CARDIAC ELECTRICAL ACTIVITY-NODES

SUMMARY

1. Conducts impulses from SA node ⟹ AV node ⟹ bundle of His ⟹ right & left branches ⟹ subendocardial Purkinje fibers.

2. SA node: situated in the right atrium, just below the SVC, atop the crista terminalis. Contains P (pacemaker) cells.

3. AV node: situated in the IA septum, above & to the left of opening of coronary sinus.

4. Because the fibrous framework of the heart separates the atria from ventricles, the bundle is the only means of conducting normal impulses from the atria to ventricles.



Image: J. Heuser, CC BY 2.5 [Accessed 7 Apr. 2019].

Reference(s)

Barrett, K.E., Barman, S.M., Boitano, S., Brooks, H.L., Weitz, M., Brian Patrick Kearns, Ganong, W.F. and Mcgraw-Hill Education (Firm (2016). Ganong’s review of medical physiology. 25th ed. New York: Mcgraw Hill Education.
Hall, J.E. and Hall, M.E. (2020). Guyton And Hall Textbook Of Medical Physiology. 14th ed. S.L.: Elsevier - Health Science.
West, J.B. and Luks, A.M. (2021). West’s Pulmonary Pathophysiology. Lippincott Williams & Wilkins.