morphometric Study of the Heart and Its Great Arteries in the Common Pheasant (Phasianus colchicus)

## TL;DR

This study describes the heart structure and muscle patterns in common pheasants, offering insights into avian cardiovascular adaptations and conservation.

## Contribution

The study provides new morphological and immunohistochemical data on the heart of the common pheasant, highlighting unique cardiovascular adaptations.

## Key findings

- The pheasant heart has a conical shape with significantly thicker left ventricular walls compared to the right.
- The left atrioventricular valve has branched chordae tendineae with complex cord structures.
- Purkinje fibers show strong desmin expression but no α-SMA, indicating specific functional adaptations.

## Abstract

This study investigates the morphological and morphometric characteristics of the heart and great arteries in the common pheasant (Phasianus colchicus). Five adult male bird were used. Different morphometric and histomorphometric parameters in the heart and its great arteries were measured. Detailed structure of the heart chambers was investigated using scanning electron microscope (SEM). The expression pattern of desmin α‐smooth muscle actin (α‐SMA) was evaluated by immunohistochemical staining. The heart was elongated and conical heart with mean length and width as 2.94 ± 0.46 and 2.38 ± 0.15 cm, respectively. The parietal wall of the right ventricle was composed of two distinct muscular layers. The left ventricular wall at middle and apical regions was thicker than right ventricular wall four and three times, respectively. At the level of SEM, the right muscular atrioventricular valve was attached to the right ventricular free wall by several muscular cords. The chordae tendineae of the left atrioventricular valve showed a branched appearance and each chordae tendineae was composed of three to four narrower cords twisted to each other's and attached to a common papillary muscle. The Purkinje fibre network was widely distributed in the myocardium and exhibited strong immunoreactivity for desmin but was negative for α‐ α‐SMA. In conclusion, the consistent morphological and immunohistochemical patterns observed across individuals provide a reliable description of cardiovascular adaptations in the common pheasant. The results contribute to the broader understanding of avian heart morphology and function, offering a foundation for comparative studies across bird species and informing conservation efforts for gamebirds.

The common pheasant heart is elongated and conical, with thicker left ventricular walls and a complex atrioventricular valve structure.

Purkinje fibres show strong desmin but no α‐SMA expression, providing detailed insights into cardiovascular morphology and adaptations in birds, supporting comparative and conservation studies.