Exam 1 Review:  Chapter 18:  Pericardial Cavity and Pathology

pericardium - The membranous inelastic sac lined by a simple squamous serous membrane and filled with serous fluid which encloses the heart and the roots of the aorta and other large blood vessels and anchors the heart in the mediastinum; the sac itself consists of a fibrous layer (with attachments to the diaphragm, sternum, and costal cartilage) and the inner parietal serous layer while the visceral serous layer extends onto the external surface of the myocardium; it serves as a protective barrier from the spread of infection or inflammation from adjacent structures into the pericardial space and it serves to contain the heart and limit overfilling of the chambers; the lining serous membrane secretes the pericardial fluid which lubricates the surface of the heart as it contracts and twists within the pericardial space.

fibrous pericardium - The tough inelastic dense fibrous connective tissue which forms the outer layer of the pericardial sac which anchors the heart in the mediastinum; it provides protection and prevents overfilling of the heart.

serous pericardium - The simple squamous lining of the pericardial cavity, comprised of parietal and visceral layers, which secretes the serous fluid which lubricates the membrane surfaces and allows easy heart movement.

parietal layer of pericardium - The portion of the serous pericardium which lines the pericardial sac and is immediately internal to the fibrous pericardium.

visceral layer of pericardium = epicardium - The portion of the serous pericardium which lines the external surface of the heart and is immediately external to the myocardium, the adipose tissue on the myocardium, and the coronary vessels.

pericardial fluid - The pale yellow colored sterile serous fluid contained in the pericardial sac; typically about 20 mL are present.

pericardial cavity - The enclosed space between the parietal and visceral layers of the pericardium which contains the serous fluid which lubricates the membrane surfaces and allows easy heart movement.

Sketch and Label:

4. a cross section of the heart wall and pericardium.

Describe:

1. (or sketch) the position of the heart in the thoracic cavity and its membranous coverings.

 

The heart is located within the pericardial space which is within the mediastinum.  The apex of the heart is oriented to the left and lies beneath the costal cartilage of the sixth rib (left).  the base of the heart lies under the sternum at the level of rib 2.  The heart is housed within the pericardial sac.  The pericardial sac consists of an outer tough inelastic dense collagenous capsule, the fibrous pericardium, and an inner simple squamous serous membrane, the parietal pericardium.  The external surface of the heart is also covered with a simple squamous serous membrane, the visceral pericardium = epicardium, beneath which is a thin layer of dense fibrous connective tissue and variable amounts of adipose tissue which are superficial to the myocardium itself.  The pericardial lining is a serous membrane which secretes pericardial fluid which lubricates the surfaces as the heart twists during contraction with the pericardial sac.

2. the structure and function of the pericardium.

 

Structure:  The pericardium is the membranous inelastic sac lined by a simple squamous serous membrane and filled with serous fluid which encloses the heart and the roots of the aorta and other large blood vessels and anchors the heart in the mediastinum; the sac itself consists of a fibrous layer (with attachments to the diaphragm, sternum, and costal cartilage) and the inner parietal serous layer while the visceral serous layer extends onto the external surface of the myocardium. it serves as a protective barrier from the spread of infection or inflammation from adjacent structures and it serves to contain the heart and limit overfilling of the chambers.

Function:  The pericardium serves as a protective barrier from the spread of infection or inflammation from adjacent structures into the pericardial space and it serves to contain the heart and limit overfilling of the chambers. serves to contain the heart and limit overfilling of the chambers; the lining serous membrane secretes the pericardial fluid which lubricates the surface of the heart as it contracts and twists within the pericardial space.

pericarditis - Any acute or chronic inflammation of the pericardium; a wide variety of both infectious and noninfectious causes exist; approximately 120 mL of additional fluid can accumulate in the pericardium without an increase in pressure; further fluid accumulation can result in marked increases in pericardial pressure, eliciting decreased cardiac output and hypotension (cardiac tamponade); the rapidity of fluid accumulation influences the hemodynamic effect..

cardiac tamponade - A life-threatening condition caused by fluid under pressure in the pericardial cavity around the heart; fluid which collects in the pericardial sac can develop enough pressure to prevent the heart from relaxing completely between beats; usually, this fluid has accumulated rapidly, and the increase in pericardial pressure causes a sudden decrease in cardiac output; the mopst common cause is hemorrhage, but other causes include cancer, pericarditis from radiation therapy, infection or drug reactions, acute myocardial infarction, TB, Systemic Lupus Erythematosus, and dissecting aortic aneurysm.

See evidence of fatal hemorrhage in the pericardium below: