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The ureter is surrounded by two muscular layers, an inner longitudinal layer of muscle, and an outer circular or spiral layer of muscle. [6] [7] The lower third of the ureter has a third muscular layer. [7] Beyond these layers sits an adventitia containing blood vessels, lymphatic vessels, and veins. [7]
The heart is a muscular organ situated in the mediastinum.It consists of four chambers, four valves, two main arteries (the coronary arteries), and the conduction system. The left and right sides of the heart have different functions: the right side receives de-oxygenated blood through the superior and inferior venae cavae and pumps blood to the lungs through the pulmonary artery, and the left ...
The swirling pattern of myocardium helps the heart pump effectively. The middle layer of the heart wall is the myocardium, which is the cardiac muscle—a layer of involuntary striated muscle tissue surrounded by a framework of collagen. The cardiac muscle pattern is elegant and complex, as the muscle cells swirl and spiral around the chambers ...
The heart wall is a three-layered structure with a thick layer of myocardium sandwiched between the inner endocardium and the outer epicardium (also known as the visceral pericardium). The inner endocardium lines the cardiac chambers, covers the cardiac valves , and joins with the endothelium that lines the blood vessels that connect to the heart.
Serous membranes have two layers. The parietal layers of the membranes line the walls of the body cavity (pariet- refers to a cavity wall). The visceral layer of the membrane covers the organs (the viscera). Between the parietal and visceral layers is a very thin, fluid-filled serous space, or cavity. [4]
The heart works by pumping blood around the body allowing oxygen, nutrients, waste, hormones and white blood cells to be transported. Diagram of the human heart. The heart is composed of two atria and two ventricles. The primary purpose of the atria is to allow uninterrupted venous blood flow to the heart during ventricular systole.
The heart's cardiac skeleton comprises four dense connective tissue rings that encircle the mitral and tricuspid atrioventricular (AV) canals and extend to the origins of the pulmonary trunk and aorta. This provides crucial support and structure to the heart while also serving to electrically isolate the atria from the ventricles. [1]
Illustration depicting the layers of the heart wall including the innermost endocardium. The endocardium (pl.: endocardia) is the innermost layer of tissue that lines the chambers of the heart. Its cells are embryologically and biologically similar to the endothelial cells that line blood vessels. The endocardium also provides protection to the ...