In contrast to cardiac myocytes, endothelial cells have a great capacity for regeneration and for covering any breach in their continuity. If the original insult is removed, which without appropriate treatment is not often, the valve heals by fibrosis, but a shrunken, distorted, insufficient, or stenotic valve may remain. The anterior half of the right ventricle of a plastinated porcine heart. Swine have a single anterior papillary muscle, one to three posterior papillary muscles and one to three septal papillary muscles in the right ventricle .
The paper towels should not be placed through the AV valves as this will abnormally distort the valve leaflets. Adult as well as infant hearts can be sectioned in tomographic planes if prepared by the above described methods. Actual tomographic cutting of the heart can be done with the use of a large 12- to 16-in knife, which allows smooth, straight sectioning. Sectioning the heart in tomographic planes without formalin fixation will result in irregular rough cavity walls and distortions in the cardiac chambers. Per J. Willis Hurst, MD, this photograph was published in the first edition of Heart Disease by Dr Paul White.
The anterior papillary muscle is visible here as well as the moderator band, originating on the anterior papillary muscle and inserting at multiple points on the free wall. The gross pathologic features of feline HCM include an enlarged heart, with comparatively massive symmetrical concentric hypertrophy of both ventricles in the majority of cases, but especially notable for the left ventricle (Fig. 1-51A). Some cases have asymmetrical hypertrophy of the left ventricle, with the ventricular septum thicker than the left ventricular free wall. Findings of lesser frequency include atrial thrombi, focal areas of ventricular fibrosis, and fibrosis of the endocardium in the region of the left ventricular outflow tract. Hypertrophic cardiomyopathy, the most common form of cardiomyopathy in cats, is a diastolic disorder, resulting from ventricular myocardial hypertrophy in the absence of an obvious cause.
The usual tissue block taken for routine histology is of left ventricular papillary muscle, as this area is one of the most susceptible to damage and most representative in cases of generalized disease. The posterior half of the left ventricle of a plastinated ovine heart. Ovine hearts have a single anterior papillary muscle and may have one or two posterior papillary muscles in the left ventricle . This particular heart has one posterior papillary muscle, visible here, supporting the mitral valve through its chordae tendineae. A internal image of a ovine right ventricle, viewed superiorly. Ovine hearts have one anterior papillary muscle, one or two posterior papillary muscles and one or two septal papillary muscles .
Necrobacillary myocarditis occurs in cattle secondary to extensive necrobacillosis in other tissues; the necrosuppurative reaction is typical for the organism. Other bacterial causes of suppurative myocarditis include Clostridium piliforme and Citrobacter koseri. There is also extensive myocarditis how many electrons does neon have in some systemic mycoses, such as Aspergillus terreus in dogs, particularly the German Shepherd dog. In these, it is often possible to demonstrate bacterial emboli. Clostridium chauvoei may produce necrotizing myocarditis similar to the typical lesion in skeletal muscle (Fig. 1-47A).
Once a focus of infection is established, spread is most likely to occur by direct or indirect contact. In Africa, the transmission of the virus from wild Suidae to domestic pigs is primarily by the argasid tick Ornithodoros moubata, a true biological vector and a reservoir of the virus in nature. Disseminated intravascular coagulation is a common and important intermediary mechanism of disease, but is not a disease in itself. It may be defined as a pathologic activation of the coagulation system that leads to generalized intravascular clotting involving, in particular, arterioles and capillaries. The process may be acute, subacute, or chronic, and may be localized or generalized.
