1. Findendocardium and adjacent myocardium on the cross-section in the internal segment of the ventricular wall:
Endocardium has a histological structure similar to that of the vessel wall; on the inner surface there are nuclei of the endothelial cells, underneath – the subendothelial layer (loose connective tissue), still deeper – myo-elastic layer with smooth muscle cells and elastic fibers;
Myocardium is formed by bands contractive coelomic muscle fibers (mainly axial sections, partially cross-sections and diagonal sections), enclosed by layers of loose connective tissue containing fine blood vessels;
Beneath the endocardium, the myocardium may contain large-sized pale-colored atypic (conducting) cardiac myocytes; their diameter is ab. 15 micrometer), the sarcoplasm is pale, the nuclei are large, they are free from cross striation.
2. Draw a segment of endocardium with adjacent myocardium. Point out:
I - endocardium
(1 - endothelium, 2 - subendothelial layer, 3 – smooth myocytes of the myo-elastic layer),
II - myocardium (4 – cardiac (contractive) myofibers, 5 - conducting cardiomyocytes, 6 - layers of connective tissue containing fine blood vessels). 4. Define and write significant features of the preparation