BIO 11 Lecture Notes - Lecture 24: Interatrial Septum, Interventricular Septum, Chordae Tendineae
Document Summary
Cone-shaped, slightly to the left in thoracic cavity. Posterior to the sternum in the mediastinum and rests on the diaphragm. Apex - point of the cone - points toward left hip. Its flattened base is its posterior side (not inferior) Externally, an indentation (atrioventricular sulcus) - found at boundary between atria and ventricles. Another depression - interventricular sulcus (groove) is located between the ventricles. Internal surface of the right atrium has muscular ridges on its anterior side - pectinate muscles. Atria are separated by a thin wall - interatrial septum. Small indentation in the interatrial septum - fossa ovalis. Ventricles have a ridged surface created by irregular protrusions of cardiac muscle tissue. Each ventricle contains finger-like projections of muscle - papillary muscles - attached by chordae tendineae. Ventricles separated by a thick, muscular wall - the interventricular septum. This backward flow is prevented by right and left atrioventricular valves.
