The wall of the heart is composed of three distinct layers. 2. The outermost layer, the epicardium, is made up of connective tissue and epithelium, and houses blood and lymph capillaries along with coronary arteries. 3. The middle myocardium consists of cardiac muscle and is the thickest layer of the heart wall. 4. The inner endocardium is smooth and is made up of connective tissue and epithelium, and is continuous with the endothelium of major vessels joining the heart. a. The endocardium houses Purkinje fibers.
Lithuanian is the official language of Lithuania and is spoken by about 4 million native speakers. The language belongs to the Baltic branch of the Indo-European family. Researchers of Indo-European languages say Lithuanian is the most archaic of all the living Indo-European tongues.
Latvia. Since independence in 1991, the official language of Latvia has been the Baltic language of Latvian, a language closely related to Lithuanian. Latvian is spoken by the ethnic population, known as Letts, who make up 58.6% of the population. Russian is spoken by over 28.9% of the population, mainly Russian immigrants who live in the urban areas of the country. Minority languages include Belarusian, spoken by 3.9% of the population, Ukrainian, spoken by 2.6%, Polish, spoken by 2.5% and Lithuanian, spoken by a smaller population. BBC News Online country profile