Layers of the Pericardium and Heart Wall (Nursing)

00:01 So now let's Look at the location of the heart in our thoracic cavity or the mediastinum.

00:09 The heart is located slightly to the left and in the cardiac notch between the lungs.

00:19 The heart is deep to the sternum and superior to the diaphragm.

00:27 If we look from a superior view of the thoracic cavity, we find that the heart sits in the pericardium which is a serous membrane surrounding the heart and in between the lungs.

00:41 The pericardium is a double-walled sac that surrounds the heart.

00:46 It's made up of two layers.

00:51 First you have the superficial fibrous pericardium.

00:56 This layer is going to function to protect and anchor the heart to the surrounding structures.

01:02 It also prevents the heart from overfilling.

01:06 Deep to the fibrous pericardium, we have the second layer which is referred to as the serous pericardium.

01:14 This has two layers as well.

01:16 It has a parietal layer which lines the internal surface of the fibrous pericardium and then it has an internal visceral layer which is also referred to as the epicardium and is found on the external surface of the heart.

01:33 These two layers, the parietal and visceral layers of the serous pericardium are going to have a cavity in between them known as the pericardial cavity.

01:45 This cavity has a fluid in it that helps to decrease friction since the heart is moving so much and you know friction causes heat so we need a way to decrease that friction and that's done here between the parietal and visceral layers.

02:04 So recall from the previous slides that the visceral layer of the serous pericardium is called the epicardium.

02:13 The myocardium is going to be just deep to this epicardium and includes circular or spiral bundles of contractile cardiac muscles.

02:26 Also, the internal portion of the heart and the part that's going to form an anchor, the heart valves, is known as the cardiac skeleton.

02:38 This is a criss-crossing interlacing layer of connective tissue that's going to anchor our cardiac muscle fibers, support the great vessels that as the aorta and the pulmonary trunk as well as the semilunar valves and it's going to limit the spread of the action potentials to specific pass in the heart.

03:02 Deep to the myocardium, we have the innermost layer which is known as the endocardium.

03:09 The endocardium is going to be continuous with the endothelial lining of our blood vessels.

03:16 This layer is going to line the heart's chambers as well as cover the cardiac skeleton of valves.