MEDICAL PHYSIOLOGY

Detailed explanation-1: -The bundle of His is an elongated segment connecting the AV Node and the left and right bundle branches of the septal crest. It is approximately 1.8 cm long in an adult heart[4] and is primarily located deep within the dense connective tissue.

Detailed explanation-2: -The AV bundle arises from the compact node and penetrates the central fibrous body of the heart, branching into the right and left bundle branches. The left bundle branch has a subendocardial location over the left ventricular septal surface, and it further subdivides into anterior and posterior fascicles.

Detailed explanation-3: -The right bundle branch courses down the right side of interventricular septum near the endocardium in its upper third, deeper in the muscular portion of the septum in the middle third, and then again near the endocardium in its lower third.

Detailed explanation-4: -After leaving the central fibrous body, it then bifurcates into the right and left bundle branches. The right bundle branch passes within the myocardium of the interventricular septum and the left bundle branch primarily travels subendocardially along the septum in the left ventricle (as noted above).