RESPIRATORY SYSTEM
The caudodorsal part of the nasal cavity is lined by sensitive olfactory epithelium and this gives the guinea pig a keen sense of smell. The larynx is typical of all mammals in that it has five cartilages but there is no laryngeal ventricle.
In spite of their wide vocal variety, guinea pigs have small and poorly developed vocal cords (Breazile & Brown 1976).The caudal tongue is continuous with the soft palate, except for the palatal ostium (previously called the inter- pharyngeal ostium) in the middle (Fig. 9.8). This aperture forms the only connection between the oropharynx and the pharynx. The folds of soft palate around this hole are called the velopharyngeal recess (Timm et al. 1987).
The heart occupies a disproportionately large part of the thorax and leaves only a narrow space for the lungs on each side. The right lung has four lobes (cranial, middle, accessory, and caudal) that are separated by a deep fissure. The left lung has three lobes: cranial, middle, and caudal (Breazile & Brown 1976).