Heart 8 around the two ventricles and proceeding toward the apex. This complex swirling pattern allows the heart to pump blood more effectively. There are two types of cells in cardiac muscle: muscle cells which have the ability to contract easily, and pacemaker cells of the conducting system. The muscle cells make up the bulk (99%) of cells in the atria and ventricles. These contractile cells are connected by intercalated discs which allow a rapid response to impulses of action potential from the pacemaker cells. The intercalated discs allow the cells to act as a syncytium and enable the contractions that
Lateral ventricles flat, the lateral ventricles have a vaguely triangular cross-section. Ependyma, which are epithelial cells, cover the inside of the lateral ventricles. The anterior horn of lateral ventricle or "frontal horn", is the portion which connects to the 3rd ventricle, via the interventricular foramen. This portion of the lateral ventricle impinges on the frontal lobe, passing anteriorly and laterally, with slight inclination inferiorly. It is separated from the anterior horn of the other lateral ventricle by a thin neural sheet - septum pellucidum, which thus forms its medial boundary. The boundary facing exterior to the ventricle curvature is formed by the