1. Cardiovascular System
Chapter 11

2. Warm-up
Differentiate between Systemic Circulation, Pulmonary Circulation and Coronary Circulation.

3. Systemic & Pulmonary Circulation

4. Coronary Circulation

5. Conduction System Intrinsic conduction system (nodal system)
Heart muscle cells contract, without nerve impulses!

6. Conduction System
Sinoatrial node = SA node (“pacemaker”)
right atrium

7. Conduction System Atrioventricular node = AV node
Junction of the right atrium and right ventricle

8. Conduction System Atrioventricular bundle = AV bundle (bundle of His)
In the interventricular septum
Bundle branches
Purkinje fibers
(ventricle wall muscles)

9. 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
“wringing” contraction – begins at apex, moves toward atria
Blood ejected

10. Cardiac Cycle Atria contract simultaneously
Atria relax, then ventricles contract
Systole = contraction
Diastole = relaxation
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

11. “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.

13. CO = SV x HR 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

14. Blood Vessels: The Vascular System
Carry blood away from the heart
Arteries
Arterioles

15. Blood Vessels: The Vascular System
Capillary beds - Exchanges between tissues and blood

16. Blood Vessels: The Vascular System
Return blood toward the heart
Venules
Veins

17. Blood Vessels: The Vascular System

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

19. Blood Vessels: Microscopic Anatomy
Tunic intima
Endothelium
Tunic media
Smooth muscle
Tunic externa
Mostly fibrous connective tissue

21. Differences Between Blood Vessels
Walls of arteries are the thickest
Lumens of veins are larger
Larger veins have valves to prevent backflow
Walls of capillaries are only one cell layer thick

23. Movement of Blood Most arterial blood is pumped by the heart
Veins use the “milking” action of muscles to help move blood

24. Capillary Beds Two types of vessels
Vascular shunt—vessel directly connecting an arteriole to a venule
True capillaries—exchange vessels

25. Capillary Beds

26. Capillary Beds