1. Cardiovascular System Chapter 11

2. Conduction System Intrinsic conduction system (nodal system)

3. Conduction System Sinoatrial node = SA node (“pacemaker”)

4. Conduction System Atrioventricular node = AV node

5. Conduction System Atrioventricular bundle = AV bundle (bundle of His) In the interventricular septum

6. Heart Contractions Contraction is initiated by the SA node Impulse spreads to AV node, atria contract Contraction is delayed Passes through AV bundle, bundle branches and Purkinje fibers

7. Cardiac Cycle Atria contract simultaneously Atria relax, then ventricles contract Systole = Diastole = Atrial contraction Mid-to-late diastole (ventricular filling) Ventricular systole (atria in diastole) Early diastole Isovolumetric contraction phase Ventricular ejection phase Isovolumetric relaxation Ventricular filling Left atrium Right atrium Left ventricle Right ventricle

8. “Lub – dub” beat of heart The “ lub” is the first heart sound, commonly termed S1, and is caused by turbulence from the closure of bicuspid (mitral) and tricuspid valves at the start of systole. The second sound,” dub” or S2, is caused by the closure of aortic and pulmonic valves, marking the end of systole.

9. Cardiac output (CO) Amount of blood pumped by each side (ventricle) of the heart in one minute Stroke volume (SV) Volume of blood pumped by each ventricle in one contraction (each heartbeat) Heart rate (HR) Typically 75 beats per minute CO = SV x HR

10. Electrocardiogram (ECG or EKG)

11. Blood Vessels: The Vascular System Arteries Arterioles

12. Blood Vessels: The Vascular System Capillary beds -

13. Blood Vessels: The Vascular System Venules Veins

14. Blood Vessels: The Vascular System

15. Blood Vessels: Microscopic Anatomy Three layers (tunics)

16. Blood Vessels: Microscopic Anatomy Tunic intima Tunic media Tunic externa

18. Differences Between Blood Vessels Walls of arteries are the thickest Lumens of veins are larger

20. Movement of Blood Most arterial blood is pumped by the heart

21. Capillary Beds Two types of vessels Vascular shunt— True capillaries—

22. Capillary Beds